text: (function (global, factory) {
    typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
    typeof define === 'function' && define.amd ? define(['exports'], factory) :
    (factory((global.d3 = global.d3 || {})));
  }(this, function (exports) { 'use strict';
  
    function ascending(a, b) {
      return a < b ? -1 : a > b ? 1 : a >= b ? 0 : NaN;
    }
  
    function bisector(compare) {
      if (compare.length === 1) compare = ascendingComparator(compare);
      return {
        left: function(a, x, lo, hi) {
          if (lo == null) lo = 0;
          if (hi == null) hi = a.length;
          while (lo < hi) {
            var mid = lo + hi >>> 1;
            if (compare(a[mid], x) < 0) lo = mid + 1;
            else hi = mid;
          }
          return lo;
        },
        right: function(a, x, lo, hi) {
          if (lo == null) lo = 0;
          if (hi == null) hi = a.length;
          while (lo < hi) {
            var mid = lo + hi >>> 1;
            if (compare(a[mid], x) > 0) hi = mid;
            else lo = mid + 1;
          }
          return lo;
        }
      };
    }
  
    function ascendingComparator(f) {
      return function(d, x) {
        return ascending(f(d), x);
      };
    }
  
    var ascendingBisect = bisector(ascending);
    var bisectRight = ascendingBisect.right;
    var bisectLeft = ascendingBisect.left;
  
    function descending(a, b) {
      return b < a ? -1 : b > a ? 1 : b >= a ? 0 : NaN;
    }
  
    function number(x) {
      return x === null ? NaN : +x;
    }
  
    function variance(array, f) {
      var n = array.length,
          m = 0,
          a,
          d,
          s = 0,
          i = -1,
          j = 0;
  
      if (f == null) {
        while (++i < n) {
          if (!isNaN(a = number(array[i]))) {
            d = a - m;
            m += d / ++j;
            s += d * (a - m);
          }
        }
      }
  
      else {
        while (++i < n) {
          if (!isNaN(a = number(f(array[i], i, array)))) {
            d = a - m;
            m += d / ++j;
            s += d * (a - m);
          }
        }
      }
  
      if (j > 1) return s / (j - 1);
    }
  
    function deviation(array, f) {
      var v = variance(array, f);
      return v ? Math.sqrt(v) : v;
    }
  
    function extent(array, f) {
      var i = -1,
          n = array.length,
          a,
          b,
          c;
  
      if (f == null) {
        while (++i < n) if ((b = array[i]) != null && b >= b) { a = c = b; break; }
        while (++i < n) if ((b = array[i]) != null) {
          if (a > b) a = b;
          if (c < b) c = b;
        }
      }
  
      else {
        while (++i < n) if ((b = f(array[i], i, array)) != null && b >= b) { a = c = b; break; }
        while (++i < n) if ((b = f(array[i], i, array)) != null) {
          if (a > b) a = b;
          if (c < b) c = b;
        }
      }
  
      return [a, c];
    }
  
    var array = Array.prototype;
  
    var slice = array.slice;
    var map = array.map;
  
    function constant(x) {
      return function() {
        return x;
      };
    }
  
    function identity(x) {
      return x;
    }
  
    function range(start, stop, step) {
      start = +start, stop = +stop, step = (n = arguments.length) < 2 ? (stop = start, start = 0, 1) : n < 3 ? 1 : +step;
  
      var i = -1,
          n = Math.max(0, Math.ceil((stop - start) / step)) | 0,
          range = new Array(n);
  
      while (++i < n) {
        range[i] = start + i * step;
      }
  
      return range;
    }
  
    var e10 = Math.sqrt(50);
    var e5 = Math.sqrt(10);
    var e2 = Math.sqrt(2);
    function ticks(start, stop, count) {
      var step = tickStep(start, stop, count);
      return range(
        Math.ceil(start / step) * step,
        Math.floor(stop / step) * step + step / 2, // inclusive
        step
      );
    }
  
    function tickStep(start, stop, count) {
      var step0 = Math.abs(stop - start) / Math.max(0, count),
          step1 = Math.pow(10, Math.floor(Math.log(step0) / Math.LN10)),
          error = step0 / step1;
      if (error >= e10) step1 *= 10;
      else if (error >= e5) step1 *= 5;
      else if (error >= e2) step1 *= 2;
      return stop < start ? -step1 : step1;
    }
  
    function sturges(values) {
      return Math.ceil(Math.log(values.length) / Math.LN2) + 1;
    }
  
    function histogram() {
      var value = identity,
          domain = extent,
          threshold = sturges;
  
      function histogram(data) {
        var i,
            n = data.length,
            x,
            values = new Array(n);
  
        for (i = 0; i < n; ++i) {
          values[i] = value(data[i], i, data);
        }
  
        var xz = domain(values),
            x0 = xz[0],
            x1 = xz[1],
            tz = threshold(values, x0, x1);
  
        // Convert number of thresholds into uniform thresholds.
        if (!Array.isArray(tz)) tz = ticks(x0, x1, tz);
  
        // Remove any thresholds outside the domain.
        var m = tz.length;
        while (tz[0] <= x0) tz.shift(), --m;
        while (tz[m - 1] >= x1) tz.pop(), --m;
  
        var bins = new Array(m + 1),
            bin;
  
        // Initialize bins.
        for (i = 0; i <= m; ++i) {
          bin = bins[i] = [];
          bin.x0 = i > 0 ? tz[i - 1] : x0;
          bin.x1 = i < m ? tz[i] : x1;
        }
  
        // Assign data to bins by value, ignoring any outside the domain.
        for (i = 0; i < n; ++i) {
          x = values[i];
          if (x0 <= x && x <= x1) {
            bins[bisectRight(tz, x, 0, m)].push(data[i]);
          }
        }
  
        return bins;
      }
  
      histogram.value = function(_) {
        return arguments.length ? (value = typeof _ === "function" ? _ : constant(_), histogram) : value;
      };
  
      histogram.domain = function(_) {
        return arguments.length ? (domain = typeof _ === "function" ? _ : constant([_[0], _[1]]), histogram) : domain;
      };
  
      histogram.thresholds = function(_) {
        return arguments.length ? (threshold = typeof _ === "function" ? _ : Array.isArray(_) ? constant(slice.call(_)) : constant(_), histogram) : threshold;
      };
  
      return histogram;
    }
  
    function threshold(array, p, f) {
      if (f == null) f = number;
      if (!(n = array.length)) return;
      if ((p = +p) <= 0 || n < 2) return +f(array[0], 0, array);
      if (p >= 1) return +f(array[n - 1], n - 1, array);
      var n,
          h = (n - 1) * p,
          i = Math.floor(h),
          a = +f(array[i], i, array),
          b = +f(array[i + 1], i + 1, array);
      return a + (b - a) * (h - i);
    }
  
    function freedmanDiaconis(values, min, max) {
      values = map.call(values, number).sort(ascending);
      return Math.ceil((max - min) / (2 * (threshold(values, 0.75) - threshold(values, 0.25)) * Math.pow(values.length, -1 / 3)));
    }
  
    function scott(values, min, max) {
      return Math.ceil((max - min) / (3.5 * deviation(values) * Math.pow(values.length, -1 / 3)));
    }
  
    function max(array, f) {
      var i = -1,
          n = array.length,
          a,
          b;
  
      if (f == null) {
        while (++i < n) if ((b = array[i]) != null && b >= b) { a = b; break; }
        while (++i < n) if ((b = array[i]) != null && b > a) a = b;
      }
  
      else {
        while (++i < n) if ((b = f(array[i], i, array)) != null && b >= b) { a = b; break; }
        while (++i < n) if ((b = f(array[i], i, array)) != null && b > a) a = b;
      }
  
      return a;
    }
  
    function mean(array, f) {
      var s = 0,
          n = array.length,
          a,
          i = -1,
          j = n;
  
      if (f == null) {
        while (++i < n) if (!isNaN(a = number(array[i]))) s += a; else --j;
      }
  
      else {
        while (++i < n) if (!isNaN(a = number(f(array[i], i, array)))) s += a; else --j;
      }
  
      if (j) return s / j;
    }
  
    function median(array, f) {
      var numbers = [],
          n = array.length,
          a,
          i = -1;
  
      if (f == null) {
        while (++i < n) if (!isNaN(a = number(array[i]))) numbers.push(a);
      }
  
      else {
        while (++i < n) if (!isNaN(a = number(f(array[i], i, array)))) numbers.push(a);
      }
  
      return threshold(numbers.sort(ascending), 0.5);
    }
  
    function merge(arrays) {
      var n = arrays.length,
          m,
          i = -1,
          j = 0,
          merged,
          array;
  
      while (++i < n) j += arrays[i].length;
      merged = new Array(j);
  
      while (--n >= 0) {
        array = arrays[n];
        m = array.length;
        while (--m >= 0) {
          merged[--j] = array[m];
        }
      }
  
      return merged;
    }
  
    function min(array, f) {
      var i = -1,
          n = array.length,
          a,
          b;
  
      if (f == null) {
        while (++i < n) if ((b = array[i]) != null && b >= b) { a = b; break; }
        while (++i < n) if ((b = array[i]) != null && a > b) a = b;
      }
  
      else {
        while (++i < n) if ((b = f(array[i], i, array)) != null && b >= b) { a = b; break; }
        while (++i < n) if ((b = f(array[i], i, array)) != null && a > b) a = b;
      }
  
      return a;
    }
  
    function pairs(array) {
      var i = 0, n = array.length - 1, p = array[0], pairs = new Array(n < 0 ? 0 : n);
      while (i < n) pairs[i] = [p, p = array[++i]];
      return pairs;
    }
  
    function permute(array, indexes) {
      var i = indexes.length, permutes = new Array(i);
      while (i--) permutes[i] = array[indexes[i]];
      return permutes;
    }
  
    function scan(array, compare) {
      if (!(n = array.length)) return;
      var i = 0,
          n,
          j = 0,
          xi,
          xj = array[j];
  
      if (!compare) compare = ascending;
  
      while (++i < n) if (compare(xi = array[i], xj) < 0 || compare(xj, xj) !== 0) xj = xi, j = i;
  
      if (compare(xj, xj) === 0) return j;
    }
  
    function shuffle(array, i0, i1) {
      var m = (i1 == null ? array.length : i1) - (i0 = i0 == null ? 0 : +i0),
          t,
          i;
  
      while (m) {
        i = Math.random() * m-- | 0;
        t = array[m + i0];
        array[m + i0] = array[i + i0];
        array[i + i0] = t;
      }
  
      return array;
    }
  
    function sum(array, f) {
      var s = 0,
          n = array.length,
          a,
          i = -1;
  
      if (f == null) {
        while (++i < n) if (a = +array[i]) s += a; // Note: zero and null are equivalent.
      }
  
      else {
        while (++i < n) if (a = +f(array[i], i, array)) s += a;
      }
  
      return s;
    }
  
    function transpose(matrix) {
      if (!(n = matrix.length)) return [];
      for (var i = -1, m = min(matrix, length), transpose = new Array(m); ++i < m;) {
        for (var j = -1, n, row = transpose[i] = new Array(n); ++j < n;) {
          row[j] = matrix[j][i];
        }
      }
      return transpose;
    }
  
    function length(d) {
      return d.length;
    }
  
    function zip() {
      return transpose(arguments);
    }
  
    var prefix = "$";
  
    function Map() {}
  
    Map.prototype = map$1.prototype = {
      constructor: Map,
      has: function(key) {
        return (prefix + key) in this;
      },
      get: function(key) {
        return this[prefix + key];
      },
      set: function(key, value) {
        this[prefix + key] = value;
        return this;
      },
      remove: function(key) {
        var property = prefix + key;
        return property in this && delete this[property];
      },
      clear: function() {
        for (var property in this) if (property[0] === prefix) delete this[property];
      },
      keys: function() {
        var keys = [];
        for (var property in this) if (property[0] === prefix) keys.push(property.slice(1));
        return keys;
      },
      values: function() {
        var values = [];
        for (var property in this) if (property[0] === prefix) values.push(this[property]);
        return values;
      },
      entries: function() {
        var entries = [];
        for (var property in this) if (property[0] === prefix) entries.push({key: property.slice(1), value: this[property]});
        return entries;
      },
      size: function() {
        var size = 0;
        for (var property in this) if (property[0] === prefix) ++size;
        return size;
      },
      empty: function() {
        for (var property in this) if (property[0] === prefix) return false;
        return true;
      },
      each: function(f) {
        for (var property in this) if (property[0] === prefix) f(this[property], property.slice(1), this);
      }
    };
  
    function map$1(object, f) {
      var map = new Map;
  
      // Copy constructor.
      if (object instanceof Map) object.each(function(value, key) { map.set(key, value); });
  
      // Index array by numeric index or specified key function.
      else if (Array.isArray(object)) {
        var i = -1,
            n = object.length,
            o;
  
        if (f == null) while (++i < n) map.set(i, object[i]);
        else while (++i < n) map.set(f(o = object[i], i, object), o);
      }
  
      // Convert object to map.
      else if (object) for (var key in object) map.set(key, object[key]);
  
      return map;
    }
  
    function nest() {
      var keys = [],
          sortKeys = [],
          sortValues,
          rollup,
          nest;
  
      function apply(array, depth, createResult, setResult) {
        if (depth >= keys.length) return rollup != null
            ? rollup(array) : (sortValues != null
            ? array.sort(sortValues)
            : array);
  
        var i = -1,
            n = array.length,
            key = keys[depth++],
            keyValue,
            value,
            valuesByKey = map$1(),
            values,
            result = createResult();
  
        while (++i < n) {
          if (values = valuesByKey.get(keyValue = key(value = array[i]) + "")) {
            values.push(value);
          } else {
            valuesByKey.set(keyValue, [value]);
          }
        }
  
        valuesByKey.each(function(values, key) {
          setResult(result, key, apply(values, depth, createResult, setResult));
        });
  
        return result;
      }
  
      function entries(map, depth) {
        if (++depth > keys.length) return map;
        var array, sortKey = sortKeys[depth - 1];
        if (rollup != null && depth >= keys.length) array = map.entries();
        else array = [], map.each(function(v, k) { array.push({key: k, values: entries(v, depth)}); });
        return sortKey != null ? array.sort(function(a, b) { return sortKey(a.key, b.key); }) : array;
      }
  
      return nest = {
        object: function(array) { return apply(array, 0, createObject, setObject); },
        map: function(array) { return apply(array, 0, createMap, setMap); },
        entries: function(array) { return entries(apply(array, 0, createMap, setMap), 0); },
        key: function(d) { keys.push(d); return nest; },
        sortKeys: function(order) { sortKeys[keys.length - 1] = order; return nest; },
        sortValues: function(order) { sortValues = order; return nest; },
        rollup: function(f) { rollup = f; return nest; }
      };
    }
  
    function createObject() {
      return {};
    }
  
    function setObject(object, key, value) {
      object[key] = value;
    }
  
    function createMap() {
      return map$1();
    }
  
    function setMap(map, key, value) {
      map.set(key, value);
    }
  
    function Set() {}
  
    var proto = map$1.prototype;
  
    Set.prototype = set.prototype = {
      constructor: Set,
      has: proto.has,
      add: function(value) {
        value += "";
        this[prefix + value] = value;
        return this;
      },
      remove: proto.remove,
      clear: proto.clear,
      values: proto.keys,
      size: proto.size,
      empty: proto.empty,
      each: proto.each
    };
  
    function set(object, f) {
      var set = new Set;
  
      // Copy constructor.
      if (object instanceof Set) object.each(function(value) { set.add(value); });
  
      // Otherwise, assume it’s an array.
      else if (object) {
        var i = -1, n = object.length;
        if (f == null) while (++i < n) set.add(object[i]);
        else while (++i < n) set.add(f(object[i], i, object));
      }
  
      return set;
    }
  
    function d3keys(map) {
      var keys = [];
      for (var key in map) keys.push(key);
      return keys;
    }
  
    function values(map) {
      var values = [];
      for (var key in map) values.push(map[key]);
      return values;
    }
  
    function entries(map) {
      var entries = [];
      for (var key in map) entries.push({key: key, value: map[key]});
      return entries;
    }
  
    function uniform(min, max) {
      min = min == null ? 0 : +min;
      max = max == null ? 1 : +max;
      if (arguments.length === 1) max = min, min = 0;
      else max -= min;
      return function() {
        return Math.random() * max + min;
      };
    }
  
    function normal(mu, sigma) {
      var x, r;
      mu = mu == null ? 0 : +mu;
      sigma = sigma == null ? 1 : +sigma;
      return function() {
        var y;
  
        // If available, use the second previously-generated uniform random.
        if (x != null) y = x, x = null;
  
        // Otherwise, generate a new x and y.
        else do {
          x = Math.random() * 2 - 1;
          y = Math.random() * 2 - 1;
          r = x * x + y * y;
        } while (!r || r > 1);
  
        return mu + sigma * y * Math.sqrt(-2 * Math.log(r) / r);
      };
    }
  
    function logNormal() {
      var randomNormal = normal.apply(this, arguments);
      return function() {
        return Math.exp(randomNormal());
      };
    }
  
    function irwinHall(n) {
      return function() {
        for (var sum = 0, i = 0; i < n; ++i) sum += Math.random();
        return sum;
      };
    }
  
    function bates(n) {
      var randomIrwinHall = irwinHall(n);
      return function() {
        return randomIrwinHall() / n;
      };
    }
  
    function exponential(lambda) {
      return function() {
        return -Math.log(1 - Math.random()) / lambda;
      };
    }
  
    function linear(t) {
      return +t;
    }
  
    function quadIn(t) {
      return t * t;
    }
  
    function quadOut(t) {
      return t * (2 - t);
    }
  
    function quadInOut(t) {
      return ((t *= 2) <= 1 ? t * t : --t * (2 - t) + 1) / 2;
    }
  
    function cubicIn(t) {
      return t * t * t;
    }
  
    function cubicOut(t) {
      return --t * t * t + 1;
    }
  
    function easeCubicInOut(t) {
      return ((t *= 2) <= 1 ? t * t * t : (t -= 2) * t * t + 2) / 2;
    }
  
    var exponent = 3;
  
    var polyIn = (function custom(e) {
      e = +e;
  
      function polyIn(t) {
        return Math.pow(t, e);
      }
  
      polyIn.exponent = custom;
  
      return polyIn;
    })(exponent);
  
    var polyOut = (function custom(e) {
      e = +e;
  
      function polyOut(t) {
        return 1 - Math.pow(1 - t, e);
      }
  
      polyOut.exponent = custom;
  
      return polyOut;
    })(exponent);
  
    var polyInOut = (function custom(e) {
      e = +e;
  
      function polyInOut(t) {
        return ((t *= 2) <= 1 ? Math.pow(t, e) : 2 - Math.pow(2 - t, e)) / 2;
      }
  
      polyInOut.exponent = custom;
  
      return polyInOut;
    })(exponent);
  
    var pi = Math.PI;
    var halfPi = pi / 2;
    function sinIn(t) {
      return 1 - Math.cos(t * halfPi);
    }
  
    function sinOut(t) {
      return Math.sin(t * halfPi);
    }
  
    function sinInOut(t) {
      return (1 - Math.cos(pi * t)) / 2;
    }
  
    function expIn(t) {
      return Math.pow(2, 10 * t - 10);
    }
  
    function expOut(t) {
      return 1 - Math.pow(2, -10 * t);
    }
  
    function expInOut(t) {
      return ((t *= 2) <= 1 ? Math.pow(2, 10 * t - 10) : 2 - Math.pow(2, 10 - 10 * t)) / 2;
    }
  
    function circleIn(t) {
      return 1 - Math.sqrt(1 - t * t);
    }
  
    function circleOut(t) {
      return Math.sqrt(1 - --t * t);
    }
  
    function circleInOut(t) {
      return ((t *= 2) <= 1 ? 1 - Math.sqrt(1 - t * t) : Math.sqrt(1 - (t -= 2) * t) + 1) / 2;
    }
  
    var b1 = 4 / 11;
    var b2 = 6 / 11;
    var b3 = 8 / 11;
    var b4 = 3 / 4;
    var b5 = 9 / 11;
    var b6 = 10 / 11;
    var b7 = 15 / 16;
    var b8 = 21 / 22;
    var b9 = 63 / 64;
    var b0 = 1 / b1 / b1;
    function bounceIn(t) {
      return 1 - bounceOut(1 - t);
    }
  
    function bounceOut(t) {
      return (t = +t) < b1 ? b0 * t * t : t < b3 ? b0 * (t -= b2) * t + b4 : t < b6 ? b0 * (t -= b5) * t + b7 : b0 * (t -= b8) * t + b9;
    }
  
    function bounceInOut(t) {
      return ((t *= 2) <= 1 ? 1 - bounceOut(1 - t) : bounceOut(t - 1) + 1) / 2;
    }
  
    var overshoot = 1.70158;
  
    var backIn = (function custom(s) {
      s = +s;
  
      function backIn(t) {
        return t * t * ((s + 1) * t - s);
      }
  
      backIn.overshoot = custom;
  
      return backIn;
    })(overshoot);
  
    var backOut = (function custom(s) {
      s = +s;
  
      function backOut(t) {
        return --t * t * ((s + 1) * t + s) + 1;
      }
  
      backOut.overshoot = custom;
  
      return backOut;
    })(overshoot);
  
    var backInOut = (function custom(s) {
      s = +s;
  
      function backInOut(t) {
        return ((t *= 2) < 1 ? t * t * ((s + 1) * t - s) : (t -= 2) * t * ((s + 1) * t + s) + 2) / 2;
      }
  
      backInOut.overshoot = custom;
  
      return backInOut;
    })(overshoot);
  
    var tau = 2 * Math.PI;
    var amplitude = 1;
    var period = 0.3;
    var elasticIn = (function custom(a, p) {
      var s = Math.asin(1 / (a = Math.max(1, a))) * (p /= tau);
  
      function elasticIn(t) {
        return a * Math.pow(2, 10 * --t) * Math.sin((s - t) / p);
      }
  
      elasticIn.amplitude = function(a) { return custom(a, p * tau); };
      elasticIn.period = function(p) { return custom(a, p); };
  
      return elasticIn;
    })(amplitude, period);
  
    var elasticOut = (function custom(a, p) {
      var s = Math.asin(1 / (a = Math.max(1, a))) * (p /= tau);
  
      function elasticOut(t) {
        return 1 - a * Math.pow(2, -10 * (t = +t)) * Math.sin((t + s) / p);
      }
  
      elasticOut.amplitude = function(a) { return custom(a, p * tau); };
      elasticOut.period = function(p) { return custom(a, p); };
  
      return elasticOut;
    })(amplitude, period);
  
    var elasticInOut = (function custom(a, p) {
      var s = Math.asin(1 / (a = Math.max(1, a))) * (p /= tau);
  
      function elasticInOut(t) {
        return ((t = t * 2 - 1) < 0
            ? a * Math.pow(2, 10 * t) * Math.sin((s - t) / p)
            : 2 - a * Math.pow(2, -10 * t) * Math.sin((s + t) / p)) / 2;
      }
  
      elasticInOut.amplitude = function(a) { return custom(a, p * tau); };
      elasticInOut.period = function(p) { return custom(a, p); };
  
      return elasticInOut;
    })(amplitude, period);
  
    function area(polygon) {
      var i = -1,
          n = polygon.length,
          a,
          b = polygon[n - 1],
          area = 0;
  
      while (++i < n) {
        a = b;
        b = polygon[i];
        area += a[1] * b[0] - a[0] * b[1];
      }
  
      return area / 2;
    }
  
    function centroid(polygon) {
      var i = -1,
          n = polygon.length,
          x = 0,
          y = 0,
          a,
          b = polygon[n - 1],
          c,
          k = 0;
  
      while (++i < n) {
        a = b;
        b = polygon[i];
        k += c = a[0] * b[1] - b[0] * a[1];
        x += (a[0] + b[0]) * c;
        y += (a[1] + b[1]) * c;
      }
  
      return k *= 3, [x / k, y / k];
    }
  
    // Returns the 2D cross product of AB and AC vectors, i.e., the z-component of
    // the 3D cross product in a quadrant I Cartesian coordinate system (+x is
    // right, +y is up). Returns a positive value if ABC is counter-clockwise,
    // negative if clockwise, and zero if the points are collinear.
    function cross(a, b, c) {
      return (b[0] - a[0]) * (c[1] - a[1]) - (b[1] - a[1]) * (c[0] - a[0]);
    }
  
    function lexicographicOrder(a, b) {
      return a[0] - b[0] || a[1] - b[1];
    }
  
    // Computes the upper convex hull per the monotone chain algorithm.
    // Assumes points.length >= 3, is sorted by x, unique in y.
    // Returns an array of indices into points in left-to-right order.
    function computeUpperHullIndexes(points) {
      var n = points.length,
          indexes = [0, 1],
          size = 2;
  
      for (var i = 2; i < n; ++i) {
        while (size > 1 && cross(points[indexes[size - 2]], points[indexes[size - 1]], points[i]) <= 0) --size;
        indexes[size++] = i;
      }
  
      return indexes.slice(0, size); // remove popped points
    }
  
    function hull(points) {
      if ((n = points.length) < 3) return null;
  
      var i,
          n,
          sortedPoints = new Array(n),
          flippedPoints = new Array(n);
  
      for (i = 0; i < n; ++i) sortedPoints[i] = [+points[i][0], +points[i][1], i];
      sortedPoints.sort(lexicographicOrder);
      for (i = 0; i < n; ++i) flippedPoints[i] = [sortedPoints[i][0], -sortedPoints[i][1]];
  
      var upperIndexes = computeUpperHullIndexes(sortedPoints),
          lowerIndexes = computeUpperHullIndexes(flippedPoints);
  
      // Construct the hull polygon, removing possible duplicate endpoints.
      var skipLeft = lowerIndexes[0] === upperIndexes[0],
          skipRight = lowerIndexes[lowerIndexes.length - 1] === upperIndexes[upperIndexes.length - 1],
          hull = [];
  
      // Add upper hull in right-to-l order.
      // Then add lower hull in left-to-right order.
      for (i = upperIndexes.length - 1; i >= 0; --i) hull.push(points[sortedPoints[upperIndexes[i]][2]]);
      for (i = +skipLeft; i < lowerIndexes.length - skipRight; ++i) hull.push(points[sortedPoints[lowerIndexes[i]][2]]);
  
      return hull;
    }
  
    function contains(polygon, point) {
      var n = polygon.length,
          p = polygon[n - 1],
          x = point[0], y = point[1],
          x0 = p[0], y0 = p[1],
          x1, y1,
          inside = false;
  
      for (var i = 0; i < n; ++i) {
        p = polygon[i], x1 = p[0], y1 = p[1];
        if (((y1 > y) !== (y0 > y)) && (x < (x0 - x1) * (y - y1) / (y0 - y1) + x1)) inside = !inside;
        x0 = x1, y0 = y1;
      }
  
      return inside;
    }
  
    function length$1(polygon) {
      var i = -1,
          n = polygon.length,
          b = polygon[n - 1],
          xa,
          ya,
          xb = b[0],
          yb = b[1],
          perimeter = 0;
  
      while (++i < n) {
        xa = xb;
        ya = yb;
        b = polygon[i];
        xb = b[0];
        yb = b[1];
        xa -= xb;
        ya -= yb;
        perimeter += Math.sqrt(xa * xa + ya * ya);
      }
  
      return perimeter;
    }
  
  var   pi$1 = Math.PI;
  var   tau$1 = 2 * pi$1;
    var epsilon = 1e-6;
    var tauEpsilon = tau$1 - epsilon;
    function Path() {
      this._x0 = this._y0 = // start of current subpath
      this._x1 = this._y1 = null; // end of current subpath
      this._ = [];
    }
  
    function path() {
      return new Path;
    }
  
    Path.prototype = path.prototype = {
      constructor: Path,
      moveTo: function(x, y) {
        this._.push("M", this._x0 = this._x1 = +x, ",", this._y0 = this._y1 = +y);
      },
      closePath: function() {
        if (this._x1 !== null) {
          this._x1 = this._x0, this._y1 = this._y0;
          this._.push("Z");
        }
      },
      lineTo: function(x, y) {
        this._.push("L", this._x1 = +x, ",", this._y1 = +y);
      },
      quadraticCurveTo: function(x1, y1, x, y) {
        this._.push("Q", +x1, ",", +y1, ",", this._x1 = +x, ",", this._y1 = +y);
      },
      bezierCurveTo: function(x1, y1, x2, y2, x, y) {
        this._.push("C", +x1, ",", +y1, ",", +x2, ",", +y2, ",", this._x1 = +x, ",", this._y1 = +y);
      },
      arcTo: function(x1, y1, x2, y2, r) {
        x1 = +x1, y1 = +y1, x2 = +x2, y2 = +y2, r = +r;
        var x0 = this._x1,
            y0 = this._y1,
            x21 = x2 - x1,
            y21 = y2 - y1,
            x01 = x0 - x1,
            y01 = y0 - y1,
            l01_2 = x01 * x01 + y01 * y01;
  
        // Is the radius negative? Error.
        if (r < 0) throw new Error("negative radius: " + r);
  
        // Is this path empty? Move to (x1,y1).
        if (this._x1 === null) {
          this._.push(
            "M", this._x1 = x1, ",", this._y1 = y1
          );
        }
  
        // Or, is (x1,y1) coincident with (x0,y0)? Do nothing.
        else if (!(l01_2 > epsilon));
  
        // Or, are (x0,y0), (x1,y1) and (x2,y2) collinear?
        // Equivalently, is (x1,y1) coincident with (x2,y2)?
        // Or, is the radius zero? Line to (x1,y1).
        else if (!(Math.abs(y01 * x21 - y21 * x01) > epsilon) || !r) {
          this._.push(
            "L", this._x1 = x1, ",", this._y1 = y1
          );
        }
  
        // Otherwise, draw an arc!
        else {
          var x20 = x2 - x0,
              y20 = y2 - y0,
              l21_2 = x21 * x21 + y21 * y21,
              l20_2 = x20 * x20 + y20 * y20,
              l21 = Math.sqrt(l21_2),
              l01 = Math.sqrt(l01_2),
              l = r * Math.tan((pi$1 - Math.acos((l21_2 + l01_2 - l20_2) / (2 * l21 * l01))) / 2),
              t01 = l / l01,
              t21 = l / l21;
  
          // If the start tangent is not coincident with (x0,y0), line to.
          if (Math.abs(t01 - 1) > epsilon) {
            this._.push(
              "L", x1 + t01 * x01, ",", y1 + t01 * y01
            );
          }
  
          this._.push(
            "A", r, ",", r, ",0,0,", +(y01 * x20 > x01 * y20), ",", this._x1 = x1 + t21 * x21, ",", this._y1 = y1 + t21 * y21
          );
        }
      },
      arc: function(x, y, r, a0, a1, ccw) {
        x = +x, y = +y, r = +r;
        var dx = r * Math.cos(a0),
            dy = r * Math.sin(a0),
            x0 = x + dx,
            y0 = y + dy,
            cw = 1 ^ ccw,
            da = ccw ? a0 - a1 : a1 - a0;
  
        // Is the radius negative? Error.
        if (r < 0) throw new Error("negative radius: " + r);
  
        // Is this path empty? Move to (x0,y0).
        if (this._x1 === null) {
          this._.push(
            "M", x0, ",", y0
          );
        }
  
        // Or, is (x0,y0) not coincident with the previous point? Line to (x0,y0).
        else if (Math.abs(this._x1 - x0) > epsilon || Math.abs(this._y1 - y0) > epsilon) {
          this._.push(
            "L", x0, ",", y0
          );
        }
  
        // Is this arc empty? We’re done.
        if (!r) return;
  
        // Is this a complete circle? Draw two arcs to complete the circle.
        if (da > tauEpsilon) {
          this._.push(
            "A", r, ",", r, ",0,1,", cw, ",", x - dx, ",", y - dy,
            "A", r, ",", r, ",0,1,", cw, ",", this._x1 = x0, ",", this._y1 = y0
          );
        }
  
        // Otherwise, draw an arc!
        else {
          if (da < 0) da = da % tau$1 + tau$1;
          this._.push(
            "A", r, ",", r, ",0,", +(da >= pi$1), ",", cw, ",", this._x1 = x + r * Math.cos(a1), ",", this._y1 = y + r * Math.sin(a1)
          );
        }
      },
      rect: function(x, y, w, h) {
        this._.push("M", this._x0 = this._x1 = +x, ",", this._y0 = this._y1 = +y, "h", +w, "v", +h, "h", -w, "Z");
      },
      toString: function() {
        return this._.join("");
      }
    };
  
    function tree_add(d) {
      var x = +this._x.call(null, d),
          y = +this._y.call(null, d);
      return add(this.cover(x, y), x, y, d);
    }
  
    function add(tree, x, y, d) {
      if (isNaN(x) || isNaN(y)) return tree; // ignore invalid points
  
      var parent,
          node = tree._root,
          leaf = {data: d},
          x0 = tree._x0,
          y0 = tree._y0,
          x1 = tree._x1,
          y1 = tree._y1,
          xm,
          ym,
          xp,
          yp,
          right,
          bottom,
          i,
          j;
  
      // If the tree is empty, initialize the root as a leaf.
      if (!node) return tree._root = leaf, tree;
  
      // Find the existing leaf for the new point, or add it.
      while (node.length) {
        if (right = x >= (xm = (x0 + x1) / 2)) x0 = xm; else x1 = xm;
        if (bottom = y >= (ym = (y0 + y1) / 2)) y0 = ym; else y1 = ym;
        if (parent = node, !(node = node[i = bottom << 1 | right])) return parent[i] = leaf, tree;
      }
  
      // Is the new point is exactly coincident with the existing point?
      xp = +tree._x.call(null, node.data);
      yp = +tree._y.call(null, node.data);
      if (x === xp && y === yp) return leaf.next = node, parent ? parent[i] = leaf : tree._root = leaf, tree;
  
      // Otherwise, split the leaf node until the old and new point are separated.
      do {
        parent = parent ? parent[i] = new Array(4) : tree._root = new Array(4);
        if (right = x >= (xm = (x0 + x1) / 2)) x0 = xm; else x1 = xm;
        if (bottom = y >= (ym = (y0 + y1) / 2)) y0 = ym; else y1 = ym;
      } while ((i = bottom << 1 | right) === (j = (yp >= ym) << 1 | (xp >= xm)));
      return parent[j] = node, parent[i] = leaf, tree;
    }
  
    function addAll(data) {
      var d, i, n = data.length,
          x,
          y,
          xz = new Array(n),
          yz = new Array(n),
          x0 = Infinity,
          y0 = Infinity,
          x1 = -Infinity,
          y1 = -Infinity;
  
      // Compute the points and their extent.
      for (i = 0; i < n; ++i) {
        if (isNaN(x = +this._x.call(null, d = data[i])) || isNaN(y = +this._y.call(null, d))) continue;
        xz[i] = x;
        yz[i] = y;
        if (x < x0) x0 = x;
        if (x > x1) x1 = x;
        if (y < y0) y0 = y;
        if (y > y1) y1 = y;
      }
  
      // If there were no (valid) points, inherit the existing extent.
      if (x1 < x0) x0 = this._x0, x1 = this._x1;
      if (y1 < y0) y0 = this._y0, y1 = this._y1;
  
      // Expand the tree to cover the new points.
      this.cover(x0, y0).cover(x1, y1);
  
      // Add the new points.
      for (i = 0; i < n; ++i) {
        add(this, xz[i], yz[i], data[i]);
      }
  
      return this;
    }
  
    function tree_cover(x, y) {
      if (isNaN(x = +x) || isNaN(y = +y)) return this; // ignore invalid points
  
      var x0 = this._x0,
          y0 = this._y0,
          x1 = this._x1,
          y1 = this._y1;
  
      // If the quadtree has no extent, initialize them.
      // Integer extent are necessary so that if we later double the extent,
      // the existing quadrant boundaries don’t change due to floating point error!
      if (isNaN(x0)) {
        x1 = (x0 = Math.floor(x)) + 1;
        y1 = (y0 = Math.floor(y)) + 1;
      }
  
      // Otherwise, double repeatedly to cover.
      else if (x0 > x || x > x1 || y0 > y || y > y1) {
        var z = x1 - x0,
            node = this._root,
            parent,
            i;
  
        switch (i = (y < (y0 + y1) / 2) << 1 | (x < (x0 + x1) / 2)) {
          case 0: {
            do parent = new Array(4), parent[i] = node, node = parent;
            while (z *= 2, x1 = x0 + z, y1 = y0 + z, x > x1 || y > y1);
            break;
          }
          case 1: {
            do parent = new Array(4), parent[i] = node, node = parent;
            while (z *= 2, x0 = x1 - z, y1 = y0 + z, x0 > x || y > y1);
            break;
          }
          case 2: {
            do parent = new Array(4), parent[i] = node, node = parent;
            while (z *= 2, x1 = x0 + z, y0 = y1 - z, x > x1 || y0 > y);
            break;
          }
          case 3: {
            do parent = new Array(4), parent[i] = node, node = parent;
            while (z *= 2, x0 = x1 - z, y0 = y1 - z, x0 > x || y0 > y);
            break;
          }
        }
  
        if (this._root && this._root.length) this._root = node;
      }
  
      // If the quadtree covers the point already, just return.
      else return this;
  
      this._x0 = x0;
      this._y0 = y0;
      this._x1 = x1;
      this._y1 = y1;
      return this;
    }
  
    function tree_data() {
      var data = [];
      this.visit(function(node) {
        if (!node.length) do data.push(node.data); while (node = node.next)
      });
      return data;
    }
  
    function tree_extent(_) {
      return arguments.length
          ? this.cover(+_[0][0], +_[0][1]).cover(+_[1][0], +_[1][1])
          : isNaN(this._x0) ? undefined : [[this._x0, this._y0], [this._x1, this._y1]];
    }
  
    function Quad(node, x0, y0, x1, y1) {
      this.node = node;
      this.x0 = x0;
      this.y0 = y0;
      this.x1 = x1;
      this.y1 = y1;
    }
  
    function tree_find(x, y, radius) {
      var data,
          x0 = this._x0,
          y0 = this._y0,
          x1,
          y1,
          x2,
          y2,
          x3 = this._x1,
          y3 = this._y1,
          quads = [],
          node = this._root,
          q,
          i;
  
      if (node) quads.push(new Quad(node, x0, y0, x3, y3));
      if (radius == null) radius = Infinity;
      else {
        x0 = x - radius, y0 = y - radius;
        x3 = x + radius, y3 = y + radius;
        radius *= radius;
      }
  
      while (q = quads.pop()) {
  
        // Stop searching if this quadrant can’t contain a closer node.
        if (!(node = q.node)
            || (x1 = q.x0) > x3
            || (y1 = q.y0) > y3
            || (x2 = q.x1) < x0
            || (y2 = q.y1) < y0) continue;
  
        // Bisect the current quadrant.
        if (node.length) {
          var xm = (x1 + x2) / 2,
              ym = (y1 + y2) / 2;
  
          quads.push(
            new Quad(node[3], xm, ym, x2, y2),
            new Quad(node[2], x1, ym, xm, y2),
            new Quad(node[1], xm, y1, x2, ym),
            new Quad(node[0], x1, y1, xm, ym)
          );
  
          // Visit the closest quadrant first.
          if (i = (y >= ym) << 1 | (x >= xm)) {
            q = quads[quads.length - 1];
            quads[quads.length - 1] = quads[quads.length - 1 - i];
            quads[quads.length - 1 - i] = q;
          }
        }
  
        // Visit this point. (Visiting coincident points isn’t necessary!)
        else {
          var dx = x - +this._x.call(null, node.data),
              dy = y - +this._y.call(null, node.data),
              d2 = dx * dx + dy * dy;
          if (d2 < radius) {
            var d = Math.sqrt(radius = d2);
            x0 = x - d, y0 = y - d;
            x3 = x + d, y3 = y + d;
            data = node.data;
          }
        }
      }
  
      return data;
    }
  
    function tree_remove(d) {
      if (isNaN(x = +this._x.call(null, d)) || isNaN(y = +this._y.call(null, d))) return this; // ignore invalid points
  
      var parent,
          node = this._root,
          retainer,
          previous,
          next,
          x0 = this._x0,
          y0 = this._y0,
          x1 = this._x1,
          y1 = this._y1,
          x,
          y,
          xm,
          ym,
          right,
          bottom,
          i,
          j;
  
      // If the tree is empty, initialize the root as a leaf.
      if (!node) return this;
  
      // Find the leaf node for the point.
      // While descending, also retain the deepest parent with a non-removed sibling.
      if (node.length) while (true) {
        if (right = x >= (xm = (x0 + x1) / 2)) x0 = xm; else x1 = xm;
        if (bottom = y >= (ym = (y0 + y1) / 2)) y0 = ym; else y1 = ym;
        if (!(parent = node, node = node[i = bottom << 1 | right])) return this;
        if (!node.length) break;
        if (parent[(i + 1) & 3] || parent[(i + 2) & 3] || parent[(i + 3) & 3]) retainer = parent, j = i;
      }
  
      // Find the point to remove.
      while (node.data !== d) if (!(previous = node, node = node.next)) return this;
      if (next = node.next) delete node.next;
  
      // If there are multiple coincident points, remove just the point.
      if (previous) return (next ? previous.next = next : delete previous.next), this;
  
      // If this is the root point, remove it.
      if (!parent) return this._root = next, this;
  
      // Remove this leaf.
      next ? parent[i] = next : delete parent[i];
  
      // If the parent now contains exactly one leaf, collapse superfluous parents.
      if ((node = parent[0] || parent[1] || parent[2] || parent[3])
          && node === (parent[3] || parent[2] || parent[1] || parent[0])
          && !node.length) {
        if (retainer) retainer[j] = node;
        else this._root = node;
      }
  
      return this;
    }
  
    function removeAll(data) {
      for (var i = 0, n = data.length; i < n; ++i) this.remove(data[i]);
      return this;
    }
  
    function tree_root() {
      return this._root;
    }
  
    function tree_size() {
      var size = 0;
      this.visit(function(node) {
        if (!node.length) do ++size; while (node = node.next)
      });
      return size;
    }
  
    function tree_visit(callback) {
      var quads = [], q, node = this._root, child, x0, y0, x1, y1;
      if (node) quads.push(new Quad(node, this._x0, this._y0, this._x1, this._y1));
      while (q = quads.pop()) {
        if (!callback(node = q.node, x0 = q.x0, y0 = q.y0, x1 = q.x1, y1 = q.y1) && node.length) {
          var xm = (x0 + x1) / 2, ym = (y0 + y1) / 2;
          if (child = node[3]) quads.push(new Quad(child, xm, ym, x1, y1));
          if (child = node[2]) quads.push(new Quad(child, x0, ym, xm, y1));
          if (child = node[1]) quads.push(new Quad(child, xm, y0, x1, ym));
          if (child = node[0]) quads.push(new Quad(child, x0, y0, xm, ym));
        }
      }
      return this;
    }
  
    function tree_visitAfter(callback) {
      var quads = [], next = [], q;
      if (this._root) quads.push(new Quad(this._root, this._x0, this._y0, this._x1, this._y1));
      while (q = quads.pop()) {
        var node = q.node;
        if (node.length) {
          var child, x0 = q.x0, y0 = q.y0, x1 = q.x1, y1 = q.y1, xm = (x0 + x1) / 2, ym = (y0 + y1) / 2;
          if (child = node[0]) quads.push(new Quad(child, x0, y0, xm, ym));
          if (child = node[1]) quads.push(new Quad(child, xm, y0, x1, ym));
          if (child = node[2]) quads.push(new Quad(child, x0, ym, xm, y1));
          if (child = node[3]) quads.push(new Quad(child, xm, ym, x1, y1));
        }
        next.push(q);
      }
      while (q = next.pop()) {
        callback(q.node, q.x0, q.y0, q.x1, q.y1);
      }
      return this;
    }
  
    function defaultX(d) {
      return d[0];
    }
  
    function tree_x(_) {
      return arguments.length ? (this._x = _, this) : this._x;
    }
  
    function defaultY(d) {
      return d[1];
    }
  
    function tree_y(_) {
      return arguments.length ? (this._y = _, this) : this._y;
    }
  
    function quadtree(nodes, x, y) {
      var tree = new Quadtree(x == null ? defaultX : x, y == null ? defaultY : y, NaN, NaN, NaN, NaN);
      return nodes == null ? tree : tree.addAll(nodes);
    }
  
    function Quadtree(x, y, x0, y0, x1, y1) {
      this._x = x;
      this._y = y;
      this._x0 = x0;
      this._y0 = y0;
      this._x1 = x1;
      this._y1 = y1;
      this._root = undefined;
    }
  
    function leaf_copy(leaf) {
      var copy = {data: leaf.data}, next = copy;
      while (leaf = leaf.next) next = next.next = {data: leaf.data};
      return copy;
    }
  
    var treeProto = quadtree.prototype = Quadtree.prototype;
  
    treeProto.copy = function() {
      var copy = new Quadtree(this._x, this._y, this._x0, this._y0, this._x1, this._y1),
          node = this._root,
          nodes,
          child;
  
      if (!node) return copy;
  
      if (!node.length) return copy._root = leaf_copy(node), copy;
  
      nodes = [{source: node, target: copy._root = new Array(4)}];
      while (node = nodes.pop()) {
        for (var i = 0; i < 4; ++i) {
          if (child = node.source[i]) {
            if (child.length) nodes.push({source: child, target: node.target[i] = new Array(4)});
            else node.target[i] = leaf_copy(child);
          }
        }
      }
  
      return copy;
    };
  
    treeProto.add = tree_add;
    treeProto.addAll = addAll;
    treeProto.cover = tree_cover;
    treeProto.data = tree_data;
    treeProto.extent = tree_extent;
    treeProto.find = tree_find;
    treeProto.remove = tree_remove;
    treeProto.removeAll = removeAll;
    treeProto.root = tree_root;
    treeProto.size = tree_size;
    treeProto.visit = tree_visit;
    treeProto.visitAfter = tree_visitAfter;
    treeProto.x = tree_x;
    treeProto.y = tree_y;
  
    var slice$1 = [].slice;
  
    var noabort = {};
  
    function Queue(size) {
      if (!(size >= 1)) throw new Error;
      this._size = size;
      this._call =
      this._error = null;
      this._tasks = [];
      this._data = [];
      this._waiting =
      this._active =
      this._ended =
      this._start = 0; // inside a synchronous task callback?
    }
  
    Queue.prototype = queue.prototype = {
      constructor: Queue,
      defer: function(callback) {
        if (typeof callback !== "function" || this._call) throw new Error;
        if (this._error != null) return this;
        var t = slice$1.call(arguments, 1);
        t.push(callback);
        ++this._waiting, this._tasks.push(t);
        poke(this);
        return this;
      },
      abort: function() {
        if (this._error == null) abort(this, new Error("abort"));
        return this;
      },
      await: function(callback) {
        if (typeof callback !== "function" || this._call) throw new Error;
        this._call = function(error, results) { callback.apply(null, [error].concat(results)); };
        maybeNotify(this);
        return this;
      },
      awaitAll: function(callback) {
        if (typeof callback !== "function" || this._call) throw new Error;
        this._call = callback;
        maybeNotify(this);
        return this;
      }
    };
  
    function poke(q) {
      if (!q._start) {
        try { start(q); } // let the current task complete
        catch (e) {
          if (q._tasks[q._ended + q._active - 1]) abort(q, e); // task errored synchronously
          else if (!q._data) throw e; // await callback errored synchronously
        }
      }
    }
  
    function start(q) {
      while (q._start = q._waiting && q._active < q._size) {
        var i = q._ended + q._active,
            t = q._tasks[i],
            j = t.length - 1,
            c = t[j];
        t[j] = end(q, i);
        --q._waiting, ++q._active;
        t = c.apply(null, t);
        if (!q._tasks[i]) continue; // task finished synchronously
        q._tasks[i] = t || noabort;
      }
    }
  
    function end(q, i) {
      return function(e, r) {
        if (!q._tasks[i]) return; // ignore multiple callbacks
        --q._active, ++q._ended;
        q._tasks[i] = null;
        if (q._error != null) return; // ignore secondary errors
        if (e != null) {
          abort(q, e);
        } else {
          q._data[i] = r;
          if (q._waiting) poke(q);
          else maybeNotify(q);
        }
      };
    }
  
    function abort(q, e) {
      var i = q._tasks.length, t;
      q._error = e; // ignore active callbacks
      q._data = undefined; // allow gc
      q._waiting = NaN; // prevent starting
  
      while (--i >= 0) {
        if (t = q._tasks[i]) {
          q._tasks[i] = null;
          if (t.abort) {
            try { t.abort(); }
            catch (e) { /* ignore */ }
          }
        }
      }
  
      q._active = NaN; // allow notification
      maybeNotify(q);
    }
  
    function maybeNotify(q) {
      if (!q._active && q._call) {
        var d = q._data;
        q._data = undefined; // allow gc
        q._call(q._error, d);
      }
    }
  
    function queue(concurrency) {
      return new Queue(arguments.length ? +concurrency : Infinity);
    }
  
    function constant$1(x) {
      return function constant() {
        return x;
      };
    }
  
    var epsilon$1 = 1e-12;
    var pi$2 = Math.PI;
    var halfPi$1 = pi$2 / 2;
    var tau$2 = 2 * pi$2;
  
    function arcInnerRadius(d) {
      return d.innerRadius;
    }
  
    function arcOuterRadius(d) {
      return d.outerRadius;
    }
  
    function arcStartAngle(d) {
      return d.startAngle;
    }
  
    function arcEndAngle(d) {
      return d.endAngle;
    }
  
    function arcPadAngle(d) {
      return d && d.padAngle; // Note: optional!
    }
  
    function asin(x) {
      return x >= 1 ? halfPi$1 : x <= -1 ? -halfPi$1 : Math.asin(x);
    }
  
    function intersect(x0, y0, x1, y1, x2, y2, x3, y3) {
      var x10 = x1 - x0, y10 = y1 - y0,
          x32 = x3 - x2, y32 = y3 - y2,
          t = (x32 * (y0 - y2) - y32 * (x0 - x2)) / (y32 * x10 - x32 * y10);
      return [x0 + t * x10, y0 + t * y10];
    }
  
    // Compute perpendicular offset line of length rc.
    // http://mathworld.wolfram.com/Circle-LineIntersection.html
    function cornerTangents(x0, y0, x1, y1, r1, rc, cw) {
      var x01 = x0 - x1,
          y01 = y0 - y1,
          lo = (cw ? rc : -rc) / Math.sqrt(x01 * x01 + y01 * y01),
          ox = lo * y01,
          oy = -lo * x01,
          x11 = x0 + ox,
          y11 = y0 + oy,
          x10 = x1 + ox,
          y10 = y1 + oy,
          x00 = (x11 + x10) / 2,
          y00 = (y11 + y10) / 2,
          dx = x10 - x11,
          dy = y10 - y11,
          d2 = dx * dx + dy * dy,
          r = r1 - rc,
          D = x11 * y10 - x10 * y11,
          d = (dy < 0 ? -1 : 1) * Math.sqrt(Math.max(0, r * r * d2 - D * D)),
          cx0 = (D * dy - dx * d) / d2,
          cy0 = (-D * dx - dy * d) / d2,
          cx1 = (D * dy + dx * d) / d2,
          cy1 = (-D * dx + dy * d) / d2,
          dx0 = cx0 - x00,
          dy0 = cy0 - y00,
          dx1 = cx1 - x00,
          dy1 = cy1 - y00;
  
      // Pick the closer of the two intersection points.
      // TODO Is there a faster way to determine which intersection to use?
      if (dx0 * dx0 + dy0 * dy0 > dx1 * dx1 + dy1 * dy1) cx0 = cx1, cy0 = cy1;
  
      return {
        cx: cx0,
        cy: cy0,
        x01: -ox,
        y01: -oy,
        x11: cx0 * (r1 / r - 1),
        y11: cy0 * (r1 / r - 1)
      };
    }
  
    function arc() {
      var innerRadius = arcInnerRadius,
          outerRadius = arcOuterRadius,
          cornerRadius = constant$1(0),
          padRadius = null,
          startAngle = arcStartAngle,
          endAngle = arcEndAngle,
          padAngle = arcPadAngle,
          context = null;
  
      function arc() {
        var buffer,
            r,
            r0 = +innerRadius.apply(this, arguments),
            r1 = +outerRadius.apply(this, arguments),
            a0 = startAngle.apply(this, arguments) - halfPi$1,
            a1 = endAngle.apply(this, arguments) - halfPi$1,
            da = Math.abs(a1 - a0),
            cw = a1 > a0;
  
        if (!context) context = buffer = path();
  
        // Ensure that the outer radius is always larger than the inner radius.
        if (r1 < r0) r = r1, r1 = r0, r0 = r;
  
        // Is it a point?
        if (!(r1 > epsilon$1)) context.moveTo(0, 0);
  
        // Or is it a circle or annulus?
        else if (da > tau$2 - epsilon$1) {
          context.moveTo(r1 * Math.cos(a0), r1 * Math.sin(a0));
          context.arc(0, 0, r1, a0, a1, !cw);
          if (r0 > epsilon$1) {
            context.moveTo(r0 * Math.cos(a1), r0 * Math.sin(a1));
            context.arc(0, 0, r0, a1, a0, cw);
          }
        }
  
        // Or is it a circular or annular sector?
        else {
          var a01 = a0,
              a11 = a1,
              a00 = a0,
              a10 = a1,
              da0 = da,
              da1 = da,
              ap = padAngle.apply(this, arguments) / 2,
              rp = (ap > epsilon$1) && (padRadius ? +padRadius.apply(this, arguments) : Math.sqrt(r0 * r0 + r1 * r1)),
              rc = Math.min(Math.abs(r1 - r0) / 2, +cornerRadius.apply(this, arguments)),
              rc0 = rc,
              rc1 = rc,
              t0,
              t1;
  
          // Apply padding? Note that since r1 ≥ r0, da1 ≥ da0.
          if (rp > epsilon$1) {
            var p0 = asin(rp / r0 * Math.sin(ap)),
                p1 = asin(rp / r1 * Math.sin(ap));
            if ((da0 -= p0 * 2) > epsilon$1) p0 *= (cw ? 1 : -1), a00 += p0, a10 -= p0;
            else da0 = 0, a00 = a10 = (a0 + a1) / 2;
            if ((da1 -= p1 * 2) > epsilon$1) p1 *= (cw ? 1 : -1), a01 += p1, a11 -= p1;
            else da1 = 0, a01 = a11 = (a0 + a1) / 2;
          }
  
          var x01 = r1 * Math.cos(a01),
              y01 = r1 * Math.sin(a01),
              x10 = r0 * Math.cos(a10),
              y10 = r0 * Math.sin(a10);
  
          // Apply rounded corners?
          if (rc > epsilon$1) {
            var x11 = r1 * Math.cos(a11),
                y11 = r1 * Math.sin(a11),
                x00 = r0 * Math.cos(a00),
                y00 = r0 * Math.sin(a00);
  
            // Restrict the corner radius according to the sector angle.
            if (da < pi$2) {
              var oc = da0 > epsilon$1 ? intersect(x01, y01, x00, y00, x11, y11, x10, y10) : [x10, y10],
                  ax = x01 - oc[0],
                  ay = y01 - oc[1],
                  bx = x11 - oc[0],
                  by = y11 - oc[1],
                  kc = 1 / Math.sin(Math.acos((ax * bx + ay * by) / (Math.sqrt(ax * ax + ay * ay) * Math.sqrt(bx * bx + by * by))) / 2),
                  lc = Math.sqrt(oc[0] * oc[0] + oc[1] * oc[1]);
              rc0 = Math.min(rc, (r0 - lc) / (kc - 1));
              rc1 = Math.min(rc, (r1 - lc) / (kc + 1));
            }
          }
  
          // Is the sector collapsed to a line?
          if (!(da1 > epsilon$1)) context.moveTo(x01, y01);
  
          // Does the sector’s outer ring have rounded corners?
          else if (rc1 > epsilon$1) {
            t0 = cornerTangents(x00, y00, x01, y01, r1, rc1, cw);
            t1 = cornerTangents(x11, y11, x10, y10, r1, rc1, cw);
  
            context.moveTo(t0.cx + t0.x01, t0.cy + t0.y01);
  
            // Have the corners merged?
            if (rc1 < rc) context.arc(t0.cx, t0.cy, rc1, Math.atan2(t0.y01, t0.x01), Math.atan2(t1.y01, t1.x01), !cw);
  
            // Otherwise, draw the two corners and the ring.
            else {
              context.arc(t0.cx, t0.cy, rc1, Math.atan2(t0.y01, t0.x01), Math.atan2(t0.y11, t0.x11), !cw);
              context.arc(0, 0, r1, Math.atan2(t0.cy + t0.y11, t0.cx + t0.x11), Math.atan2(t1.cy + t1.y11, t1.cx + t1.x11), !cw);
              context.arc(t1.cx, t1.cy, rc1, Math.atan2(t1.y11, t1.x11), Math.atan2(t1.y01, t1.x01), !cw);
            }
          }
  
          // Or is the outer ring just a circular arc?
          else context.moveTo(x01, y01), context.arc(0, 0, r1, a01, a11, !cw);
  
          // Is there no inner ring, and it’s a circular sector?
          // Or perhaps it’s an annular sector collapsed due to padding?
          if (!(r0 > epsilon$1) || !(da0 > epsilon$1)) context.lineTo(x10, y10);
  
          // Does the sector’s inner ring (or point) have rounded corners?
          else if (rc0 > epsilon$1) {
            t0 = cornerTangents(x10, y10, x11, y11, r0, -rc0, cw);
            t1 = cornerTangents(x01, y01, x00, y00, r0, -rc0, cw);
  
            context.lineTo(t0.cx + t0.x01, t0.cy + t0.y01);
  
            // Have the corners merged?
            if (rc0 < rc) context.arc(t0.cx, t0.cy, rc0, Math.atan2(t0.y01, t0.x01), Math.atan2(t1.y01, t1.x01), !cw);
  
            // Otherwise, draw the two corners and the ring.
            else {
              context.arc(t0.cx, t0.cy, rc0, Math.atan2(t0.y01, t0.x01), Math.atan2(t0.y11, t0.x11), !cw);
              context.arc(0, 0, r0, Math.atan2(t0.cy + t0.y11, t0.cx + t0.x11), Math.atan2(t1.cy + t1.y11, t1.cx + t1.x11), cw);
              context.arc(t1.cx, t1.cy, rc0, Math.atan2(t1.y11, t1.x11), Math.atan2(t1.y01, t1.x01), !cw);
            }
          }
  
          // Or is the inner ring just a circular arc?
          else context.arc(0, 0, r0, a10, a00, cw);
        }
  
        context.closePath();
  
        if (buffer) return context = null, buffer + "" || null;
      }
  
      arc.centroid = function() {
        var r = (+innerRadius.apply(this, arguments) + +outerRadius.apply(this, arguments)) / 2,
            a = (+startAngle.apply(this, arguments) + +endAngle.apply(this, arguments)) / 2 - pi$2 / 2;
        return [Math.cos(a) * r, Math.sin(a) * r];
      };
  
      arc.innerRadius = function(_) {
        return arguments.length ? (innerRadius = typeof _ === "function" ? _ : constant$1(+_), arc) : innerRadius;
      };
  
      arc.outerRadius = function(_) {
        return arguments.length ? (outerRadius = typeof _ === "function" ? _ : constant$1(+_), arc) : outerRadius;
      };
  
      arc.cornerRadius = function(_) {
        return arguments.length ? (cornerRadius = typeof _ === "function" ? _ : constant$1(+_), arc) : cornerRadius;
      };
  
      arc.padRadius = function(_) {
        return arguments.length ? (padRadius = _ == null ? null : typeof _ === "function" ? _ : constant$1(+_), arc) : padRadius;
      };
  
      arc.startAngle = function(_) {
        return arguments.length ? (startAngle = typeof _ === "function" ? _ : constant$1(+_), arc) : startAngle;
      };
  
      arc.endAngle = function(_) {
        return arguments.length ? (endAngle = typeof _ === "function" ? _ : constant$1(+_), arc) : endAngle;
      };
  
      arc.padAngle = function(_) {
        return arguments.length ? (padAngle = typeof _ === "function" ? _ : constant$1(+_), arc) : padAngle;
      };
  
      arc.context = function(_) {
        return arguments.length ? ((context = _ == null ? null : _), arc) : context;
      };
  
      return arc;
    }
  
    function Linear(context) {
      this._context = context;
    }
  
    Linear.prototype = {
      areaStart: function() {
        this._line = 0;
      },
      areaEnd: function() {
        this._line = NaN;
      },
      lineStart: function() {
        this._point = 0;
      },
      lineEnd: function() {
        if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
        this._line = 1 - this._line;
      },
      point: function(x, y) {
        x = +x, y = +y;
        switch (this._point) {
          case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
          case 1: this._point = 2; // proceed
          default: this._context.lineTo(x, y); break;
        }
      }
    };
  
    function curveLinear(context) {
      return new Linear(context);
    }
  
    function x(p) {
      return p[0];
    }
  
    function y(p) {
      return p[1];
    }
  
    function line() {
      var x$$ = x,
          y$$ = y,
          defined = constant$1(true),
          context = null,
          curve = curveLinear,
          output = null;
  
      function line(data) {
        var i,
            n = data.length,
            d,
            defined0 = false,
            buffer;
  
        if (context == null) output = curve(buffer = path());
  
        for (i = 0; i <= n; ++i) {
          if (!(i < n && defined(d = data[i], i, data)) === defined0) {
            if (defined0 = !defined0) output.lineStart();
            else output.lineEnd();
          }
          if (defined0) output.point(+x$$(d, i, data), +y$$(d, i, data));
        }
  
        if (buffer) return output = null, buffer + "" || null;
      }
  
      line.x = function(_) {
        return arguments.length ? (x$$ = typeof _ === "function" ? _ : constant$1(+_), line) : x$$;
      };
  
      line.y = function(_) {
        return arguments.length ? (y$$ = typeof _ === "function" ? _ : constant$1(+_), line) : y$$;
      };
  
      line.defined = function(_) {
        return arguments.length ? (defined = typeof _ === "function" ? _ : constant$1(!!_), line) : defined;
      };
  
      line.curve = function(_) {
        return arguments.length ? (curve = _, context != null && (output = curve(context)), line) : curve;
      };
  
      line.context = function(_) {
        return arguments.length ? (_ == null ? context = output = null : output = curve(context = _), line) : context;
      };
  
      return line;
    }
  
    function area$1() {
      var x0 = x,
          x1 = null,
          y0 = constant$1(0),
          y1 = y,
          defined = constant$1(true),
          context = null,
          curve = curveLinear,
          output = null;
  
      function area(data) {
        var i,
            j,
            k,
            n = data.length,
            d,
            defined0 = false,
            buffer,
            x0z = new Array(n),
            y0z = new Array(n);
  
        if (context == null) output = curve(buffer = path());
  
        for (i = 0; i <= n; ++i) {
          if (!(i < n && defined(d = data[i], i, data)) === defined0) {
            if (defined0 = !defined0) {
              j = i;
              output.areaStart();
              output.lineStart();
            } else {
              output.lineEnd();
              output.lineStart();
              for (k = i - 1; k >= j; --k) {
                output.point(x0z[k], y0z[k]);
              }
              output.lineEnd();
              output.areaEnd();
            }
          }
          if (defined0) {
            x0z[i] = +x0(d, i, data), y0z[i] = +y0(d, i, data);
            output.point(x1 ? +x1(d, i, data) : x0z[i], y1 ? +y1(d, i, data) : y0z[i]);
          }
        }
  
        if (buffer) return output = null, buffer + "" || null;
      }
  
      function arealine() {
        return line().defined(defined).curve(curve).context(context);
      }
  
      area.x = function(_) {
        return arguments.length ? (x0 = typeof _ === "function" ? _ : constant$1(+_), x1 = null, area) : x0;
      };
  
      area.x0 = function(_) {
        return arguments.length ? (x0 = typeof _ === "function" ? _ : constant$1(+_), area) : x0;
      };
  
      area.x1 = function(_) {
        return arguments.length ? (x1 = _ == null ? null : typeof _ === "function" ? _ : constant$1(+_), area) : x1;
      };
  
      area.y = function(_) {
        return arguments.length ? (y0 = typeof _ === "function" ? _ : constant$1(+_), y1 = null, area) : y0;
      };
  
      area.y0 = function(_) {
        return arguments.length ? (y0 = typeof _ === "function" ? _ : constant$1(+_), area) : y0;
      };
  
      area.y1 = function(_) {
        return arguments.length ? (y1 = _ == null ? null : typeof _ === "function" ? _ : constant$1(+_), area) : y1;
      };
  
      area.lineX0 =
      area.lineY0 = function() {
        return arealine().x(x0).y(y0);
      };
  
      area.lineY1 = function() {
        return arealine().x(x0).y(y1);
      };
  
      area.lineX1 = function() {
        return arealine().x(x1).y(y0);
      };
  
      area.defined = function(_) {
        return arguments.length ? (defined = typeof _ === "function" ? _ : constant$1(!!_), area) : defined;
      };
  
      area.curve = function(_) {
        return arguments.length ? (curve = _, context != null && (output = curve(context)), area) : curve;
      };
  
      area.context = function(_) {
        return arguments.length ? (_ == null ? context = output = null : output = curve(context = _), area) : context;
      };
  
      return area;
    }
  
    function descending$1(a, b) {
      return b < a ? -1 : b > a ? 1 : b >= a ? 0 : NaN;
    }
  
    function identity$1(d) {
      return d;
    }
  
    function pie() {
      var value = identity$1,
          sortValues = descending$1,
          sort = null,
          startAngle = constant$1(0),
          endAngle = constant$1(tau$2),
          padAngle = constant$1(0);
  
      function pie(data) {
        var i,
            n = data.length,
            j,
            k,
            sum = 0,
            index = new Array(n),
            arcs = new Array(n),
            a0 = +startAngle.apply(this, arguments),
            da = Math.min(tau$2, Math.max(-tau$2, endAngle.apply(this, arguments) - a0)),
            a1,
            p = Math.min(Math.abs(da) / n, padAngle.apply(this, arguments)),
            pa = p * (da < 0 ? -1 : 1),
            v;
  
        for (i = 0; i < n; ++i) {
          if ((v = arcs[index[i] = i] = +value(data[i], i, data)) > 0) {
            sum += v;
          }
        }
  
        // Optionally sort the arcs by previously-computed values or by data.
        if (sortValues != null) index.sort(function(i, j) { return sortValues(arcs[i], arcs[j]); });
        else if (sort != null) index.sort(function(i, j) { return sort(data[i], data[j]); });
  
        // Compute the arcs! They are stored in the original data's order.
        for (i = 0, k = sum ? (da - n * pa) / sum : 0; i < n; ++i, a0 = a1) {
          j = index[i], v = arcs[j], a1 = a0 + (v > 0 ? v * k : 0) + pa, arcs[j] = {
            data: data[j],
            index: i,
            value: v,
            startAngle: a0,
            endAngle: a1,
            padAngle: p
          };
        }
  
        return arcs;
      }
  
      pie.value = function(_) {
        return arguments.length ? (value = typeof _ === "function" ? _ : constant$1(+_), pie) : value;
      };
  
      pie.sortValues = function(_) {
        return arguments.length ? (sortValues = _, sort = null, pie) : sortValues;
      };
  
      pie.sort = function(_) {
        return arguments.length ? (sort = _, sortValues = null, pie) : sort;
      };
  
      pie.startAngle = function(_) {
        return arguments.length ? (startAngle = typeof _ === "function" ? _ : constant$1(+_), pie) : startAngle;
      };
  
      pie.endAngle = function(_) {
        return arguments.length ? (endAngle = typeof _ === "function" ? _ : constant$1(+_), pie) : endAngle;
      };
  
      pie.padAngle = function(_) {
        return arguments.length ? (padAngle = typeof _ === "function" ? _ : constant$1(+_), pie) : padAngle;
      };
  
      return pie;
    }
  
    var curveRadialLinear = curveRadial(curveLinear);
  
    function Radial(curve) {
      this._curve = curve;
    }
  
    Radial.prototype = {
      areaStart: function() {
        this._curve.areaStart();
      },
      areaEnd: function() {
        this._curve.areaEnd();
      },
      lineStart: function() {
        this._curve.lineStart();
      },
      lineEnd: function() {
        this._curve.lineEnd();
      },
      point: function(a, r) {
        this._curve.point(r * Math.sin(a), r * -Math.cos(a));
      }
    };
  
    function curveRadial(curve) {
  
      function radial(context) {
        return new Radial(curve(context));
      }
  
      radial._curve = curve;
  
      return radial;
    }
  
    function radialLine(l) {
      var c = l.curve;
  
      l.angle = l.x, delete l.x;
      l.radius = l.y, delete l.y;
  
      l.curve = function(_) {
        return arguments.length ? c(curveRadial(_)) : c()._curve;
      };
  
      return l;
    }
  
    function radialLine$1() {
      return radialLine(line().curve(curveRadialLinear));
    }
  
    function radialArea() {
      var a = area$1().curve(curveRadialLinear),
          c = a.curve,
          x0 = a.lineX0,
          x1 = a.lineX1,
          y0 = a.lineY0,
          y1 = a.lineY1;
  
      a.angle = a.x, delete a.x;
      a.startAngle = a.x0, delete a.x0;
      a.endAngle = a.x1, delete a.x1;
      a.radius = a.y, delete a.y;
      a.innerRadius = a.y0, delete a.y0;
      a.outerRadius = a.y1, delete a.y1;
      a.lineStartAngle = function() { return radialLine(x0()); }, delete a.lineX0;
      a.lineEndAngle = function() { return radialLine(x1()); }, delete a.lineX1;
      a.lineInnerRadius = function() { return radialLine(y0()); }, delete a.lineY0;
      a.lineOuterRadius = function() { return radialLine(y1()); }, delete a.lineY1;
  
      a.curve = function(_) {
        return arguments.length ? c(curveRadial(_)) : c()._curve;
      };
  
      return a;
    }
  
    var circle = {
      draw: function(context, size) {
        var r = Math.sqrt(size / pi$2);
        context.moveTo(r, 0);
        context.arc(0, 0, r, 0, tau$2);
      }
    };
  
    var cross$1 = {
      draw: function(context, size) {
        var r = Math.sqrt(size / 5) / 2;
        context.moveTo(-3 * r, -r);
        context.lineTo(-r, -r);
        context.lineTo(-r, -3 * r);
        context.lineTo(r, -3 * r);
        context.lineTo(r, -r);
        context.lineTo(3 * r, -r);
        context.lineTo(3 * r, r);
        context.lineTo(r, r);
        context.lineTo(r, 3 * r);
        context.lineTo(-r, 3 * r);
        context.lineTo(-r, r);
        context.lineTo(-3 * r, r);
        context.closePath();
      }
    };
  
    var tan30 = Math.sqrt(1 / 3);
    var tan30_2 = tan30 * 2;
    var diamond = {
      draw: function(context, size) {
        var y = Math.sqrt(size / tan30_2),
            x = y * tan30;
        context.moveTo(0, -y);
        context.lineTo(x, 0);
        context.lineTo(0, y);
        context.lineTo(-x, 0);
        context.closePath();
      }
    };
  
    var ka = 0.89081309152928522810;
    var kr = Math.sin(pi$2 / 10) / Math.sin(7 * pi$2 / 10);
    var kx = Math.sin(tau$2 / 10) * kr;
    var ky = -Math.cos(tau$2 / 10) * kr;
    var star = {
      draw: function(context, size) {
        var r = Math.sqrt(size * ka),
            x = kx * r,
            y = ky * r;
        context.moveTo(0, -r);
        context.lineTo(x, y);
        for (var i = 1; i < 5; ++i) {
          var a = tau$2 * i / 5,
              c = Math.cos(a),
              s = Math.sin(a);
          context.lineTo(s * r, -c * r);
          context.lineTo(c * x - s * y, s * x + c * y);
        }
        context.closePath();
      }
    };
  
    var square = {
      draw: function(context, size) {
        var w = Math.sqrt(size),
            x = -w / 2;
        context.rect(x, x, w, w);
      }
    };
  
    var sqrt3 = Math.sqrt(3);
  
    var triangle = {
      draw: function(context, size) {
        var y = -Math.sqrt(size / (sqrt3 * 3));
        context.moveTo(0, y * 2);
        context.lineTo(-sqrt3 * y, -y);
        context.lineTo(sqrt3 * y, -y);
        context.closePath();
      }
    };
  
    var c = -0.5;
    var s = Math.sqrt(3) / 2;
    var k = 1 / Math.sqrt(12);
    var a = (k / 2 + 1) * 3;
    var wye = {
      draw: function(context, size) {
        var r = Math.sqrt(size / a),
            x0 = r / 2,
            y0 = r * k,
            x1 = x0,
            y1 = r * k + r,
            x2 = -x1,
            y2 = y1;
        context.moveTo(x0, y0);
        context.lineTo(x1, y1);
        context.lineTo(x2, y2);
        context.lineTo(c * x0 - s * y0, s * x0 + c * y0);
        context.lineTo(c * x1 - s * y1, s * x1 + c * y1);
        context.lineTo(c * x2 - s * y2, s * x2 + c * y2);
        context.lineTo(c * x0 + s * y0, c * y0 - s * x0);
        context.lineTo(c * x1 + s * y1, c * y1 - s * x1);
        context.lineTo(c * x2 + s * y2, c * y2 - s * x2);
        context.closePath();
      }
    };
  
    var symbols = [
      circle,
      cross$1,
      diamond,
      square,
      star,
      triangle,
      wye
    ];
  
    function symbol() {
      var type = constant$1(circle),
          size = constant$1(64),
          context = null;
  
      function symbol() {
        var buffer;
        if (!context) context = buffer = path();
        type.apply(this, arguments).draw(context, +size.apply(this, arguments));
        if (buffer) return context = null, buffer + "" || null;
      }
  
      symbol.type = function(_) {
        return arguments.length ? (type = typeof _ === "function" ? _ : constant$1(_), symbol) : type;
      };
  
      symbol.size = function(_) {
        return arguments.length ? (size = typeof _ === "function" ? _ : constant$1(+_), symbol) : size;
      };
  
      symbol.context = function(_) {
        return arguments.length ? (context = _ == null ? null : _, symbol) : context;
      };
  
      return symbol;
    }
  
    function noop() {}
  
    function point(that, x, y) {
      that._context.bezierCurveTo(
        (2 * that._x0 + that._x1) / 3,
        (2 * that._y0 + that._y1) / 3,
        (that._x0 + 2 * that._x1) / 3,
        (that._y0 + 2 * that._y1) / 3,
        (that._x0 + 4 * that._x1 + x) / 6,
        (that._y0 + 4 * that._y1 + y) / 6
      );
    }
  
    function Basis(context) {
      this._context = context;
    }
  
    Basis.prototype = {
      areaStart: function() {
        this._line = 0;
      },
      areaEnd: function() {
        this._line = NaN;
      },
      lineStart: function() {
        this._x0 = this._x1 =
        this._y0 = this._y1 = NaN;
        this._point = 0;
      },
      lineEnd: function() {
        switch (this._point) {
          case 3: point(this, this._x1, this._y1); // proceed
          case 2: this._context.lineTo(this._x1, this._y1); break;
        }
        if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
        this._line = 1 - this._line;
      },
      point: function(x, y) {
        x = +x, y = +y;
        switch (this._point) {
          case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
          case 1: this._point = 2; break;
          case 2: this._point = 3; this._context.lineTo((5 * this._x0 + this._x1) / 6, (5 * this._y0 + this._y1) / 6); // proceed
          default: point(this, x, y); break;
        }
        this._x0 = this._x1, this._x1 = x;
        this._y0 = this._y1, this._y1 = y;
      }
    };
  
    function basis(context) {
      return new Basis(context);
    }
  
    function BasisClosed(context) {
      this._context = context;
    }
  
    BasisClosed.prototype = {
      areaStart: noop,
      areaEnd: noop,
      lineStart: function() {
        this._x0 = this._x1 = this._x2 = this._x3 = this._x4 =
        this._y0 = this._y1 = this._y2 = this._y3 = this._y4 = NaN;
        this._point = 0;
      },
      lineEnd: function() {
        switch (this._point) {
          case 1: {
            this._context.moveTo(this._x2, this._y2);
            this._context.closePath();
            break;
          }
          case 2: {
            this._context.moveTo((this._x2 + 2 * this._x3) / 3, (this._y2 + 2 * this._y3) / 3);
            this._context.lineTo((this._x3 + 2 * this._x2) / 3, (this._y3 + 2 * this._y2) / 3);
            this._context.closePath();
            break;
          }
          case 3: {
            this.point(this._x2, this._y2);
            this.point(this._x3, this._y3);
            this.point(this._x4, this._y4);
            break;
          }
        }
      },
      point: function(x, y) {
        x = +x, y = +y;
        switch (this._point) {
          case 0: this._point = 1; this._x2 = x, this._y2 = y; break;
          case 1: this._point = 2; this._x3 = x, this._y3 = y; break;
          case 2: this._point = 3; this._x4 = x, this._y4 = y; this._context.moveTo((this._x0 + 4 * this._x1 + x) / 6, (this._y0 + 4 * this._y1 + y) / 6); break;
          default: point(this, x, y); break;
        }
        this._x0 = this._x1, this._x1 = x;
        this._y0 = this._y1, this._y1 = y;
      }
    };
  
    function basisClosed(context) {
      return new BasisClosed(context);
    }
  
    function BasisOpen(context) {
      this._context = context;
    }
  
    BasisOpen.prototype = {
      areaStart: function() {
        this._line = 0;
      },
      areaEnd: function() {
        this._line = NaN;
      },
      lineStart: function() {
        this._x0 = this._x1 =
        this._y0 = this._y1 = NaN;
        this._point = 0;
      },
      lineEnd: function() {
        if (this._line || (this._line !== 0 && this._point === 3)) this._context.closePath();
        this._line = 1 - this._line;
      },
      point: function(x, y) {
        x = +x, y = +y;
        switch (this._point) {
          case 0: this._point = 1; break;
          case 1: this._point = 2; break;
          case 2: this._point = 3; var x0 = (this._x0 + 4 * this._x1 + x) / 6, y0 = (this._y0 + 4 * this._y1 + y) / 6; this._line ? this._context.lineTo(x0, y0) : this._context.moveTo(x0, y0); break;
          case 3: this._point = 4; // proceed
          default: point(this, x, y); break;
        }
        this._x0 = this._x1, this._x1 = x;
        this._y0 = this._y1, this._y1 = y;
      }
    };
  
    function basisOpen(context) {
      return new BasisOpen(context);
    }
  
    function Bundle(context, beta) {
      this._basis = new Basis(context);
      this._beta = beta;
    }
  
    Bundle.prototype = {
      lineStart: function() {
        this._x = [];
        this._y = [];
        this._basis.lineStart();
      },
      lineEnd: function() {
        var x = this._x,
            y = this._y,
            j = x.length - 1;
  
        if (j > 0) {
          var x0 = x[0],
              y0 = y[0],
              dx = x[j] - x0,
              dy = y[j] - y0,
              i = -1,
              t;
  
          while (++i <= j) {
            t = i / j;
            this._basis.point(
              this._beta * x[i] + (1 - this._beta) * (x0 + t * dx),
              this._beta * y[i] + (1 - this._beta) * (y0 + t * dy)
            );
          }
        }
  
        this._x = this._y = null;
        this._basis.lineEnd();
      },
      point: function(x, y) {
        this._x.push(+x);
        this._y.push(+y);
      }
    };
  
    var bundle = (function custom(beta) {
  
      function bundle(context) {
        return beta === 1 ? new Basis(context) : new Bundle(context, beta);
      }
  
      bundle.beta = function(beta) {
        return custom(+beta);
      };
  
      return bundle;
    })(0.85);
  
    function point$1(that, x, y) {
      that._context.bezierCurveTo(
        that._x1 + that._k * (that._x2 - that._x0),
        that._y1 + that._k * (that._y2 - that._y0),
        that._x2 + that._k * (that._x1 - x),
        that._y2 + that._k * (that._y1 - y),
        that._x2,
        that._y2
      );
    }
  
    function Cardinal(context, tension) {
      this._context = context;
      this._k = (1 - tension) / 6;
    }
  
    Cardinal.prototype = {
      areaStart: function() {
        this._line = 0;
      },
      areaEnd: function() {
        this._line = NaN;
      },
      lineStart: function() {
        this._x0 = this._x1 = this._x2 =
        this._y0 = this._y1 = this._y2 = NaN;
        this._point = 0;
      },
      lineEnd: function() {
        switch (this._point) {
          case 2: this._context.lineTo(this._x2, this._y2); break;
          case 3: point$1(this, this._x1, this._y1); break;
        }
        if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
        this._line = 1 - this._line;
      },
      point: function(x, y) {
        x = +x, y = +y;
        switch (this._point) {
          case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
          case 1: this._point = 2; this._x1 = x, this._y1 = y; break;
          case 2: this._point = 3; // proceed
          default: point$1(this, x, y); break;
        }
        this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
        this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
      }
    };
  
    var cardinal = (function custom(tension) {
  
      function cardinal(context) {
        return new Cardinal(context, tension);
      }
  
      cardinal.tension = function(tension) {
        return custom(+tension);
      };
  
      return cardinal;
    })(0);
  
    function CardinalClosed(context, tension) {
      this._context = context;
      this._k = (1 - tension) / 6;
    }
  
    CardinalClosed.prototype = {
      areaStart: noop,
      areaEnd: noop,
      lineStart: function() {
        this._x0 = this._x1 = this._x2 = this._x3 = this._x4 = this._x5 =
        this._y0 = this._y1 = this._y2 = this._y3 = this._y4 = this._y5 = NaN;
        this._point = 0;
      },
      lineEnd: function() {
        switch (this._point) {
          case 1: {
            this._context.moveTo(this._x3, this._y3);
            this._context.closePath();
            break;
          }
          case 2: {
            this._context.lineTo(this._x3, this._y3);
            this._context.closePath();
            break;
          }
          case 3: {
            this.point(this._x3, this._y3);
            this.point(this._x4, this._y4);
            this.point(this._x5, this._y5);
            break;
          }
        }
      },
      point: function(x, y) {
        x = +x, y = +y;
        switch (this._point) {
          case 0: this._point = 1; this._x3 = x, this._y3 = y; break;
          case 1: this._point = 2; this._context.moveTo(this._x4 = x, this._y4 = y); break;
          case 2: this._point = 3; this._x5 = x, this._y5 = y; break;
          default: point$1(this, x, y); break;
        }
        this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
        this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
      }
    };
  
    var cardinalClosed = (function custom(tension) {
  
      function cardinal(context) {
        return new CardinalClosed(context, tension);
      }
  
      cardinal.tension = function(tension) {
        return custom(+tension);
      };
  
      return cardinal;
    })(0);
  
    function CardinalOpen(context, tension) {
      this._context = context;
      this._k = (1 - tension) / 6;
    }
  
    CardinalOpen.prototype = {
      areaStart: function() {
        this._line = 0;
      },
      areaEnd: function() {
        this._line = NaN;
      },
      lineStart: function() {
        this._x0 = this._x1 = this._x2 =
        this._y0 = this._y1 = this._y2 = NaN;
        this._point = 0;
      },
      lineEnd: function() {
        if (this._line || (this._line !== 0 && this._point === 3)) this._context.closePath();
        this._line = 1 - this._line;
      },
      point: function(x, y) {
        x = +x, y = +y;
        switch (this._point) {
          case 0: this._point = 1; break;
          case 1: this._point = 2; break;
          case 2: this._point = 3; this._line ? this._context.lineTo(this._x2, this._y2) : this._context.moveTo(this._x2, this._y2); break;
          case 3: this._point = 4; // proceed
          default: point$1(this, x, y); break;
        }
        this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
        this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
      }
    };
  
    var cardinalOpen = (function custom(tension) {
  
      function cardinal(context) {
        return new CardinalOpen(context, tension);
      }
  
      cardinal.tension = function(tension) {
        return custom(+tension);
      };
  
      return cardinal;
    })(0);
  
    function point$2(that, x, y) {
      var x1 = that._x1,
          y1 = that._y1,
          x2 = that._x2,
          y2 = that._y2;
  
      if (that._l01_a > epsilon$1) {
        var a = 2 * that._l01_2a + 3 * that._l01_a * that._l12_a + that._l12_2a,
            n = 3 * that._l01_a * (that._l01_a + that._l12_a);
        x1 = (x1 * a - that._x0 * that._l12_2a + that._x2 * that._l01_2a) / n;
        y1 = (y1 * a - that._y0 * that._l12_2a + that._y2 * that._l01_2a) / n;
      }
  
      if (that._l23_a > epsilon$1) {
        var b = 2 * that._l23_2a + 3 * that._l23_a * that._l12_a + that._l12_2a,
            m = 3 * that._l23_a * (that._l23_a + that._l12_a);
        x2 = (x2 * b + that._x1 * that._l23_2a - x * that._l12_2a) / m;
        y2 = (y2 * b + that._y1 * that._l23_2a - y * that._l12_2a) / m;
      }
  
      that._context.bezierCurveTo(x1, y1, x2, y2, that._x2, that._y2);
    }
  
    function CatmullRom(context, alpha) {
      this._context = context;
      this._alpha = alpha;
    }
  
    CatmullRom.prototype = {
      areaStart: function() {
        this._line = 0;
      },
      areaEnd: function() {
        this._line = NaN;
      },
      lineStart: function() {
        this._x0 = this._x1 = this._x2 =
        this._y0 = this._y1 = this._y2 = NaN;
        this._l01_a = this._l12_a = this._l23_a =
        this._l01_2a = this._l12_2a = this._l23_2a =
        this._point = 0;
      },
      lineEnd: function() {
        switch (this._point) {
          case 2: this._context.lineTo(this._x2, this._y2); break;
          case 3: this.point(this, this._x2, this._y2); break;
        }
        if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
        this._line = 1 - this._line;
      },
      point: function(x, y) {
        x = +x, y = +y;
  
        if (this._point) {
          var x23 = this._x2 - x,
              y23 = this._y2 - y;
          this._l23_a = Math.sqrt(this._l23_2a = Math.pow(x23 * x23 + y23 * y23, this._alpha));
        }
  
        switch (this._point) {
          case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
          case 1: this._point = 2; break;
          case 2: this._point = 3; // proceed
          default: point$2(this, x, y); break;
        }
  
        this._l01_a = this._l12_a, this._l12_a = this._l23_a;
        this._l01_2a = this._l12_2a, this._l12_2a = this._l23_2a;
        this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
        this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
      }
    };
  
    var catmullRom = (function custom(alpha) {
  
      function catmullRom(context) {
        return alpha ? new CatmullRom(context, alpha) : new Cardinal(context, 0);
      }
  
      catmullRom.alpha = function(alpha) {
        return custom(+alpha);
      };
  
      return catmullRom;
    })(0.5);
  
    function CatmullRomClosed(context, alpha) {
      this._context = context;
      this._alpha = alpha;
    }
  
    CatmullRomClosed.prototype = {
      areaStart: noop,
      areaEnd: noop,
      lineStart: function() {
        this._x0 = this._x1 = this._x2 = this._x3 = this._x4 = this._x5 =
        this._y0 = this._y1 = this._y2 = this._y3 = this._y4 = this._y5 = NaN;
        this._l01_a = this._l12_a = this._l23_a =
        this._l01_2a = this._l12_2a = this._l23_2a =
        this._point = 0;
      },
      lineEnd: function() {
        switch (this._point) {
          case 1: {
            this._context.moveTo(this._x3, this._y3);
            this._context.closePath();
            break;
          }
          case 2: {
            this._context.lineTo(this._x3, this._y3);
            this._context.closePath();
            break;
          }
          case 3: {
            this.point(this._x3, this._y3);
            this.point(this._x4, this._y4);
            this.point(this._x5, this._y5);
            break;
          }
        }
      },
      point: function(x, y) {
        x = +x, y = +y;
  
        if (this._point) {
          var x23 = this._x2 - x,
              y23 = this._y2 - y;
          this._l23_a = Math.sqrt(this._l23_2a = Math.pow(x23 * x23 + y23 * y23, this._alpha));
        }
  
        switch (this._point) {
          case 0: this._point = 1; this._x3 = x, this._y3 = y; break;
          case 1: this._point = 2; this._context.moveTo(this._x4 = x, this._y4 = y); break;
          case 2: this._point = 3; this._x5 = x, this._y5 = y; break;
          default: point$2(this, x, y); break;
        }
  
        this._l01_a = this._l12_a, this._l12_a = this._l23_a;
        this._l01_2a = this._l12_2a, this._l12_2a = this._l23_2a;
        this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
        this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
      }
    };
  
    var catmullRomClosed = (function custom(alpha) {
  
      function catmullRom(context) {
        return alpha ? new CatmullRomClosed(context, alpha) : new CardinalClosed(context, 0);
      }
  
      catmullRom.alpha = function(alpha) {
        return custom(+alpha);
      };
  
      return catmullRom;
    })(0.5);
  
    function CatmullRomOpen(context, alpha) {
      this._context = context;
      this._alpha = alpha;
    }
  
    CatmullRomOpen.prototype = {
      areaStart: function() {
        this._line = 0;
      },
      areaEnd: function() {
        this._line = NaN;
      },
      lineStart: function() {
        this._x0 = this._x1 = this._x2 =
        this._y0 = this._y1 = this._y2 = NaN;
        this._l01_a = this._l12_a = this._l23_a =
        this._l01_2a = this._l12_2a = this._l23_2a =
        this._point = 0;
      },
      lineEnd: function() {
        if (this._line || (this._line !== 0 && this._point === 3)) this._context.closePath();
        this._line = 1 - this._line;
      },
      point: function(x, y) {
        x = +x, y = +y;
  
        if (this._point) {
          var x23 = this._x2 - x,
              y23 = this._y2 - y;
          this._l23_a = Math.sqrt(this._l23_2a = Math.pow(x23 * x23 + y23 * y23, this._alpha));
        }
  
        switch (this._point) {
          case 0: this._point = 1; break;
          case 1: this._point = 2; break;
          case 2: this._point = 3; this._line ? this._context.lineTo(this._x2, this._y2) : this._context.moveTo(this._x2, this._y2); break;
          case 3: this._point = 4; // proceed
          default: point$2(this, x, y); break;
        }
  
        this._l01_a = this._l12_a, this._l12_a = this._l23_a;
        this._l01_2a = this._l12_2a, this._l12_2a = this._l23_2a;
        this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
        this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
      }
    };
  
    var catmullRomOpen = (function custom(alpha) {
  
      function catmullRom(context) {
        return alpha ? new CatmullRomOpen(context, alpha) : new CardinalOpen(context, 0);
      }
  
      catmullRom.alpha = function(alpha) {
        return custom(+alpha);
      };
  
      return catmullRom;
    })(0.5);
  
    function LinearClosed(context) {
      this._context = context;
    }
  
    LinearClosed.prototype = {
      areaStart: noop,
      areaEnd: noop,
      lineStart: function() {
        this._point = 0;
      },
      lineEnd: function() {
        if (this._point) this._context.closePath();
      },
      point: function(x, y) {
        x = +x, y = +y;
        if (this._point) this._context.lineTo(x, y);
        else this._point = 1, this._context.moveTo(x, y);
      }
    };
  
    function linearClosed(context) {
      return new LinearClosed(context);
    }
  
    function sign(x) {
      return x < 0 ? -1 : 1;
    }
  
    // Calculate the slopes of the tangents (Hermite-type interpolation) based on
    // the following paper: Steffen, M. 1990. A Simple Method for Monotonic
    // Interpolation in One Dimension. Astronomy and Astrophysics, Vol. 239, NO.
    // NOV(II), P. 443, 1990.
    function slope3(that, x2, y2) {
      var h0 = that._x1 - that._x0,
          h1 = x2 - that._x1,
          s0 = (that._y1 - that._y0) / (h0 || h1 < 0 && -0),
          s1 = (y2 - that._y1) / (h1 || h0 < 0 && -0),
          p = (s0 * h1 + s1 * h0) / (h0 + h1);
      return (sign(s0) + sign(s1)) * Math.min(Math.abs(s0), Math.abs(s1), 0.5 * Math.abs(p)) || 0;
    }
  
    // Calculate a one-sided slope.
    function slope2(that, t) {
      var h = that._x1 - that._x0;
      return h ? (3 * (that._y1 - that._y0) / h - t) / 2 : t;
    }
  
    // According to https://en.wikipedia.org/wiki/Cubic_Hermite_spline#Representations
    // "you can express cubic Hermite interpolation in terms of cubic Bézier curves
    // with respect to the four values p0, p0 + m0 / 3, p1 - m1 / 3, p1".
    function point$3(that, t0, t1) {
      var x0 = that._x0,
          y0 = that._y0,
          x1 = that._x1,
          y1 = that._y1,
          dx = (x1 - x0) / 3;
      that._context.bezierCurveTo(x0 + dx, y0 + dx * t0, x1 - dx, y1 - dx * t1, x1, y1);
    }
  
    function MonotoneX(context) {
      this._context = context;
    }
  
    MonotoneX.prototype = {
      areaStart: function() {
        this._line = 0;
      },
      areaEnd: function() {
        this._line = NaN;
      },
      lineStart: function() {
        this._x0 = this._x1 =
        this._y0 = this._y1 =
        this._t0 = NaN;
        this._point = 0;
      },
      lineEnd: function() {
        switch (this._point) {
          case 2: this._context.lineTo(this._x1, this._y1); break;
          case 3: point$3(this, this._t0, slope2(this, this._t0)); break;
        }
        if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
        this._line = 1 - this._line;
      },
      point: function(x, y) {
        var t1 = NaN;
  
        x = +x, y = +y;
        if (x === this._x1 && y === this._y1) return; // Ignore coincident points.
        switch (this._point) {
          case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
          case 1: this._point = 2; break;
          case 2: this._point = 3; point$3(this, slope2(this, t1 = slope3(this, x, y)), t1); break;
          default: point$3(this, this._t0, t1 = slope3(this, x, y)); break;
        }
  
        this._x0 = this._x1, this._x1 = x;
        this._y0 = this._y1, this._y1 = y;
        this._t0 = t1;
      }
    }
  
    function MonotoneY(context) {
      this._context = new ReflectContext(context);
    }
  
    (MonotoneY.prototype = Object.create(MonotoneX.prototype)).point = function(x, y) {
      MonotoneX.prototype.point.call(this, y, x);
    };
  
    function ReflectContext(context) {
      this._context = context;
    }
  
    ReflectContext.prototype = {
      moveTo: function(x, y) { this._context.moveTo(y, x); },
      closePath: function() { this._context.closePath(); },
      lineTo: function(x, y) { this._context.lineTo(y, x); },
      bezierCurveTo: function(x1, y1, x2, y2, x, y) { this._context.bezierCurveTo(y1, x1, y2, x2, y, x); }
    };
  
    function monotoneX(context) {
      return new MonotoneX(context);
    }
  
    function monotoneY(context) {
      return new MonotoneY(context);
    }
  
    function Natural(context) {
      this._context = context;
    }
  
    Natural.prototype = {
      areaStart: function() {
        this._line = 0;
      },
      areaEnd: function() {
        this._line = NaN;
      },
      lineStart: function() {
        this._x = [];
        this._y = [];
      },
      lineEnd: function() {
        var x = this._x,
            y = this._y,
            n = x.length;
  
        if (n) {
          this._line ? this._context.lineTo(x[0], y[0]) : this._context.moveTo(x[0], y[0]);
          if (n === 2) {
            this._context.lineTo(x[1], y[1]);
          } else {
            var px = controlPoints(x),
                py = controlPoints(y);
            for (var i0 = 0, i1 = 1; i1 < n; ++i0, ++i1) {
              this._context.bezierCurveTo(px[0][i0], py[0][i0], px[1][i0], py[1][i0], x[i1], y[i1]);
            }
          }
        }
  
        if (this._line || (this._line !== 0 && n === 1)) this._context.closePath();
        this._line = 1 - this._line;
        this._x = this._y = null;
      },
      point: function(x, y) {
        this._x.push(+x);
        this._y.push(+y);
      }
    };
  
    // See https://www.particleincell.com/2012/bezier-splines/ for derivation.
    function controlPoints(x) {
      var i,
          n = x.length - 1,
          m,
          a = new Array(n),
          b = new Array(n),
          r = new Array(n);
      a[0] = 0, b[0] = 2, r[0] = x[0] + 2 * x[1];
      for (i = 1; i < n - 1; ++i) a[i] = 1, b[i] = 4, r[i] = 4 * x[i] + 2 * x[i + 1];
      a[n - 1] = 2, b[n - 1] = 7, r[n - 1] = 8 * x[n - 1] + x[n];
      for (i = 1; i < n; ++i) m = a[i] / b[i - 1], b[i] -= m, r[i] -= m * r[i - 1];
      a[n - 1] = r[n - 1] / b[n - 1];
      for (i = n - 2; i >= 0; --i) a[i] = (r[i] - a[i + 1]) / b[i];
      b[n - 1] = (x[n] + a[n - 1]) / 2;
      for (i = 0; i < n - 1; ++i) b[i] = 2 * x[i + 1] - a[i + 1];
      return [a, b];
    }
  
    function natural(context) {
      return new Natural(context);
    }
  
    function Step(context, t) {
      this._context = context;
      this._t = t;
    }
  
    Step.prototype = {
      areaStart: function() {
        this._line = 0;
      },
      areaEnd: function() {
        this._line = NaN;
      },
      lineStart: function() {
        this._x = this._y = NaN;
        this._point = 0;
      },
      lineEnd: function() {
        if (0 < this._t && this._t < 1 && this._point === 2) this._context.lineTo(this._x, this._y);
        if (this._line || (this._line !== 0 && this._point === 1)) this._context.closePath();
        if (this._line >= 0) this._t = 1 - this._t, this._line = 1 - this._line;
      },
      point: function(x, y) {
        x = +x, y = +y;
        switch (this._point) {
          case 0: this._point = 1; this._line ? this._context.lineTo(x, y) : this._context.moveTo(x, y); break;
          case 1: this._point = 2; // proceed
          default: {
            if (this._t <= 0) {
              this._context.lineTo(this._x, y);
              this._context.lineTo(x, y);
            } else {
              var x1 = this._x * (1 - this._t) + x * this._t;
              this._context.lineTo(x1, this._y);
              this._context.lineTo(x1, y);
            }
            break;
          }
        }
        this._x = x, this._y = y;
      }
    };
  
    function step(context) {
      return new Step(context, 0.5);
    }
  
    function stepBefore(context) {
      return new Step(context, 0);
    }
  
    function stepAfter(context) {
      return new Step(context, 1);
    }
  
    var slice$2 = Array.prototype.slice;
  
    function none(series, order) {
      if (!((n = series.length) > 1)) return;
      for (var i = 1, s0, s1 = series[order[0]], n, m = s1.length; i < n; ++i) {
        s0 = s1, s1 = series[order[i]];
        for (var j = 0; j < m; ++j) {
          s1[j][1] += s1[j][0] = isNaN(s0[j][1]) ? s0[j][0] : s0[j][1];
        }
      }
    }
  
    function none$1(series) {
      var n = series.length, o = new Array(n);
      while (--n >= 0) o[n] = n;
      return o;
    }
  
    function stackValue(d, key) {
      return d[key];
    }
  
    function stack() {
      var keys = constant$1([]),
          order = none$1,
          offset = none,
          value = stackValue;
  
      function stack(data) {
        var kz = keys.apply(this, arguments),
            i,
            m = data.length,
            n = kz.length,
            sz = new Array(n),
            oz;
  
        for (i = 0; i < n; ++i) {
          for (var ki = kz[i], si = sz[i] = new Array(m), j = 0, sij; j < m; ++j) {
            si[j] = sij = [0, +value(data[j], ki, j, data)];
            sij.data = data[j];
          }
          si.key = ki;
        }
  
        for (i = 0, oz = order(sz); i < n; ++i) {
          sz[oz[i]].index = i;
        }
  
        offset(sz, oz);
        return sz;
      }
  
      stack.keys = function(_) {
        return arguments.length ? (keys = typeof _ === "function" ? _ : constant$1(slice$2.call(_)), stack) : keys;
      };
  
      stack.value = function(_) {
        return arguments.length ? (value = typeof _ === "function" ? _ : constant$1(+_), stack) : value;
      };
  
      stack.order = function(_) {
        return arguments.length ? (order = _ == null ? none$1 : typeof _ === "function" ? _ : constant$1(slice$2.call(_)), stack) : order;
      };
  
      stack.offset = function(_) {
        return arguments.length ? (offset = _ == null ? none : _, stack) : offset;
      };
  
      return stack;
    }
  
    function expand(series, order) {
      if (!((n = series.length) > 0)) return;
      for (var i, n, j = 0, m = series[0].length, y; j < m; ++j) {
        for (y = i = 0; i < n; ++i) y += series[i][j][1] || 0;
        if (y) for (i = 0; i < n; ++i) series[i][j][1] /= y;
      }
      none(series, order);
    }
  
    function silhouette(series, order) {
      if (!((n = series.length) > 0)) return;
      for (var j = 0, s0 = series[order[0]], n, m = s0.length; j < m; ++j) {
        for (var i = 0, y = 0; i < n; ++i) y += series[i][j][1] || 0;
        s0[j][1] += s0[j][0] = -y / 2;
      }
      none(series, order);
    }
  
    function wiggle(series, order) {
      if (!((n = series.length) > 0) || !((m = (s0 = series[order[0]]).length) > 0)) return;
      for (var y = 0, j = 1, s0, m, n; j < m; ++j) {
        for (var i = 0, s1 = 0, s2 = 0; i < n; ++i) {
          var si = series[order[i]],
              sij0 = si[j][1] || 0,
              sij1 = si[j - 1][1] || 0,
              s3 = (sij0 - sij1) / 2;
          for (var k = 0; k < i; ++k) {
            var sk = series[order[k]],
                skj0 = sk[j][1] || 0,
                skj1 = sk[j - 1][1] || 0;
            s3 += skj0 - skj1;
          }
          s1 += sij0, s2 += s3 * sij0;
        }
        s0[j - 1][1] += s0[j - 1][0] = y;
        if (s1) y -= s2 / s1;
      }
      s0[j - 1][1] += s0[j - 1][0] = y;
      none(series, order);
    }
  
    function ascending$1(series) {
      var sums = series.map(sum$1);
      return none$1(series).sort(function(a, b) { return sums[a] - sums[b]; });
    }
  
    function sum$1(series) {
      var s = 0, i = -1, n = series.length, v;
      while (++i < n) if (v = +series[i][1]) s += v;
      return s;
    }
  
    function descending$2(series) {
      return ascending$1(series).reverse();
    }
  
    function insideOut(series) {
      var n = series.length,
          i,
          j,
          sums = series.map(sum$1),
          order = none$1(series).sort(function(a, b) { return sums[b] - sums[a]; }),
          top = 0,
          bottom = 0,
          tops = [],
          bottoms = [];
  
      for (i = 0; i < n; ++i) {
        j = order[i];
        if (top < bottom) {
          top += sums[j];
          tops.push(j);
        } else {
          bottom += sums[j];
          bottoms.push(j);
        }
      }
  
      return bottoms.reverse().concat(tops);
    }
  
    function reverse(series) {
      return none$1(series).reverse();
    }
  
    function define(constructor, factory, prototype) {
      constructor.prototype = factory.prototype = prototype;
      prototype.constructor = constructor;
    }
  
    function extend(parent, definition) {
      var prototype = Object.create(parent.prototype);
      for (var key in definition) prototype[key] = definition[key];
      return prototype;
    }
  
    function Color() {}
  
    var darker = 0.7;
    var brighter = 1 / darker;
  
    var reHex3 = /^#([0-9a-f]{3})$/;
    var reHex6 = /^#([0-9a-f]{6})$/;
    var reRgbInteger = /^rgb\(\s*([-+]?\d+)\s*,\s*([-+]?\d+)\s*,\s*([-+]?\d+)\s*\)$/;
    var reRgbPercent = /^rgb\(\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*\)$/;
    var reRgbaInteger = /^rgba\(\s*([-+]?\d+)\s*,\s*([-+]?\d+)\s*,\s*([-+]?\d+)\s*,\s*([-+]?\d+(?:\.\d+)?)\s*\)$/;
    var reRgbaPercent = /^rgba\(\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)\s*\)$/;
    var reHslPercent = /^hsl\(\s*([-+]?\d+(?:\.\d+)?)\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*\)$/;
    var reHslaPercent = /^hsla\(\s*([-+]?\d+(?:\.\d+)?)\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)%\s*,\s*([-+]?\d+(?:\.\d+)?)\s*\)$/;
    var named = {
      aliceblue: 0xf0f8ff,
      antiquewhite: 0xfaebd7,
      aqua: 0x00ffff,
      aquamarine: 0x7fffd4,
      azure: 0xf0ffff,
      beige: 0xf5f5dc,
      bisque: 0xffe4c4,
      black: 0x000000,
      blanchedalmond: 0xffebcd,
      blue: 0x0000ff,
      blueviolet: 0x8a2be2,
      brown: 0xa52a2a,
      burlywood: 0xdeb887,
      cadetblue: 0x5f9ea0,
      chartreuse: 0x7fff00,
      chocolate: 0xd2691e,
      coral: 0xff7f50,
      cornflowerblue: 0x6495ed,
      cornsilk: 0xfff8dc,
      crimson: 0xdc143c,
      cyan: 0x00ffff,
      darkblue: 0x00008b,
      darkcyan: 0x008b8b,
      darkgoldenrod: 0xb8860b,
      darkgray: 0xa9a9a9,
      darkgreen: 0x006400,
      darkgrey: 0xa9a9a9,
      darkkhaki: 0xbdb76b,
      darkmagenta: 0x8b008b,
      darkolivegreen: 0x556b2f,
      darkorange: 0xff8c00,
      darkorchid: 0x9932cc,
      darkred: 0x8b0000,
      darksalmon: 0xe9967a,
      darkseagreen: 0x8fbc8f,
      darkslateblue: 0x483d8b,
      darkslategray: 0x2f4f4f,
      darkslategrey: 0x2f4f4f,
      darkturquoise: 0x00ced1,
      darkviolet: 0x9400d3,
      deeppink: 0xff1493,
      deepskyblue: 0x00bfff,
      dimgray: 0x696969,
      dimgrey: 0x696969,
      dodgerblue: 0x1e90ff,
      firebrick: 0xb22222,
      floralwhite: 0xfffaf0,
      forestgreen: 0x228b22,
      fuchsia: 0xff00ff,
      gainsboro: 0xdcdcdc,
      ghostwhite: 0xf8f8ff,
      gold: 0xffd700,
      goldenrod: 0xdaa520,
      gray: 0x808080,
      green: 0x008000,
      greenyellow: 0xadff2f,
      grey: 0x808080,
      honeydew: 0xf0fff0,
      hotpink: 0xff69b4,
      indianred: 0xcd5c5c,
      indigo: 0x4b0082,
      ivory: 0xfffff0,
      khaki: 0xf0e68c,
      lavender: 0xe6e6fa,
      lavenderblush: 0xfff0f5,
      lawngreen: 0x7cfc00,
      lemonchiffon: 0xfffacd,
      lightblue: 0xadd8e6,
      lightcoral: 0xf08080,
      lightcyan: 0xe0ffff,
      lightgoldenrodyellow: 0xfafad2,
      lightgray: 0xd3d3d3,
      lightgreen: 0x90ee90,
      lightgrey: 0xd3d3d3,
      lightpink: 0xffb6c1,
      lightsalmon: 0xffa07a,
      lightseagreen: 0x20b2aa,
      lightskyblue: 0x87cefa,
      lightslategray: 0x778899,
      lightslategrey: 0x778899,
      lightsteelblue: 0xb0c4de,
      lightyellow: 0xffffe0,
      lime: 0x00ff00,
      limegreen: 0x32cd32,
      linen: 0xfaf0e6,
      magenta: 0xff00ff,
      maroon: 0x800000,
      mediumaquamarine: 0x66cdaa,
      mediumblue: 0x0000cd,
      mediumorchid: 0xba55d3,
      mediumpurple: 0x9370db,
      mediumseagreen: 0x3cb371,
      mediumslateblue: 0x7b68ee,
      mediumspringgreen: 0x00fa9a,
      mediumturquoise: 0x48d1cc,
      mediumvioletred: 0xc71585,
      midnightblue: 0x191970,
      mintcream: 0xf5fffa,
      mistyrose: 0xffe4e1,
      moccasin: 0xffe4b5,
      navajowhite: 0xffdead,
      navy: 0x000080,
      oldlace: 0xfdf5e6,
      olive: 0x808000,
      olivedrab: 0x6b8e23,
      orange: 0xffa500,
      orangered: 0xff4500,
      orchid: 0xda70d6,
      palegoldenrod: 0xeee8aa,
      palegreen: 0x98fb98,
      paleturquoise: 0xafeeee,
      palevioletred: 0xdb7093,
      papayawhip: 0xffefd5,
      peachpuff: 0xffdab9,
      peru: 0xcd853f,
      pink: 0xffc0cb,
      plum: 0xdda0dd,
      powderblue: 0xb0e0e6,
      purple: 0x800080,
      rebeccapurple: 0x663399,
      red: 0xff0000,
      rosybrown: 0xbc8f8f,
      royalblue: 0x4169e1,
      saddlebrown: 0x8b4513,
      salmon: 0xfa8072,
      sandybrown: 0xf4a460,
      seagreen: 0x2e8b57,
      seashell: 0xfff5ee,
      sienna: 0xa0522d,
      silver: 0xc0c0c0,
      skyblue: 0x87ceeb,
      slateblue: 0x6a5acd,
      slategray: 0x708090,
      slategrey: 0x708090,
      snow: 0xfffafa,
      springgreen: 0x00ff7f,
      steelblue: 0x4682b4,
      tan: 0xd2b48c,
      teal: 0x008080,
      thistle: 0xd8bfd8,
      tomato: 0xff6347,
      turquoise: 0x40e0d0,
      violet: 0xee82ee,
      wheat: 0xf5deb3,
      white: 0xffffff,
      whitesmoke: 0xf5f5f5,
      yellow: 0xffff00,
      yellowgreen: 0x9acd32
    };
  
    define(Color, color, {
      displayable: function() {
        return this.rgb().displayable();
      },
      toString: function() {
        return this.rgb() + "";
      }
    });
  
    function color(format) {
      var m;
      format = (format + "").trim().toLowerCase();
      return (m = reHex3.exec(format)) ? (m = parseInt(m[1], 16), new Rgb((m >> 8 & 0xf) | (m >> 4 & 0x0f0), (m >> 4 & 0xf) | (m & 0xf0), ((m & 0xf) << 4) | (m & 0xf), 1)) // #f00
          : (m = reHex6.exec(format)) ? rgbn(parseInt(m[1], 16)) // #ff0000
          : (m = reRgbInteger.exec(format)) ? new Rgb(m[1], m[2], m[3], 1) // rgb(255, 0, 0)
          : (m = reRgbPercent.exec(format)) ? new Rgb(m[1] * 255 / 100, m[2] * 255 / 100, m[3] * 255 / 100, 1) // rgb(100%, 0%, 0%)
          : (m = reRgbaInteger.exec(format)) ? rgba(m[1], m[2], m[3], m[4]) // rgba(255, 0, 0, 1)
          : (m = reRgbaPercent.exec(format)) ? rgba(m[1] * 255 / 100, m[2] * 255 / 100, m[3] * 255 / 100, m[4]) // rgb(100%, 0%, 0%, 1)
          : (m = reHslPercent.exec(format)) ? hsla(m[1], m[2] / 100, m[3] / 100, 1) // hsl(120, 50%, 50%)
          : (m = reHslaPercent.exec(format)) ? hsla(m[1], m[2] / 100, m[3] / 100, m[4]) // hsla(120, 50%, 50%, 1)
          : named.hasOwnProperty(format) ? rgbn(named[format])
          : format === "transparent" ? new Rgb(NaN, NaN, NaN, 0)
          : null;
    }
  
    function rgbn(n) {
      return new Rgb(n >> 16 & 0xff, n >> 8 & 0xff, n & 0xff, 1);
    }
  
    function rgba(r, g, b, a) {
      if (a <= 0) r = g = b = NaN;
      return new Rgb(r, g, b, a);
    }
  
    function rgbConvert(o) {
      if (!(o instanceof Color)) o = color(o);
      if (!o) return new Rgb;
      o = o.rgb();
      return new Rgb(o.r, o.g, o.b, o.opacity);
    }
  
    function colorRgb(r, g, b, opacity) {
      return arguments.length === 1 ? rgbConvert(r) : new Rgb(r, g, b, opacity == null ? 1 : opacity);
    }
  
    function Rgb(r, g, b, opacity) {
      this.r = +r;
      this.g = +g;
      this.b = +b;
      this.opacity = +opacity;
    }
  
    define(Rgb, colorRgb, extend(Color, {
      brighter: function(k) {
        k = k == null ? brighter : Math.pow(brighter, k);
        return new Rgb(this.r * k, this.g * k, this.b * k, this.opacity);
      },
      darker: function(k) {
        k = k == null ? darker : Math.pow(darker, k);
        return new Rgb(this.r * k, this.g * k, this.b * k, this.opacity);
      },
      rgb: function() {
        return this;
      },
      displayable: function() {
        return (0 <= this.r && this.r <= 255)
            && (0 <= this.g && this.g <= 255)
            && (0 <= this.b && this.b <= 255)
            && (0 <= this.opacity && this.opacity <= 1);
      },
      toString: function() {
        var a = this.opacity; a = isNaN(a) ? 1 : Math.max(0, Math.min(1, a));
        return (a === 1 ? "rgb(" : "rgba(")
            + Math.max(0, Math.min(255, Math.round(this.r) || 0)) + ", "
            + Math.max(0, Math.min(255, Math.round(this.g) || 0)) + ", "
            + Math.max(0, Math.min(255, Math.round(this.b) || 0))
            + (a === 1 ? ")" : ", " + a + ")");
      }
    }));
  
    function hsla(h, s, l, a) {
      if (a <= 0) h = s = l = NaN;
      else if (l <= 0 || l >= 1) h = s = NaN;
      else if (s <= 0) h = NaN;
      return new Hsl(h, s, l, a);
    }
  
    function hslConvert(o) {
      if (o instanceof Hsl) return new Hsl(o.h, o.s, o.l, o.opacity);
      if (!(o instanceof Color)) o = color(o);
      if (!o) return new Hsl;
      if (o instanceof Hsl) return o;
      o = o.rgb();
      var r = o.r / 255,
          g = o.g / 255,
          b = o.b / 255,
          min = Math.min(r, g, b),
          max = Math.max(r, g, b),
          h = NaN,
          s = max - min,
          l = (max + min) / 2;
      if (s) {
        if (r === max) h = (g - b) / s + (g < b) * 6;
        else if (g === max) h = (b - r) / s + 2;
        else h = (r - g) / s + 4;
        s /= l < 0.5 ? max + min : 2 - max - min;
        h *= 60;
      } else {
        s = l > 0 && l < 1 ? 0 : h;
      }
      return new Hsl(h, s, l, o.opacity);
    }
  
    function colorHsl(h, s, l, opacity) {
      return arguments.length === 1 ? hslConvert(h) : new Hsl(h, s, l, opacity == null ? 1 : opacity);
    }
  
    function Hsl(h, s, l, opacity) {
      this.h = +h;
      this.s = +s;
      this.l = +l;
      this.opacity = +opacity;
    }
  
    define(Hsl, colorHsl, extend(Color, {
      brighter: function(k) {
        k = k == null ? brighter : Math.pow(brighter, k);
        return new Hsl(this.h, this.s, this.l * k, this.opacity);
      },
      darker: function(k) {
        k = k == null ? darker : Math.pow(darker, k);
        return new Hsl(this.h, this.s, this.l * k, this.opacity);
      },
      rgb: function() {
        var h = this.h % 360 + (this.h < 0) * 360,
            s = isNaN(h) || isNaN(this.s) ? 0 : this.s,
            l = this.l,
            m2 = l + (l < 0.5 ? l : 1 - l) * s,
            m1 = 2 * l - m2;
        return new Rgb(
          hsl2rgb(h >= 240 ? h - 240 : h + 120, m1, m2),
          hsl2rgb(h, m1, m2),
          hsl2rgb(h < 120 ? h + 240 : h - 120, m1, m2),
          this.opacity
        );
      },
      displayable: function() {
        return (0 <= this.s && this.s <= 1 || isNaN(this.s))
            && (0 <= this.l && this.l <= 1)
            && (0 <= this.opacity && this.opacity <= 1);
      }
    }));
  
    /* From FvD 13.37, CSS Color Module Level 3 */
    function hsl2rgb(h, m1, m2) {
      return (h < 60 ? m1 + (m2 - m1) * h / 60
          : h < 180 ? m2
          : h < 240 ? m1 + (m2 - m1) * (240 - h) / 60
          : m1) * 255;
    }
  
    var deg2rad = Math.PI / 180;
    var rad2deg = 180 / Math.PI;
  
    var Kn = 18;
    var Xn = 0.950470;
    var Yn = 1;
    var Zn = 1.088830;
    var t0 = 4 / 29;
    var t1 = 6 / 29;
    var t2 = 3 * t1 * t1;
    var t3 = t1 * t1 * t1;
    function labConvert(o) {
      if (o instanceof Lab) return new Lab(o.l, o.a, o.b, o.opacity);
      if (o instanceof Hcl) {
        var h = o.h * deg2rad;
        return new Lab(o.l, Math.cos(h) * o.c, Math.sin(h) * o.c, o.opacity);
      }
      if (!(o instanceof Rgb)) o = rgbConvert(o);
      var b = rgb2xyz(o.r),
          a = rgb2xyz(o.g),
          l = rgb2xyz(o.b),
          x = xyz2lab((0.4124564 * b + 0.3575761 * a + 0.1804375 * l) / Xn),
          y = xyz2lab((0.2126729 * b + 0.7151522 * a + 0.0721750 * l) / Yn),
          z = xyz2lab((0.0193339 * b + 0.1191920 * a + 0.9503041 * l) / Zn);
      return new Lab(116 * y - 16, 500 * (x - y), 200 * (y - z), o.opacity);
    }
  
    function lab(l, a, b, opacity) {
      return arguments.length === 1 ? labConvert(l) : new Lab(l, a, b, opacity == null ? 1 : opacity);
    }
  
    function Lab(l, a, b, opacity) {
      this.l = +l;
      this.a = +a;
      this.b = +b;
      this.opacity = +opacity;
    }
  
    define(Lab, lab, extend(Color, {
      brighter: function(k) {
        return new Lab(this.l + Kn * (k == null ? 1 : k), this.a, this.b, this.opacity);
      },
      darker: function(k) {
        return new Lab(this.l - Kn * (k == null ? 1 : k), this.a, this.b, this.opacity);
      },
      rgb: function() {
        var y = (this.l + 16) / 116,
            x = isNaN(this.a) ? y : y + this.a / 500,
            z = isNaN(this.b) ? y : y - this.b / 200;
        y = Yn * lab2xyz(y);
        x = Xn * lab2xyz(x);
        z = Zn * lab2xyz(z);
        return new Rgb(
          xyz2rgb( 3.2404542 * x - 1.5371385 * y - 0.4985314 * z), // D65 -> sRGB
          xyz2rgb(-0.9692660 * x + 1.8760108 * y + 0.0415560 * z),
          xyz2rgb( 0.0556434 * x - 0.2040259 * y + 1.0572252 * z),
          this.opacity
        );
      }
    }));
  
    function xyz2lab(t) {
      return t > t3 ? Math.pow(t, 1 / 3) : t / t2 + t0;
    }
  
    function lab2xyz(t) {
      return t > t1 ? t * t * t : t2 * (t - t0);
    }
  
    function xyz2rgb(x) {
      return 255 * (x <= 0.0031308 ? 12.92 * x : 1.055 * Math.pow(x, 1 / 2.4) - 0.055);
    }
  
    function rgb2xyz(x) {
      return (x /= 255) <= 0.04045 ? x / 12.92 : Math.pow((x + 0.055) / 1.055, 2.4);
    }
  
    function hclConvert(o) {
      if (o instanceof Hcl) return new Hcl(o.h, o.c, o.l, o.opacity);
      if (!(o instanceof Lab)) o = labConvert(o);
      var h = Math.atan2(o.b, o.a) * rad2deg;
      return new Hcl(h < 0 ? h + 360 : h, Math.sqrt(o.a * o.a + o.b * o.b), o.l, o.opacity);
    }
  
    function colorHcl(h, c, l, opacity) {
      return arguments.length === 1 ? hclConvert(h) : new Hcl(h, c, l, opacity == null ? 1 : opacity);
    }
  
    function Hcl(h, c, l, opacity) {
      this.h = +h;
      this.c = +c;
      this.l = +l;
      this.opacity = +opacity;
    }
  
    define(Hcl, colorHcl, extend(Color, {
      brighter: function(k) {
        return new Hcl(this.h, this.c, this.l + Kn * (k == null ? 1 : k), this.opacity);
      },
      darker: function(k) {
        return new Hcl(this.h, this.c, this.l - Kn * (k == null ? 1 : k), this.opacity);
      },
      rgb: function() {
        return labConvert(this).rgb();
      }
    }));
  
    var A = -0.14861;
    var B = +1.78277;
    var C = -0.29227;
    var D = -0.90649;
    var E = +1.97294;
    var ED = E * D;
    var EB = E * B;
    var BC_DA = B * C - D * A;
    function cubehelixConvert(o) {
      if (o instanceof Cubehelix) return new Cubehelix(o.h, o.s, o.l, o.opacity);
      if (!(o instanceof Rgb)) o = rgbConvert(o);
      var r = o.r / 255,
          g = o.g / 255,
          b = o.b / 255,
          l = (BC_DA * b + ED * r - EB * g) / (BC_DA + ED - EB),
          bl = b - l,
          k = (E * (g - l) - C * bl) / D,
          s = Math.sqrt(k * k + bl * bl) / (E * l * (1 - l)), // NaN if l=0 or l=1
          h = s ? Math.atan2(k, bl) * rad2deg - 120 : NaN;
      return new Cubehelix(h < 0 ? h + 360 : h, s, l, o.opacity);
    }
  
    function cubehelix(h, s, l, opacity) {
      return arguments.length === 1 ? cubehelixConvert(h) : new Cubehelix(h, s, l, opacity == null ? 1 : opacity);
    }
  
    function Cubehelix(h, s, l, opacity) {
      this.h = +h;
      this.s = +s;
      this.l = +l;
      this.opacity = +opacity;
    }
  
    define(Cubehelix, cubehelix, extend(Color, {
      brighter: function(k) {
        k = k == null ? brighter : Math.pow(brighter, k);
        return new Cubehelix(this.h, this.s, this.l * k, this.opacity);
      },
      darker: function(k) {
        k = k == null ? darker : Math.pow(darker, k);
        return new Cubehelix(this.h, this.s, this.l * k, this.opacity);
      },
      rgb: function() {
        var h = isNaN(this.h) ? 0 : (this.h + 120) * deg2rad,
            l = +this.l,
            a = isNaN(this.s) ? 0 : this.s * l * (1 - l),
            cosh = Math.cos(h),
            sinh = Math.sin(h);
        return new Rgb(
          255 * (l + a * (A * cosh + B * sinh)),
          255 * (l + a * (C * cosh + D * sinh)),
          255 * (l + a * (E * cosh)),
          this.opacity
        );
      }
    }));
  
    function basis$1(t1, v0, v1, v2, v3) {
      var t2 = t1 * t1, t3 = t2 * t1;
      return ((1 - 3 * t1 + 3 * t2 - t3) * v0
          + (4 - 6 * t2 + 3 * t3) * v1
          + (1 + 3 * t1 + 3 * t2 - 3 * t3) * v2
          + t3 * v3) / 6;
    }
  
    function basis$2(values) {
      var n = values.length - 1;
      return function(t) {
        var i = t <= 0 ? (t = 0) : t >= 1 ? (t = 1, n - 1) : Math.floor(t * n),
            v1 = values[i],
            v2 = values[i + 1],
            v0 = i > 0 ? values[i - 1] : 2 * v1 - v2,
            v3 = i < n - 1 ? values[i + 2] : 2 * v2 - v1;
        return basis$1((t - i / n) * n, v0, v1, v2, v3);
      };
    }
  
    function basisClosed$1(values) {
      var n = values.length;
      return function(t) {
        var i = Math.floor(((t %= 1) < 0 ? ++t : t) * n),
            v0 = values[(i + n - 1) % n],
            v1 = values[i % n],
            v2 = values[(i + 1) % n],
            v3 = values[(i + 2) % n];
        return basis$1((t - i / n) * n, v0, v1, v2, v3);
      };
    }
  
    function constant$2(x) {
      return function() {
        return x;
      };
    }
  
    function linear$1(a, d) {
      return function(t) {
        return a + t * d;
      };
    }
  
    function exponential$1(a, b, y) {
      return a = Math.pow(a, y), b = Math.pow(b, y) - a, y = 1 / y, function(t) {
        return Math.pow(a + t * b, y);
      };
    }
  
    function hue(a, b) {
      var d = b - a;
      return d ? linear$1(a, d > 180 || d < -180 ? d - 360 * Math.round(d / 360) : d) : constant$2(isNaN(a) ? b : a);
    }
  
    function gamma(y) {
      return (y = +y) === 1 ? nogamma : function(a, b) {
        return b - a ? exponential$1(a, b, y) : constant$2(isNaN(a) ? b : a);
      };
    }
  
    function nogamma(a, b) {
      var d = b - a;
      return d ? linear$1(a, d) : constant$2(isNaN(a) ? b : a);
    }
  
    var interpolateRgb = (function rgbGamma(y) {
      var color = gamma(y);
  
      function rgb(start, end) {
        var r = color((start = colorRgb(start)).r, (end = colorRgb(end)).r),
            g = color(start.g, end.g),
            b = color(start.b, end.b),
            opacity = color(start.opacity, end.opacity);
        return function(t) {
          start.r = r(t);
          start.g = g(t);
          start.b = b(t);
          start.opacity = opacity(t);
          return start + "";
        };
      }
  
      rgb.gamma = rgbGamma;
  
      return rgb;
    })(1);
  
    function rgbSpline(spline) {
      return function(colors) {
        var n = colors.length,
            r = new Array(n),
            g = new Array(n),
            b = new Array(n),
            i, color;
        for (i = 0; i < n; ++i) {
          color = colorRgb(colors[i]);
          r[i] = color.r || 0;
          g[i] = color.g || 0;
          b[i] = color.b || 0;
        }
        r = spline(r);
        g = spline(g);
        b = spline(b);
        color.opacity = 1;
        return function(t) {
          color.r = r(t);
          color.g = g(t);
          color.b = b(t);
          return color + "";
        };
      };
    }
  
    var rgbBasis = rgbSpline(basis$2);
    var rgbBasisClosed = rgbSpline(basisClosed$1);
  
    function array$1(a, b) {
      var nb = b ? b.length : 0,
          na = a ? Math.min(nb, a.length) : 0,
          x = new Array(nb),
          c = new Array(nb),
          i;
  
      for (i = 0; i < na; ++i) x[i] = interpolate(a[i], b[i]);
      for (; i < nb; ++i) c[i] = b[i];
  
      return function(t) {
        for (i = 0; i < na; ++i) c[i] = x[i](t);
        return c;
      };
    }
  
    function date(a, b) {
      var d = new Date;
      return a = +a, b -= a, function(t) {
        return d.setTime(a + b * t), d;
      };
    }
  
    function interpolateNumber(a, b) {
      return a = +a, b -= a, function(t) {
        return a + b * t;
      };
    }
  
    function object(a, b) {
      var i = {},
          c = {},
          k;
  
      if (a === null || typeof a !== "object") a = {};
      if (b === null || typeof b !== "object") b = {};
  
      for (k in b) {
        if (k in a) {
          i[k] = interpolate(a[k], b[k]);
        } else {
          c[k] = b[k];
        }
      }
  
      return function(t) {
        for (k in i) c[k] = i[k](t);
        return c;
      };
    }
  
    var reA = /[-+]?(?:\d+\.?\d*|\.?\d+)(?:[eE][-+]?\d+)?/g;
    var reB = new RegExp(reA.source, "g");
    function zero(b) {
      return function() {
        return b;
      };
    }
  
    function one(b) {
      return function(t) {
        return b(t) + "";
      };
    }
  
    function interpolateString(a, b) {
      var bi = reA.lastIndex = reB.lastIndex = 0, // scan index for next number in b
          am, // current match in a
          bm, // current match in b
          bs, // string preceding current number in b, if any
          i = -1, // index in s
          s = [], // string constants and placeholders
          q = []; // number interpolators
  
      // Coerce inputs to strings.
      a = a + "", b = b + "";
  
      // Interpolate pairs of numbers in a & b.
      while ((am = reA.exec(a))
          && (bm = reB.exec(b))) {
        if ((bs = bm.index) > bi) { // a string precedes the next number in b
          bs = b.slice(bi, bs);
          if (s[i]) s[i] += bs; // coalesce with previous string
          else s[++i] = bs;
        }
        if ((am = am[0]) === (bm = bm[0])) { // numbers in a & b match
          if (s[i]) s[i] += bm; // coalesce with previous string
          else s[++i] = bm;
        } else { // interpolate non-matching numbers
          s[++i] = null;
          q.push({i: i, x: interpolateNumber(am, bm)});
        }
        bi = reB.lastIndex;
      }
  
      // Add remains of b.
      if (bi < b.length) {
        bs = b.slice(bi);
        if (s[i]) s[i] += bs; // coalesce with previous string
        else s[++i] = bs;
      }
  
      // Special optimization for only a single match.
      // Otherwise, interpolate each of the numbers and rejoin the string.
      return s.length < 2 ? (q[0]
          ? one(q[0].x)
          : zero(b))
          : (b = q.length, function(t) {
              for (var i = 0, o; i < b; ++i) s[(o = q[i]).i] = o.x(t);
              return s.join("");
            });
    }
  
    function interpolate(a, b) {
      var t = typeof b, c;
      return b == null || t === "boolean" ? constant$2(b)
          : (t === "number" ? interpolateNumber
          : t === "string" ? ((c = color(b)) ? (b = c, interpolateRgb) : interpolateString)
          : b instanceof color ? interpolateRgb
          : b instanceof Date ? date
          : Array.isArray(b) ? array$1
          : isNaN(b) ? object
          : interpolateNumber)(a, b);
    }
  
    function interpolateRound(a, b) {
      return a = +a, b -= a, function(t) {
        return Math.round(a + b * t);
      };
    }
  
    var degrees = 180 / Math.PI;
  
    var identity$2 = {
      translateX: 0,
      translateY: 0,
      rotate: 0,
      skewX: 0,
      scaleX: 1,
      scaleY: 1
    };
  
    function decompose(a, b, c, d, e, f) {
      var scaleX, scaleY, skewX;
      if (scaleX = Math.sqrt(a * a + b * b)) a /= scaleX, b /= scaleX;
      if (skewX = a * c + b * d) c -= a * skewX, d -= b * skewX;
      if (scaleY = Math.sqrt(c * c + d * d)) c /= scaleY, d /= scaleY, skewX /= scaleY;
      if (a * d < b * c) a = -a, b = -b, skewX = -skewX, scaleX = -scaleX;
      return {
        translateX: e,
        translateY: f,
        rotate: Math.atan2(b, a) * degrees,
        skewX: Math.atan(skewX) * degrees,
        scaleX: scaleX,
        scaleY: scaleY
      };
    }
  
    var cssNode;
    var cssRoot;
    var cssView;
    var svgNode;
    function parseCss(value) {
      if (value === "none") return identity$2;
      if (!cssNode) cssNode = document.createElement("DIV"), cssRoot = document.documentElement, cssView = document.defaultView;
      cssNode.style.transform = value;
      value = cssView.getComputedStyle(cssRoot.appendChild(cssNode), null).getPropertyValue("transform");
      cssRoot.removeChild(cssNode);
      value = value.slice(7, -1).split(",");
      return decompose(+value[0], +value[1], +value[2], +value[3], +value[4], +value[5]);
    }
  
    function parseSvg(value) {
      if (value == null) return identity$2;
      if (!svgNode) svgNode = document.createElementNS("http://www.w3.org/2000/svg", "g");
      svgNode.setAttribute("transform", value);
      if (!(value = svgNode.transform.baseVal.consolidate())) return identity$2;
      value = value.matrix;
      return decompose(value.a, value.b, value.c, value.d, value.e, value.f);
    }
  
    function interpolateTransform(parse, pxComma, pxParen, degParen) {
  
      function pop(s) {
        return s.length ? s.pop() + " " : "";
      }
  
      function translate(xa, ya, xb, yb, s, q) {
        if (xa !== xb || ya !== yb) {
          var i = s.push("translate(", null, pxComma, null, pxParen);
          q.push({i: i - 4, x: interpolateNumber(xa, xb)}, {i: i - 2, x: interpolateNumber(ya, yb)});
        } else if (xb || yb) {
          s.push("translate(" + xb + pxComma + yb + pxParen);
        }
      }
  
      function rotate(a, b, s, q) {
        if (a !== b) {
          if (a - b > 180) b += 360; else if (b - a > 180) a += 360; // shortest path
          q.push({i: s.push(pop(s) + "rotate(", null, degParen) - 2, x: interpolateNumber(a, b)});
        } else if (b) {
          s.push(pop(s) + "rotate(" + b + degParen);
        }
      }
  
      function skewX(a, b, s, q) {
        if (a !== b) {
          q.push({i: s.push(pop(s) + "skewX(", null, degParen) - 2, x: interpolateNumber(a, b)});
        } else if (b) {
          s.push(pop(s) + "skewX(" + b + degParen);
        }
      }
  
      function scale(xa, ya, xb, yb, s, q) {
        if (xa !== xb || ya !== yb) {
          var i = s.push(pop(s) + "scale(", null, ",", null, ")");
          q.push({i: i - 4, x: interpolateNumber(xa, xb)}, {i: i - 2, x: interpolateNumber(ya, yb)});
        } else if (xb !== 1 || yb !== 1) {
          s.push(pop(s) + "scale(" + xb + "," + yb + ")");
        }
      }
  
      return function(a, b) {
        var s = [], // string constants and placeholders
            q = []; // number interpolators
        a = parse(a), b = parse(b);
        translate(a.translateX, a.translateY, b.translateX, b.translateY, s, q);
        rotate(a.rotate, b.rotate, s, q);
        skewX(a.skewX, b.skewX, s, q);
        scale(a.scaleX, a.scaleY, b.scaleX, b.scaleY, s, q);
        a = b = null; // gc
        return function(t) {
          var i = -1, n = q.length, o;
          while (++i < n) s[(o = q[i]).i] = o.x(t);
          return s.join("");
        };
      };
    }
  
    var interpolateTransform$1 = interpolateTransform(parseCss, "px, ", "px)", "deg)");
    var interpolateTransform$2 = interpolateTransform(parseSvg, ", ", ")", ")");
  
    var rho = Math.SQRT2;
    var rho2 = 2;
    var rho4 = 4;
    var epsilon2 = 1e-12;
    function cosh(x) {
      return ((x = Math.exp(x)) + 1 / x) / 2;
    }
  
    function sinh(x) {
      return ((x = Math.exp(x)) - 1 / x) / 2;
    }
  
    function tanh(x) {
      return ((x = Math.exp(2 * x)) - 1) / (x + 1);
    }
  
    // p0 = [ux0, uy0, w0]
    // p1 = [ux1, uy1, w1]
    function interpolateZoom(p0, p1) {
      var ux0 = p0[0], uy0 = p0[1], w0 = p0[2],
          ux1 = p1[0], uy1 = p1[1], w1 = p1[2],
          dx = ux1 - ux0,
          dy = uy1 - uy0,
          d2 = dx * dx + dy * dy,
          i,
          S;
  
      // Special case for u0 ≅ u1.
      if (d2 < epsilon2) {
        S = Math.log(w1 / w0) / rho;
        i = function(t) {
          return [
            ux0 + t * dx,
            uy0 + t * dy,
            w0 * Math.exp(rho * t * S)
          ];
        }
      }
  
      // General case.
      else {
        var d1 = Math.sqrt(d2),
            b0 = (w1 * w1 - w0 * w0 + rho4 * d2) / (2 * w0 * rho2 * d1),
            b1 = (w1 * w1 - w0 * w0 - rho4 * d2) / (2 * w1 * rho2 * d1),
            r0 = Math.log(Math.sqrt(b0 * b0 + 1) - b0),
            r1 = Math.log(Math.sqrt(b1 * b1 + 1) - b1);
        S = (r1 - r0) / rho;
        i = function(t) {
          var s = t * S,
              coshr0 = cosh(r0),
              u = w0 / (rho2 * d1) * (coshr0 * tanh(rho * s + r0) - sinh(r0));
          return [
            ux0 + u * dx,
            uy0 + u * dy,
            w0 * coshr0 / cosh(rho * s + r0)
          ];
        }
      }
  
      i.duration = S * 1000;
  
      return i;
    }
  
    function hsl(hue) {
      return function(start, end) {
        var h = hue((start = colorHsl(start)).h, (end = colorHsl(end)).h),
            s = nogamma(start.s, end.s),
            l = nogamma(start.l, end.l),
            opacity = nogamma(start.opacity, end.opacity);
        return function(t) {
          start.h = h(t);
          start.s = s(t);
          start.l = l(t);
          start.opacity = opacity(t);
          return start + "";
        };
      }
    }
  
    var hsl$1 = hsl(hue);
    var hslLong = hsl(nogamma);
  
    function lab$1(start, end) {
      var l = nogamma((start = lab(start)).l, (end = lab(end)).l),
          a = nogamma(start.a, end.a),
          b = nogamma(start.b, end.b),
          opacity = nogamma(start.opacity, end.opacity);
      return function(t) {
        start.l = l(t);
        start.a = a(t);
        start.b = b(t);
        start.opacity = opacity(t);
        return start + "";
      };
    }
  
    function hcl(hue) {
      return function(start, end) {
        var h = hue((start = colorHcl(start)).h, (end = colorHcl(end)).h),
            c = nogamma(start.c, end.c),
            l = nogamma(start.l, end.l),
            opacity = nogamma(start.opacity, end.opacity);
        return function(t) {
          start.h = h(t);
          start.c = c(t);
          start.l = l(t);
          start.opacity = opacity(t);
          return start + "";
        };
      }
    }
  
    var hcl$1 = hcl(hue);
    var hclLong = hcl(nogamma);
  
    function cubehelix$1(hue) {
      return (function cubehelixGamma(y) {
        y = +y;
  
        function cubehelix$$(start, end) {
          var h = hue((start = cubehelix(start)).h, (end = cubehelix(end)).h),
              s = nogamma(start.s, end.s),
              l = nogamma(start.l, end.l),
              opacity = nogamma(start.opacity, end.opacity);
          return function(t) {
            start.h = h(t);
            start.s = s(t);
            start.l = l(Math.pow(t, y));
            start.opacity = opacity(t);
            return start + "";
          };
        }
  
        cubehelix$$.gamma = cubehelixGamma;
  
        return cubehelix$$;
      })(1);
    }
  
    var cubehelix$2 = cubehelix$1(hue);
    var interpolateCubehelixLong = cubehelix$1(nogamma);
  
    function quantize(interpolator, n) {
      var samples = new Array(n);
      for (var i = 0; i < n; ++i) samples[i] = interpolator(i / (n - 1));
      return samples;
    }
  
    var noop$1 = {value: function() {}};
  
    function dispatch() {
      for (var i = 0, n = arguments.length, _ = {}, t; i < n; ++i) {
        if (!(t = arguments[i] + "") || (t in _)) throw new Error("illegal type: " + t);
        _[t] = [];
      }
      return new Dispatch(_);
    }
  
    function Dispatch(_) {
      this._ = _;
    }
  
    function parseTypenames(typenames, types) {
      return typenames.trim().split(/^|\s+/).map(function(t) {
        var name = "", i = t.indexOf(".");
        if (i >= 0) name = t.slice(i + 1), t = t.slice(0, i);
        if (t && !types.hasOwnProperty(t)) throw new Error("unknown type: " + t);
        return {type: t, name: name};
      });
    }
  
    Dispatch.prototype = dispatch.prototype = {
      constructor: Dispatch,
      on: function(typename, callback) {
        var _ = this._,
            T = parseTypenames(typename + "", _),
            t,
            i = -1,
            n = T.length;
  
        // If no callback was specified, return the callback of the given type and name.
        if (arguments.length < 2) {
          while (++i < n) if ((t = (typename = T[i]).type) && (t = get(_[t], typename.name))) return t;
          return;
        }
  
        // If a type was specified, set the callback for the given type and name.
        // Otherwise, if a null callback was specified, remove callbacks of the given name.
        if (callback != null && typeof callback !== "function") throw new Error("invalid callback: " + callback);
        while (++i < n) {
          if (t = (typename = T[i]).type) _[t] = set$1(_[t], typename.name, callback);
          else if (callback == null) for (t in _) _[t] = set$1(_[t], typename.name, null);
        }
  
        return this;
      },
      copy: function() {
        var copy = {}, _ = this._;
        for (var t in _) copy[t] = _[t].slice();
        return new Dispatch(copy);
      },
      call: function(type, that) {
        if ((n = arguments.length - 2) > 0) for (var args = new Array(n), i = 0, n, t; i < n; ++i) args[i] = arguments[i + 2];
        if (!this._.hasOwnProperty(type)) throw new Error("unknown type: " + type);
        for (t = this._[type], i = 0, n = t.length; i < n; ++i) t[i].value.apply(that, args);
      },
      apply: function(type, that, args) {
        if (!this._.hasOwnProperty(type)) throw new Error("unknown type: " + type);
        for (var t = this._[type], i = 0, n = t.length; i < n; ++i) t[i].value.apply(that, args);
      }
    };
  
    function get(type, name) {
      for (var i = 0, n = type.length, c; i < n; ++i) {
        if ((c = type[i]).name === name) {
          return c.value;
        }
      }
    }
  
    function set$1(type, name, callback) {
      for (var i = 0, n = type.length; i < n; ++i) {
        if (type[i].name === name) {
          type[i] = noop$1, type = type.slice(0, i).concat(type.slice(i + 1));
          break;
        }
      }
      if (callback != null) type.push({name: name, value: callback});
      return type;
    }
  
    function objectConverter(columns) {
      return new Function("d", "return {" + columns.map(function(name, i) {
        return JSON.stringify(name) + ": d[" + i + "]";
      }).join(",") + "}");
    }
  
    function customConverter(columns, f) {
      var object = objectConverter(columns);
      return function(row, i) {
        return f(object(row), i, columns);
      };
    }
  
    // Compute unique columns in order of discovery.
    function inferColumns(rows) {
      var columnSet = Object.create(null),
          columns = [];
  
      rows.forEach(function(row) {
        for (var column in row) {
          if (!(column in columnSet)) {
            columns.push(columnSet[column] = column);
          }
        }
      });
  
      return columns;
    }
  
    function dsv(delimiter) {
      var reFormat = new RegExp("[\"" + delimiter + "\n]"),
          delimiterCode = delimiter.charCodeAt(0);
  
      function parse(text, f) {
        var convert, columns, rows = parseRows(text, function(row, i) {
          if (convert) return convert(row, i - 1);
          columns = row, convert = f ? customConverter(row, f) : objectConverter(row);
        });
        rows.columns = columns;
        return rows;
      }
  
      function parseRows(text, f) {
        var EOL = {}, // sentinel value for end-of-line
            EOF = {}, // sentinel value for end-of-file
            rows = [], // output rows
            N = text.length,
            I = 0, // current character index
            n = 0, // the current line number
            t, // the current token
            eol; // is the current token followed by EOL?
  
        function token() {
          if (I >= N) return EOF; // special case: end of file
          if (eol) return eol = false, EOL; // special case: end of line
  
          // special case: quotes
          var j = I, c;
          if (text.charCodeAt(j) === 34) {
            var i = j;
            while (i++ < N) {
              if (text.charCodeAt(i) === 34) {
                if (text.charCodeAt(i + 1) !== 34) break;
                ++i;
              }
            }
            I = i + 2;
            c = text.charCodeAt(i + 1);
            if (c === 13) {
              eol = true;
              if (text.charCodeAt(i + 2) === 10) ++I;
            } else if (c === 10) {
              eol = true;
            }
            return text.slice(j + 1, i).replace(/""/g, "\"");
          }
  
          // common case: find next delimiter or newline
          while (I < N) {
            var k = 1;
            c = text.charCodeAt(I++);
            if (c === 10) eol = true; // \n
            else if (c === 13) { eol = true; if (text.charCodeAt(I) === 10) ++I, ++k; } // \r|\r\n
            else if (c !== delimiterCode) continue;
            return text.slice(j, I - k);
          }
  
          // special case: last token before EOF
          return text.slice(j);
        }
  
        while ((t = token()) !== EOF) {
          var a = [];
          while (t !== EOL && t !== EOF) {
            a.push(t);
            t = token();
          }
          if (f && (a = f(a, n++)) == null) continue;
          rows.push(a);
        }
  
        return rows;
      }
  
      function format(rows, columns) {
        if (columns == null) columns = inferColumns(rows);
        return [columns.map(formatValue).join(delimiter)].concat(rows.map(function(row) {
          return columns.map(function(column) {
            return formatValue(row[column]);
          }).join(delimiter);
        })).join("\n");
      }
  
      function formatRows(rows) {
        return rows.map(formatRow).join("\n");
      }
  
      function formatRow(row) {
        return row.map(formatValue).join(delimiter);
      }
  
      function formatValue(text) {
        return text == null ? ""
            : reFormat.test(text += "") ? "\"" + text.replace(/\"/g, "\"\"") + "\""
            : text;
      }
  
      return {
        parse: parse,
        parseRows: parseRows,
        format: format,
        formatRows: formatRows
      };
    }
  
    var csv = dsv(",");
  
    var csvParse = csv.parse;
    var csvParseRows = csv.parseRows;
    var csvFormat = csv.format;
    var csvFormatRows = csv.formatRows;
  
    var tsv = dsv("\t");
  
    var tsvParse = tsv.parse;
    var tsvParseRows = tsv.parseRows;
    var tsvFormat = tsv.format;
    var tsvFormatRows = tsv.formatRows;
  
    function request(url, callback) {
      var request,
          event = dispatch("beforesend", "progress", "load", "error"),
          mimeType,
          headers = map$1(),
          xhr = new XMLHttpRequest,
          user = null,
          password = null,
          response,
          responseType,
          timeout = 0;
  
      // If IE does not support CORS, use XDomainRequest.
      if (typeof XDomainRequest !== "undefined"
          && !("withCredentials" in xhr)
          && /^(http(s)?:)?\/\//.test(url)) xhr = new XDomainRequest;
  
      "onload" in xhr
          ? xhr.onload = xhr.onerror = xhr.ontimeout = respond
          : xhr.onreadystatechange = function(o) { xhr.readyState > 3 && respond(o); };
  
      function respond(o) {
        var status = xhr.status, result;
        if (!status && hasResponse(xhr)
            || status >= 200 && status < 300
            || status === 304) {
          if (response) {
            try {
              result = response.call(request, xhr);
            } catch (e) {
              event.call("error", request, e);
              return;
            }
          } else {
            result = xhr;
          }
          event.call("load", request, result);
        } else {
          event.call("error", request, o);
        }
      }
  
      xhr.onprogress = function(e) {
        event.call("progress", request, e);
      };
  
      request = {
        header: function(name, value) {
          name = (name + "").toLowerCase();
          if (arguments.length < 2) return headers.get(name);
          if (value == null) headers.remove(name);
          else headers.set(name, value + "");
          return request;
        },
  
        // If mimeType is non-null and no Accept header is set, a default is used.
        mimeType: function(value) {
          if (!arguments.length) return mimeType;
          mimeType = value == null ? null : value + "";
          return request;
        },
  
        // Specifies what type the response value should take;
        // for instance, arraybuffer, blob, document, or text.
        responseType: function(value) {
          if (!arguments.length) return responseType;
          responseType = value;
          return request;
        },
  
        timeout: function(value) {
          if (!arguments.length) return timeout;
          timeout = +value;
          return request;
        },
  
        user: function(value) {
          return arguments.length < 1 ? user : (user = value == null ? null : value + "", request);
        },
  
        password: function(value) {
          return arguments.length < 1 ? password : (password = value == null ? null : value + "", request);
        },
  
        // Specify how to convert the response content to a specific type;
        // changes the callback value on "load" events.
        response: function(value) {
          response = value;
          return request;
        },
  
        // Alias for send("GET", …).
        get: function(data, callback) {
          return request.send("GET", data, callback);
        },
  
        // Alias for send("POST", …).
        post: function(data, callback) {
          return request.send("POST", data, callback);
        },
  
        // If callback is non-null, it will be used for error and load events.
        send: function(method, data, callback) {
          xhr.open(method, url, true, user, password);
          if (mimeType != null && !headers.has("accept")) headers.set("accept", mimeType + ",*/*");
          if (xhr.setRequestHeader) headers.each(function(value, name) { xhr.setRequestHeader(name, value); });
          if (mimeType != null && xhr.overrideMimeType) xhr.overrideMimeType(mimeType);
          if (responseType != null) xhr.responseType = responseType;
          if (timeout > 0) xhr.timeout = timeout;
          if (callback == null && typeof data === "function") callback = data, data = null;
          if (callback != null && callback.length === 1) callback = fixCallback(callback);
          if (callback != null) request.on("error", callback).on("load", function(xhr) { callback(null, xhr); });
          event.call("beforesend", request, xhr);
          xhr.send(data == null ? null : data);
          return request;
        },
  
        abort: function() {
          xhr.abort();
          return request;
        },
  
        on: function() {
          var value = event.on.apply(event, arguments);
          return value === event ? request : value;
        }
      };
  
      if (callback != null) {
        if (typeof callback !== "function") throw new Error("invalid callback: " + callback);
        return request.get(callback);
      }
  
      return request;
    }
  
    function fixCallback(callback) {
      return function(error, xhr) {
        callback(error == null ? xhr : null);
      };
    }
  
    function hasResponse(xhr) {
      var type = xhr.responseType;
      return type && type !== "text"
          ? xhr.response // null on error
          : xhr.responseText; // "" on error
    }
  
    function type(defaultMimeType, response) {
      return function(url, callback) {
        var r = request(url).mimeType(defaultMimeType).response(response);
        if (callback != null) {
          if (typeof callback !== "function") throw new Error("invalid callback: " + callback);
          return r.get(callback);
        }
        return r;
      };
    }
  
    var html = type("text/html", function(xhr) {
      return document.createRange().createContextualFragment(xhr.responseText);
    });
  
    var json = type("application/json", function(xhr) {
      return JSON.parse(xhr.responseText);
    });
  
    var text = type("text/plain", function(xhr) {
      return xhr.responseText;
    });
  
    var xml = type("application/xml", function(xhr) {
      var xml = xhr.responseXML;
      if (!xml) throw new Error("parse error");
      return xml;
    });
  
    function dsv$1(defaultMimeType, parse) {
      return function(url, row, callback) {
        if (arguments.length < 3) callback = row, row = null;
        var r = request(url).mimeType(defaultMimeType);
        r.row = function(_) { return arguments.length ? r.response(responseOf(parse, row = _)) : row; };
        r.row(row);
        return callback ? r.get(callback) : r;
      };
    }
  
    function responseOf(parse, row) {
      return function(request) {
        return parse(request.responseText, row);
      };
    }
  
    var csv$1 = dsv$1("text/csv", csvParse);
  
    var tsv$1 = dsv$1("text/tab-separated-values", tsvParse);
  
    var frame = 0;
    var timeout = 0;
    var interval = 0;
    var pokeDelay = 1000;
    var taskHead;
    var taskTail;
    var clockLast = 0;
    var clockNow = 0;
    var clockSkew = 0;
    var clock = typeof performance === "object" && performance.now ? performance : Date;
    var setFrame = typeof requestAnimationFrame === "function"
            ? (clock === Date ? function(f) { requestAnimationFrame(function() { f(clock.now()); }); } : requestAnimationFrame)
            : function(f) { setTimeout(f, 17); };
    function now() {
      return clockNow || (setFrame(clearNow), clockNow = clock.now() + clockSkew);
    }
  
    function clearNow() {
      clockNow = 0;
    }
  
    function Timer() {
      this._call =
      this._time =
      this._next = null;
    }
  
    Timer.prototype = timer.prototype = {
      constructor: Timer,
      restart: function(callback, delay, time) {
        if (typeof callback !== "function") throw new TypeError("callback is not a function");
        time = (time == null ? now() : +time) + (delay == null ? 0 : +delay);
        if (!this._next && taskTail !== this) {
          if (taskTail) taskTail._next = this;
          else taskHead = this;
          taskTail = this;
        }
        this._call = callback;
        this._time = time;
        sleep();
      },
      stop: function() {
        if (this._call) {
          this._call = null;
          this._time = Infinity;
          sleep();
        }
      }
    };
  
    function timer(callback, delay, time) {
      var t = new Timer;
      t.restart(callback, delay, time);
      return t;
    }
  
    function timerFlush() {
      now(); // Get the current time, if not already set.
      ++frame; // Pretend we’ve set an alarm, if we haven’t already.
      var t = taskHead, e;
      while (t) {
        if ((e = clockNow - t._time) >= 0) t._call.call(null, e);
        t = t._next;
      }
      --frame;
    }
  
    function wake(time) {
      clockNow = (clockLast = time || clock.now()) + clockSkew;
      frame = timeout = 0;
      try {
        timerFlush();
      } finally {
        frame = 0;
        nap();
        clockNow = 0;
      }
    }
  
    function poke$1() {
      var now = clock.now(), delay = now - clockLast;
      if (delay > pokeDelay) clockSkew -= delay, clockLast = now;
    }
  
    function nap() {
      var t0, t1 = taskHead, t2, time = Infinity;
      while (t1) {
        if (t1._call) {
          if (time > t1._time) time = t1._time;
          t0 = t1, t1 = t1._next;
        } else {
          t2 = t1._next, t1._next = null;
          t1 = t0 ? t0._next = t2 : taskHead = t2;
        }
      }
      taskTail = t0;
      sleep(time);
    }
  
    function sleep(time) {
      if (frame) return; // Soonest alarm already set, or will be.
      if (timeout) timeout = clearTimeout(timeout);
      var delay = time - clockNow;
      if (delay > 24) {
        if (time < Infinity) timeout = setTimeout(wake, delay);
        if (interval) interval = clearInterval(interval);
      } else {
        if (!interval) interval = setInterval(poke$1, pokeDelay);
        frame = 1, setFrame(wake);
      }
    }
  
    function timeout$1(callback, delay, time) {
      var t = new Timer;
      delay = delay == null ? 0 : +delay;
      t.restart(function(elapsed) {
        t.stop();
        callback(elapsed + delay);
      }, delay, time);
      return t;
    }
  
    function interval$1(callback, delay, time) {
      var t = new Timer, total = delay;
      if (delay == null) return t.restart(callback, delay, time), t;
      delay = +delay, time = time == null ? now() : +time;
      t.restart(function tick(elapsed) {
        elapsed += total;
        t.restart(tick, total += delay, time);
        callback(elapsed);
      }, delay, time);
      return t;
    }
  
  var   t0$1 = new Date;
  var   t1$1 = new Date;
    function newInterval(floori, offseti, count, field) {
  
      function interval(date) {
        return floori(date = new Date(+date)), date;
      }
  
      interval.floor = interval;
  
      interval.ceil = function(date) {
        return floori(date = new Date(date - 1)), offseti(date, 1), floori(date), date;
      };
  
      interval.round = function(date) {
        var d0 = interval(date),
            d1 = interval.ceil(date);
        return date - d0 < d1 - date ? d0 : d1;
      };
  
      interval.offset = function(date, step) {
        return offseti(date = new Date(+date), step == null ? 1 : Math.floor(step)), date;
      };
  
      interval.range = function(start, stop, step) {
        var range = [];
        start = interval.ceil(start);
        step = step == null ? 1 : Math.floor(step);
        if (!(start < stop) || !(step > 0)) return range; // also handles Invalid Date
        do range.push(new Date(+start)); while (offseti(start, step), floori(start), start < stop)
        return range;
      };
  
      interval.filter = function(test) {
        return newInterval(function(date) {
          while (floori(date), !test(date)) date.setTime(date - 1);
        }, function(date, step) {
          while (--step >= 0) while (offseti(date, 1), !test(date));
        });
      };
  
      if (count) {
        interval.count = function(start, end) {
          t0$1.setTime(+start), t1$1.setTime(+end);
          floori(t0$1), floori(t1$1);
          return Math.floor(count(t0$1, t1$1));
        };
  
        interval.every = function(step) {
          step = Math.floor(step);
          return !isFinite(step) || !(step > 0) ? null
              : !(step > 1) ? interval
              : interval.filter(field
                  ? function(d) { return field(d) % step === 0; }
                  : function(d) { return interval.count(0, d) % step === 0; });
        };
      }
  
      return interval;
    }
  
    var millisecond = newInterval(function() {
      // noop
    }, function(date, step) {
      date.setTime(+date + step);
    }, function(start, end) {
      return end - start;
    });
  
    // An optimized implementation for this simple case.
    millisecond.every = function(k) {
      k = Math.floor(k);
      if (!isFinite(k) || !(k > 0)) return null;
      if (!(k > 1)) return millisecond;
      return newInterval(function(date) {
        date.setTime(Math.floor(date / k) * k);
      }, function(date, step) {
        date.setTime(+date + step * k);
      }, function(start, end) {
        return (end - start) / k;
      });
    };
  
    var milliseconds = millisecond.range;
  
    var durationSecond = 1e3;
    var durationMinute = 6e4;
    var durationHour = 36e5;
    var durationDay = 864e5;
    var durationWeek = 6048e5;
  
    var second = newInterval(function(date) {
      date.setTime(Math.floor(date / durationSecond) * durationSecond);
    }, function(date, step) {
      date.setTime(+date + step * durationSecond);
    }, function(start, end) {
      return (end - start) / durationSecond;
    }, function(date) {
      return date.getUTCSeconds();
    });
  
    var seconds = second.range;
  
    var minute = newInterval(function(date) {
      date.setTime(Math.floor(date / durationMinute) * durationMinute);
    }, function(date, step) {
      date.setTime(+date + step * durationMinute);
    }, function(start, end) {
      return (end - start) / durationMinute;
    }, function(date) {
      return date.getMinutes();
    });
  
    var minutes = minute.range;
  
    var hour = newInterval(function(date) {
      var offset = date.getTimezoneOffset() * durationMinute % durationHour;
      if (offset < 0) offset += durationHour;
      date.setTime(Math.floor((+date - offset) / durationHour) * durationHour + offset);
    }, function(date, step) {
      date.setTime(+date + step * durationHour);
    }, function(start, end) {
      return (end - start) / durationHour;
    }, function(date) {
      return date.getHours();
    });
  
    var hours = hour.range;
  
    var day = newInterval(function(date) {
      date.setHours(0, 0, 0, 0);
    }, function(date, step) {
      date.setDate(date.getDate() + step);
    }, function(start, end) {
      return (end - start - (end.getTimezoneOffset() - start.getTimezoneOffset()) * durationMinute) / durationDay;
    }, function(date) {
      return date.getDate() - 1;
    });
  
    var days = day.range;
  
    function weekday(i) {
      return newInterval(function(date) {
        date.setDate(date.getDate() - (date.getDay() + 7 - i) % 7);
        date.setHours(0, 0, 0, 0);
      }, function(date, step) {
        date.setDate(date.getDate() + step * 7);
      }, function(start, end) {
        return (end - start - (end.getTimezoneOffset() - start.getTimezoneOffset()) * durationMinute) / durationWeek;
      });
    }
  
    var timeWeek = weekday(0);
    var timeMonday = weekday(1);
    var tuesday = weekday(2);
    var wednesday = weekday(3);
    var thursday = weekday(4);
    var friday = weekday(5);
    var saturday = weekday(6);
  
    var sundays = timeWeek.range;
    var mondays = timeMonday.range;
    var tuesdays = tuesday.range;
    var wednesdays = wednesday.range;
    var thursdays = thursday.range;
    var fridays = friday.range;
    var saturdays = saturday.range;
  
    var month = newInterval(function(date) {
      date.setDate(1);
      date.setHours(0, 0, 0, 0);
    }, function(date, step) {
      date.setMonth(date.getMonth() + step);
    }, function(start, end) {
      return end.getMonth() - start.getMonth() + (end.getFullYear() - start.getFullYear()) * 12;
    }, function(date) {
      return date.getMonth();
    });
  
    var months = month.range;
  
    var year = newInterval(function(date) {
      date.setMonth(0, 1);
      date.setHours(0, 0, 0, 0);
    }, function(date, step) {
      date.setFullYear(date.getFullYear() + step);
    }, function(start, end) {
      return end.getFullYear() - start.getFullYear();
    }, function(date) {
      return date.getFullYear();
    });
  
    // An optimized implementation for this simple case.
    year.every = function(k) {
      return !isFinite(k = Math.floor(k)) || !(k > 0) ? null : newInterval(function(date) {
        date.setFullYear(Math.floor(date.getFullYear() / k) * k);
        date.setMonth(0, 1);
        date.setHours(0, 0, 0, 0);
      }, function(date, step) {
        date.setFullYear(date.getFullYear() + step * k);
      });
    };
  
    var years = year.range;
  
    var utcMinute = newInterval(function(date) {
      date.setUTCSeconds(0, 0);
    }, function(date, step) {
      date.setTime(+date + step * durationMinute);
    }, function(start, end) {
      return (end - start) / durationMinute;
    }, function(date) {
      return date.getUTCMinutes();
    });
  
    var utcMinutes = utcMinute.range;
  
    var utcHour = newInterval(function(date) {
      date.setUTCMinutes(0, 0, 0);
    }, function(date, step) {
      date.setTime(+date + step * durationHour);
    }, function(start, end) {
      return (end - start) / durationHour;
    }, function(date) {
      return date.getUTCHours();
    });
  
    var utcHours = utcHour.range;
  
    var utcDay = newInterval(function(date) {
      date.setUTCHours(0, 0, 0, 0);
    }, function(date, step) {
      date.setUTCDate(date.getUTCDate() + step);
    }, function(start, end) {
      return (end - start) / durationDay;
    }, function(date) {
      return date.getUTCDate() - 1;
    });
  
    var utcDays = utcDay.range;
  
    function utcWeekday(i) {
      return newInterval(function(date) {
        date.setUTCDate(date.getUTCDate() - (date.getUTCDay() + 7 - i) % 7);
        date.setUTCHours(0, 0, 0, 0);
      }, function(date, step) {
        date.setUTCDate(date.getUTCDate() + step * 7);
      }, function(start, end) {
        return (end - start) / durationWeek;
      });
    }
  
    var utcWeek = utcWeekday(0);
    var utcMonday = utcWeekday(1);
    var utcTuesday = utcWeekday(2);
    var utcWednesday = utcWeekday(3);
    var utcThursday = utcWeekday(4);
    var utcFriday = utcWeekday(5);
    var utcSaturday = utcWeekday(6);
  
    var utcSundays = utcWeek.range;
    var utcMondays = utcMonday.range;
    var utcTuesdays = utcTuesday.range;
    var utcWednesdays = utcWednesday.range;
    var utcThursdays = utcThursday.range;
    var utcFridays = utcFriday.range;
    var utcSaturdays = utcSaturday.range;
  
    var utcMonth = newInterval(function(date) {
      date.setUTCDate(1);
      date.setUTCHours(0, 0, 0, 0);
    }, function(date, step) {
      date.setUTCMonth(date.getUTCMonth() + step);
    }, function(start, end) {
      return end.getUTCMonth() - start.getUTCMonth() + (end.getUTCFullYear() - start.getUTCFullYear()) * 12;
    }, function(date) {
      return date.getUTCMonth();
    });
  
    var utcMonths = utcMonth.range;
  
    var utcYear = newInterval(function(date) {
      date.setUTCMonth(0, 1);
      date.setUTCHours(0, 0, 0, 0);
    }, function(date, step) {
      date.setUTCFullYear(date.getUTCFullYear() + step);
    }, function(start, end) {
      return end.getUTCFullYear() - start.getUTCFullYear();
    }, function(date) {
      return date.getUTCFullYear();
    });
  
    // An optimized implementation for this simple case.
    utcYear.every = function(k) {
      return !isFinite(k = Math.floor(k)) || !(k > 0) ? null : newInterval(function(date) {
        date.setUTCFullYear(Math.floor(date.getUTCFullYear() / k) * k);
        date.setUTCMonth(0, 1);
        date.setUTCHours(0, 0, 0, 0);
      }, function(date, step) {
        date.setUTCFullYear(date.getUTCFullYear() + step * k);
      });
    };
  
    var utcYears = utcYear.range;
  
    // Computes the decimal coefficient and exponent of the specified number x with
    // significant digits p, where x is positive and p is in [1, 21] or undefined.
    // For example, formatDecimal(1.23) returns ["123", 0].
    function formatDecimal(x, p) {
      if ((i = (x = p ? x.toExponential(p - 1) : x.toExponential()).indexOf("e")) < 0) return null; // NaN, ±Infinity
      var i, coefficient = x.slice(0, i);
  
      // The string returned by toExponential either has the form \d\.\d+e[-+]\d+
      // (e.g., 1.2e+3) or the form \de[-+]\d+ (e.g., 1e+3).
      return [
        coefficient.length > 1 ? coefficient[0] + coefficient.slice(2) : coefficient,
        +x.slice(i + 1)
      ];
    }
  
    function exponent$1(x) {
      return x = formatDecimal(Math.abs(x)), x ? x[1] : NaN;
    }
  
    function formatGroup(grouping, thousands) {
      return function(value, width) {
        var i = value.length,
            t = [],
            j = 0,
            g = grouping[0],
            length = 0;
  
        while (i > 0 && g > 0) {
          if (length + g + 1 > width) g = Math.max(1, width - length);
          t.push(value.substring(i -= g, i + g));
          if ((length += g + 1) > width) break;
          g = grouping[j = (j + 1) % grouping.length];
        }
  
        return t.reverse().join(thousands);
      };
    }
  
    function formatDefault(x, p) {
      x = x.toPrecision(p);
  
      out: for (var n = x.length, i = 1, i0 = -1, i1; i < n; ++i) {
        switch (x[i]) {
          case ".": i0 = i1 = i; break;
          case "0": if (i0 === 0) i0 = i; i1 = i; break;
          case "e": break out;
          default: if (i0 > 0) i0 = 0; break;
        }
      }
  
      return i0 > 0 ? x.slice(0, i0) + x.slice(i1 + 1) : x;
    }
  
    var prefixExponent;
  
    function formatPrefixAuto(x, p) {
      var d = formatDecimal(x, p);
      if (!d) return x + "";
      var coefficient = d[0],
          exponent = d[1],
          i = exponent - (prefixExponent = Math.max(-8, Math.min(8, Math.floor(exponent / 3))) * 3) + 1,
          n = coefficient.length;
      return i === n ? coefficient
          : i > n ? coefficient + new Array(i - n + 1).join("0")
          : i > 0 ? coefficient.slice(0, i) + "." + coefficient.slice(i)
          : "0." + new Array(1 - i).join("0") + formatDecimal(x, Math.max(0, p + i - 1))[0]; // less than 1y!
    }
  
    function formatRounded(x, p) {
      var d = formatDecimal(x, p);
      if (!d) return x + "";
      var coefficient = d[0],
          exponent = d[1];
      return exponent < 0 ? "0." + new Array(-exponent).join("0") + coefficient
          : coefficient.length > exponent + 1 ? coefficient.slice(0, exponent + 1) + "." + coefficient.slice(exponent + 1)
          : coefficient + new Array(exponent - coefficient.length + 2).join("0");
    }
  
    var formatTypes = {
      "": formatDefault,
      "%": function(x, p) { return (x * 100).toFixed(p); },
      "b": function(x) { return Math.round(x).toString(2); },
      "c": function(x) { return x + ""; },
      "d": function(x) { return Math.round(x).toString(10); },
      "e": function(x, p) { return x.toExponential(p); },
      "f": function(x, p) { return x.toFixed(p); },
      "g": function(x, p) { return x.toPrecision(p); },
      "o": function(x) { return Math.round(x).toString(8); },
      "p": function(x, p) { return formatRounded(x * 100, p); },
      "r": formatRounded,
      "s": formatPrefixAuto,
      "X": function(x) { return Math.round(x).toString(16).toUpperCase(); },
      "x": function(x) { return Math.round(x).toString(16); }
    };
  
    // [[fill]align][sign][symbol][0][width][,][.precision][type]
    var re = /^(?:(.)?([<>=^]))?([+\-\( ])?([$#])?(0)?(\d+)?(,)?(\.\d+)?([a-z%])?$/i;
  
    function formatSpecifier(specifier) {
      return new FormatSpecifier(specifier);
    }
  
    function FormatSpecifier(specifier) {
      if (!(match = re.exec(specifier))) throw new Error("invalid format: " + specifier);
  
      var match,
          fill = match[1] || " ",
          align = match[2] || ">",
          sign = match[3] || "-",
          symbol = match[4] || "",
          zero = !!match[5],
          width = match[6] && +match[6],
          comma = !!match[7],
          precision = match[8] && +match[8].slice(1),
          type = match[9] || "";
  
      // The "n" type is an alias for ",g".
      if (type === "n") comma = true, type = "g";
  
      // Map invalid types to the default format.
      else if (!formatTypes[type]) type = "";
  
      // If zero fill is specified, padding goes after sign and before digits.
      if (zero || (fill === "0" && align === "=")) zero = true, fill = "0", align = "=";
  
      this.fill = fill;
      this.align = align;
      this.sign = sign;
      this.symbol = symbol;
      this.zero = zero;
      this.width = width;
      this.comma = comma;
      this.precision = precision;
      this.type = type;
    }
  
    FormatSpecifier.prototype.toString = function() {
      return this.fill
          + this.align
          + this.sign
          + this.symbol
          + (this.zero ? "0" : "")
          + (this.width == null ? "" : Math.max(1, this.width | 0))
          + (this.comma ? "," : "")
          + (this.precision == null ? "" : "." + Math.max(0, this.precision | 0))
          + this.type;
    };
  
    var prefixes = ["y","z","a","f","p","n","\xB5","m","","k","M","G","T","P","E","Z","Y"];
  
    function identity$3(x) {
      return x;
    }
  
    function formatLocale(locale) {
      var group = locale.grouping && locale.thousands ? formatGroup(locale.grouping, locale.thousands) : identity$3,
          currency = locale.currency,
          decimal = locale.decimal;
  
      function newFormat(specifier) {
        specifier = formatSpecifier(specifier);
  
        var fill = specifier.fill,
            align = specifier.align,
            sign = specifier.sign,
            symbol = specifier.symbol,
            zero = specifier.zero,
            width = specifier.width,
            comma = specifier.comma,
            precision = specifier.precision,
            type = specifier.type;
  
        // Compute the prefix and suffix.
        // For SI-prefix, the suffix is lazily computed.
        var prefix = symbol === "$" ? currency[0] : symbol === "#" && /[boxX]/.test(type) ? "0" + type.toLowerCase() : "",
            suffix = symbol === "$" ? currency[1] : /[%p]/.test(type) ? "%" : "";
  
        // What format function should we use?
        // Is this an integer type?
        // Can this type generate exponential notation?
        var formatType = formatTypes[type],
            maybeSuffix = !type || /[defgprs%]/.test(type);
  
        // Set the default precision if not specified,
        // or clamp the specified precision to the supported range.
        // For significant precision, it must be in [1, 21].
        // For fixed precision, it must be in [0, 20].
        precision = precision == null ? (type ? 6 : 12)
            : /[gprs]/.test(type) ? Math.max(1, Math.min(21, precision))
            : Math.max(0, Math.min(20, precision));
  
        function format(value) {
          var valuePrefix = prefix,
              valueSuffix = suffix,
              i, n, c;
  
          if (type === "c") {
            valueSuffix = formatType(value) + valueSuffix;
            value = "";
          } else {
            value = +value;
  
            // Convert negative to positive, and compute the prefix.
            // Note that -0 is not less than 0, but 1 / -0 is!
            var valueNegative = (value < 0 || 1 / value < 0) && (value *= -1, true);
  
            // Perform the initial formatting.
            value = formatType(value, precision);
  
            // If the original value was negative, it may be rounded to zero during
            // formatting; treat this as (positive) zero.
            if (valueNegative) {
              i = -1, n = value.length;
              valueNegative = false;
              while (++i < n) {
                if (c = value.charCodeAt(i), (48 < c && c < 58)
                    || (type === "x" && 96 < c && c < 103)
                    || (type === "X" && 64 < c && c < 71)) {
                  valueNegative = true;
                  break;
                }
              }
            }
  
            // Compute the prefix and suffix.
            valuePrefix = (valueNegative ? (sign === "(" ? sign : "-") : sign === "-" || sign === "(" ? "" : sign) + valuePrefix;
            valueSuffix = valueSuffix + (type === "s" ? prefixes[8 + prefixExponent / 3] : "") + (valueNegative && sign === "(" ? ")" : "");
  
            // Break the formatted value into the integer “value” part that can be
            // grouped, and fractional or exponential “suffix” part that is not.
            if (maybeSuffix) {
              i = -1, n = value.length;
              while (++i < n) {
                if (c = value.charCodeAt(i), 48 > c || c > 57) {
                  valueSuffix = (c === 46 ? decimal + value.slice(i + 1) : value.slice(i)) + valueSuffix;
                  value = value.slice(0, i);
                  break;
                }
              }
            }
          }
  
          // If the fill character is not "0", grouping is applied before padding.
          if (comma && !zero) value = group(value, Infinity);
  
          // Compute the padding.
          var length = valuePrefix.length + value.length + valueSuffix.length,
              padding = length < width ? new Array(width - length + 1).join(fill) : "";
  
          // If the fill character is "0", grouping is applied after padding.
          if (comma && zero) value = group(padding + value, padding.length ? width - valueSuffix.length : Infinity), padding = "";
  
          // Reconstruct the final output based on the desired alignment.
          switch (align) {
            case "<": return valuePrefix + value + valueSuffix + padding;
            case "=": return valuePrefix + padding + value + valueSuffix;
            case "^": return padding.slice(0, length = padding.length >> 1) + valuePrefix + value + valueSuffix + padding.slice(length);
          }
          return padding + valuePrefix + value + valueSuffix;
        }
  
        format.toString = function() {
          return specifier + "";
        };
  
        return format;
      }
  
      function formatPrefix(specifier, value) {
        var f = newFormat((specifier = formatSpecifier(specifier), specifier.type = "f", specifier)),
            e = Math.max(-8, Math.min(8, Math.floor(exponent$1(value) / 3))) * 3,
            k = Math.pow(10, -e),
            prefix = prefixes[8 + e / 3];
        return function(value) {
          return f(k * value) + prefix;
        };
      }
  
      return {
        format: newFormat,
        formatPrefix: formatPrefix
      };
    }
  
    var locale;
    exports.format;
    exports.formatPrefix;
  
    defaultLocale({
      decimal: ".",
      thousands: ",",
      grouping: [3],
      currency: ["$", ""]
    });
  
    function defaultLocale(definition) {
      locale = formatLocale(definition);
      exports.format = locale.format;
      exports.formatPrefix = locale.formatPrefix;
      return locale;
    }
  
    function precisionFixed(step) {
      return Math.max(0, -exponent$1(Math.abs(step)));
    }
  
    function precisionPrefix(step, value) {
      return Math.max(0, Math.max(-8, Math.min(8, Math.floor(exponent$1(value) / 3))) * 3 - exponent$1(Math.abs(step)));
    }
  
    function precisionRound(step, max) {
      step = Math.abs(step), max = Math.abs(max) - step;
      return Math.max(0, exponent$1(max) - exponent$1(step)) + 1;
    }
  
    function localDate(d) {
      if (0 <= d.y && d.y < 100) {
        var date = new Date(-1, d.m, d.d, d.H, d.M, d.S, d.L);
        date.setFullYear(d.y);
        return date;
      }
      return new Date(d.y, d.m, d.d, d.H, d.M, d.S, d.L);
    }
  
    function utcDate(d) {
      if (0 <= d.y && d.y < 100) {
        var date = new Date(Date.UTC(-1, d.m, d.d, d.H, d.M, d.S, d.L));
        date.setUTCFullYear(d.y);
        return date;
      }
      return new Date(Date.UTC(d.y, d.m, d.d, d.H, d.M, d.S, d.L));
    }
  
    function newYear(y) {
      return {y: y, m: 0, d: 1, H: 0, M: 0, S: 0, L: 0};
    }
  
    function formatLocale$1(locale) {
      var locale_dateTime = locale.dateTime,
          locale_date = locale.date,
          locale_time = locale.time,
          locale_periods = locale.periods,
          locale_weekdays = locale.days,
          locale_shortWeekdays = locale.shortDays,
          locale_months = locale.months,
          locale_shortMonths = locale.shortMonths;
  
      var periodRe = formatRe(locale_periods),
          periodLookup = formatLookup(locale_periods),
          weekdayRe = formatRe(locale_weekdays),
          weekdayLookup = formatLookup(locale_weekdays),
          shortWeekdayRe = formatRe(locale_shortWeekdays),
          shortWeekdayLookup = formatLookup(locale_shortWeekdays),
          monthRe = formatRe(locale_months),
          monthLookup = formatLookup(locale_months),
          shortMonthRe = formatRe(locale_shortMonths),
          shortMonthLookup = formatLookup(locale_shortMonths);
  
      var formats = {
        "a": formatShortWeekday,
        "A": formatWeekday,
        "b": formatShortMonth,
        "B": formatMonth,
        "c": null,
        "d": formatDayOfMonth,
        "e": formatDayOfMonth,
        "H": formatHour24,
        "I": formatHour12,
        "j": formatDayOfYear,
        "L": formatMilliseconds,
        "m": formatMonthNumber,
        "M": formatMinutes,
        "p": formatPeriod,
        "S": formatSeconds,
        "U": formatWeekNumberSunday,
        "w": formatWeekdayNumber,
        "W": formatWeekNumberMonday,
        "x": null,
        "X": null,
        "y": formatYear,
        "Y": formatFullYear,
        "Z": formatZone,
        "%": formatLiteralPercent
      };
  
      var utcFormats = {
        "a": formatUTCShortWeekday,
        "A": formatUTCWeekday,
        "b": formatUTCShortMonth,
        "B": formatUTCMonth,
        "c": null,
        "d": formatUTCDayOfMonth,
        "e": formatUTCDayOfMonth,
        "H": formatUTCHour24,
        "I": formatUTCHour12,
        "j": formatUTCDayOfYear,
        "L": formatUTCMilliseconds,
        "m": formatUTCMonthNumber,
        "M": formatUTCMinutes,
        "p": formatUTCPeriod,
        "S": formatUTCSeconds,
        "U": formatUTCWeekNumberSunday,
        "w": formatUTCWeekdayNumber,
        "W": formatUTCWeekNumberMonday,
        "x": null,
        "X": null,
        "y": formatUTCYear,
        "Y": formatUTCFullYear,
        "Z": formatUTCZone,
        "%": formatLiteralPercent
      };
  
      var parses = {
        "a": parseShortWeekday,
        "A": parseWeekday,
        "b": parseShortMonth,
        "B": parseMonth,
        "c": parseLocaleDateTime,
        "d": parseDayOfMonth,
        "e": parseDayOfMonth,
        "H": parseHour24,
        "I": parseHour24,
        "j": parseDayOfYear,
        "L": parseMilliseconds,
        "m": parseMonthNumber,
        "M": parseMinutes,
        "p": parsePeriod,
        "S": parseSeconds,
        "U": parseWeekNumberSunday,
        "w": parseWeekdayNumber,
        "W": parseWeekNumberMonday,
        "x": parseLocaleDate,
        "X": parseLocaleTime,
        "y": parseYear,
        "Y": parseFullYear,
        "Z": parseZone,
        "%": parseLiteralPercent
      };
  
      // These recursive directive definitions must be deferred.
      formats.x = newFormat(locale_date, formats);
      formats.X = newFormat(locale_time, formats);
      formats.c = newFormat(locale_dateTime, formats);
      utcFormats.x = newFormat(locale_date, utcFormats);
      utcFormats.X = newFormat(locale_time, utcFormats);
      utcFormats.c = newFormat(locale_dateTime, utcFormats);
  
      function newFormat(specifier, formats) {
        return function(date) {
          var string = [],
              i = -1,
              j = 0,
              n = specifier.length,
              c,
              pad,
              format;
  
          if (!(date instanceof Date)) date = new Date(+date);
  
          while (++i < n) {
            if (specifier.charCodeAt(i) === 37) {
              string.push(specifier.slice(j, i));
              if ((pad = pads[c = specifier.charAt(++i)]) != null) c = specifier.charAt(++i);
              else pad = c === "e" ? " " : "0";
              if (format = formats[c]) c = format(date, pad);
              string.push(c);
              j = i + 1;
            }
          }
  
          string.push(specifier.slice(j, i));
          return string.join("");
        };
      }
  
      function newParse(specifier, newDate) {
        return function(string) {
          var d = newYear(1900),
              i = parseSpecifier(d, specifier, string += "", 0);
          if (i != string.length) return null;
  
          // The am-pm flag is 0 for AM, and 1 for PM.
          if ("p" in d) d.H = d.H % 12 + d.p * 12;
  
          // Convert day-of-week and week-of-year to day-of-year.
          if ("W" in d || "U" in d) {
            if (!("w" in d)) d.w = "W" in d ? 1 : 0;
            var day = "Z" in d ? utcDate(newYear(d.y)).getUTCDay() : newDate(newYear(d.y)).getDay();
            d.m = 0;
            d.d = "W" in d ? (d.w + 6) % 7 + d.W * 7 - (day + 5) % 7 : d.w + d.U * 7 - (day + 6) % 7;
          }
  
          // If a time zone is specified, all fields are interpreted as UTC and then
          // offset according to the specified time zone.
          if ("Z" in d) {
            d.H += d.Z / 100 | 0;
            d.M += d.Z % 100;
            return utcDate(d);
          }
  
          // Otherwise, all fields are in local time.
          return newDate(d);
        };
      }
  
      function parseSpecifier(d, specifier, string, j) {
        var i = 0,
            n = specifier.length,
            m = string.length,
            c,
            parse;
  
        while (i < n) {
          if (j >= m) return -1;
          c = specifier.charCodeAt(i++);
          if (c === 37) {
            c = specifier.charAt(i++);
            parse = parses[c in pads ? specifier.charAt(i++) : c];
            if (!parse || ((j = parse(d, string, j)) < 0)) return -1;
          } else if (c != string.charCodeAt(j++)) {
            return -1;
          }
        }
  
        return j;
      }
  
      function parsePeriod(d, string, i) {
        var n = periodRe.exec(string.slice(i));
        return n ? (d.p = periodLookup[n[0].toLowerCase()], i + n[0].length) : -1;
      }
  
      function parseShortWeekday(d, string, i) {
        var n = shortWeekdayRe.exec(string.slice(i));
        return n ? (d.w = shortWeekdayLookup[n[0].toLowerCase()], i + n[0].length) : -1;
      }
  
      function parseWeekday(d, string, i) {
        var n = weekdayRe.exec(string.slice(i));
        return n ? (d.w = weekdayLookup[n[0].toLowerCase()], i + n[0].length) : -1;
      }
  
      function parseShortMonth(d, string, i) {
        var n = shortMonthRe.exec(string.slice(i));
        return n ? (d.m = shortMonthLookup[n[0].toLowerCase()], i + n[0].length) : -1;
      }
  
      function parseMonth(d, string, i) {
        var n = monthRe.exec(string.slice(i));
        return n ? (d.m = monthLookup[n[0].toLowerCase()], i + n[0].length) : -1;
      }
  
      function parseLocaleDateTime(d, string, i) {
        return parseSpecifier(d, locale_dateTime, string, i);
      }
  
      function parseLocaleDate(d, string, i) {
        return parseSpecifier(d, locale_date, string, i);
      }
  
      function parseLocaleTime(d, string, i) {
        return parseSpecifier(d, locale_time, string, i);
      }
  
      function formatShortWeekday(d) {
        return locale_shortWeekdays[d.getDay()];
      }
  
      function formatWeekday(d) {
        return locale_weekdays[d.getDay()];
      }
  
      function formatShortMonth(d) {
        return locale_shortMonths[d.getMonth()];
      }
  
      function formatMonth(d) {
        return locale_months[d.getMonth()];
      }
  
      function formatPeriod(d) {
        return locale_periods[+(d.getHours() >= 12)];
      }
  
      function formatUTCShortWeekday(d) {
        return locale_shortWeekdays[d.getUTCDay()];
      }
  
      function formatUTCWeekday(d) {
        return locale_weekdays[d.getUTCDay()];
      }
  
      function formatUTCShortMonth(d) {
        return locale_shortMonths[d.getUTCMonth()];
      }
  
      function formatUTCMonth(d) {
        return locale_months[d.getUTCMonth()];
      }
  
      function formatUTCPeriod(d) {
        return locale_periods[+(d.getUTCHours() >= 12)];
      }
  
      return {
        format: function(specifier) {
          var f = newFormat(specifier += "", formats);
          f.toString = function() { return specifier; };
          return f;
        },
        parse: function(specifier) {
          var p = newParse(specifier += "", localDate);
          p.toString = function() { return specifier; };
          return p;
        },
        utcFormat: function(specifier) {
          var f = newFormat(specifier += "", utcFormats);
          f.toString = function() { return specifier; };
          return f;
        },
        utcParse: function(specifier) {
          var p = newParse(specifier, utcDate);
          p.toString = function() { return specifier; };
          return p;
        }
      };
    }
  
    var pads = {"-": "", "_": " ", "0": "0"};
    var numberRe = /^\s*\d+/;
    var percentRe = /^%/;
    var requoteRe = /[\\\^\$\*\+\?\|\[\]\(\)\.\{\}]/g;
    function pad(value, fill, width) {
      var sign = value < 0 ? "-" : "",
          string = (sign ? -value : value) + "",
          length = string.length;
      return sign + (length < width ? new Array(width - length + 1).join(fill) + string : string);
    }
  
    function requote(s) {
      return s.replace(requoteRe, "\\$&");
    }
  
    function formatRe(names) {
      return new RegExp("^(?:" + names.map(requote).join("|") + ")", "i");
    }
  
    function formatLookup(names) {
      var map = {}, i = -1, n = names.length;
      while (++i < n) map[names[i].toLowerCase()] = i;
      return map;
    }
  
    function parseWeekdayNumber(d, string, i) {
      var n = numberRe.exec(string.slice(i, i + 1));
      return n ? (d.w = +n[0], i + n[0].length) : -1;
    }
  
    function parseWeekNumberSunday(d, string, i) {
      var n = numberRe.exec(string.slice(i));
      return n ? (d.U = +n[0], i + n[0].length) : -1;
    }
  
    function parseWeekNumberMonday(d, string, i) {
      var n = numberRe.exec(string.slice(i));
      return n ? (d.W = +n[0], i + n[0].length) : -1;
    }
  
    function parseFullYear(d, string, i) {
      var n = numberRe.exec(string.slice(i, i + 4));
      return n ? (d.y = +n[0], i + n[0].length) : -1;
    }
  
    function parseYear(d, string, i) {
      var n = numberRe.exec(string.slice(i, i + 2));
      return n ? (d.y = +n[0] + (+n[0] > 68 ? 1900 : 2000), i + n[0].length) : -1;
    }
  
    function parseZone(d, string, i) {
      var n = /^(Z)|([+-]\d\d)(?:\:?(\d\d))?/.exec(string.slice(i, i + 6));
      return n ? (d.Z = n[1] ? 0 : -(n[2] + (n[3] || "00")), i + n[0].length) : -1;
    }
  
    function parseMonthNumber(d, string, i) {
      var n = numberRe.exec(string.slice(i, i + 2));
      return n ? (d.m = n[0] - 1, i + n[0].length) : -1;
    }
  
    function parseDayOfMonth(d, string, i) {
      var n = numberRe.exec(string.slice(i, i + 2));
      return n ? (d.d = +n[0], i + n[0].length) : -1;
    }
  
    function parseDayOfYear(d, string, i) {
      var n = numberRe.exec(string.slice(i, i + 3));
      return n ? (d.m = 0, d.d = +n[0], i + n[0].length) : -1;
    }
  
    function parseHour24(d, string, i) {
      var n = numberRe.exec(string.slice(i, i + 2));
      return n ? (d.H = +n[0], i + n[0].length) : -1;
    }
  
    function parseMinutes(d, string, i) {
      var n = numberRe.exec(string.slice(i, i + 2));
      return n ? (d.M = +n[0], i + n[0].length) : -1;
    }
  
    function parseSeconds(d, string, i) {
      var n = numberRe.exec(string.slice(i, i + 2));
      return n ? (d.S = +n[0], i + n[0].length) : -1;
    }
  
    function parseMilliseconds(d, string, i) {
      var n = numberRe.exec(string.slice(i, i + 3));
      return n ? (d.L = +n[0], i + n[0].length) : -1;
    }
  
    function parseLiteralPercent(d, string, i) {
      var n = percentRe.exec(string.slice(i, i + 1));
      return n ? i + n[0].length : -1;
    }
  
    function formatDayOfMonth(d, p) {
      return pad(d.getDate(), p, 2);
    }
  
    function formatHour24(d, p) {
      return pad(d.getHours(), p, 2);
    }
  
    function formatHour12(d, p) {
      return pad(d.getHours() % 12 || 12, p, 2);
    }
  
    function formatDayOfYear(d, p) {
      return pad(1 + day.count(year(d), d), p, 3);
    }
  
    function formatMilliseconds(d, p) {
      return pad(d.getMilliseconds(), p, 3);
    }
  
    function formatMonthNumber(d, p) {
      return pad(d.getMonth() + 1, p, 2);
    }
  
    function formatMinutes(d, p) {
      return pad(d.getMinutes(), p, 2);
    }
  
    function formatSeconds(d, p) {
      return pad(d.getSeconds(), p, 2);
    }
  
    function formatWeekNumberSunday(d, p) {
      return pad(timeWeek.count(year(d), d), p, 2);
    }
  
    function formatWeekdayNumber(d) {
      return d.getDay();
    }
  
    function formatWeekNumberMonday(d, p) {
      return pad(timeMonday.count(year(d), d), p, 2);
    }
  
    function formatYear(d, p) {
      return pad(d.getFullYear() % 100, p, 2);
    }
  
    function formatFullYear(d, p) {
      return pad(d.getFullYear() % 10000, p, 4);
    }
  
    function formatZone(d) {
      var z = d.getTimezoneOffset();
      return (z > 0 ? "-" : (z *= -1, "+"))
          + pad(z / 60 | 0, "0", 2)
          + pad(z % 60, "0", 2);
    }
  
    function formatUTCDayOfMonth(d, p) {
      return pad(d.getUTCDate(), p, 2);
    }
  
    function formatUTCHour24(d, p) {
      return pad(d.getUTCHours(), p, 2);
    }
  
    function formatUTCHour12(d, p) {
      return pad(d.getUTCHours() % 12 || 12, p, 2);
    }
  
    function formatUTCDayOfYear(d, p) {
      return pad(1 + utcDay.count(utcYear(d), d), p, 3);
    }
  
    function formatUTCMilliseconds(d, p) {
      return pad(d.getUTCMilliseconds(), p, 3);
    }
  
    function formatUTCMonthNumber(d, p) {
      return pad(d.getUTCMonth() + 1, p, 2);
    }
  
    function formatUTCMinutes(d, p) {
      return pad(d.getUTCMinutes(), p, 2);
    }
  
    function formatUTCSeconds(d, p) {
      return pad(d.getUTCSeconds(), p, 2);
    }
  
    function formatUTCWeekNumberSunday(d, p) {
      return pad(utcWeek.count(utcYear(d), d), p, 2);
    }
  
    function formatUTCWeekdayNumber(d) {
      return d.getUTCDay();
    }
  
    function formatUTCWeekNumberMonday(d, p) {
      return pad(utcMonday.count(utcYear(d), d), p, 2);
    }
  
    function formatUTCYear(d, p) {
      return pad(d.getUTCFullYear() % 100, p, 2);
    }
  
    function formatUTCFullYear(d, p) {
      return pad(d.getUTCFullYear() % 10000, p, 4);
    }
  
    function formatUTCZone() {
      return "+0000";
    }
  
    function formatLiteralPercent() {
      return "%";
    }
  
    var locale$1;
    exports.timeFormat;
    exports.timeParse;
    exports.utcFormat;
    exports.utcParse;
  
    defaultLocale$1({
      dateTime: "%x, %X",
      date: "%-m/%-d/%Y",
      time: "%-I:%M:%S %p",
      periods: ["AM", "PM"],
      days: ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"],
      shortDays: ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"],
      months: ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"],
      shortMonths: ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
    });
  
    function defaultLocale$1(definition) {
      locale$1 = formatLocale$1(definition);
      exports.timeFormat = locale$1.format;
      exports.timeParse = locale$1.parse;
      exports.utcFormat = locale$1.utcFormat;
      exports.utcParse = locale$1.utcParse;
      return locale$1;
    }
  
    var isoSpecifier = "%Y-%m-%dT%H:%M:%S.%LZ";
  
    function formatIsoNative(date) {
      return date.toISOString();
    }
  
    var formatIso = Date.prototype.toISOString
        ? formatIsoNative
        : exports.utcFormat(isoSpecifier);
  
    function parseIsoNative(string) {
      var date = new Date(string);
      return isNaN(date) ? null : date;
    }
  
    var parseIso = +new Date("2000-01-01T00:00:00.000Z")
        ? parseIsoNative
        : exports.utcParse(isoSpecifier);
  
    var array$2 = Array.prototype;
  
    var map$2 = array$2.map;
    var slice$3 = array$2.slice;
  
    var implicit = {name: "implicit"};
  
    function ordinal(range) {
      var index = map$1(),
          domain = [],
          unknown = implicit;
  
      range = range == null ? [] : slice$3.call(range);
  
      function scale(d) {
        var key = d + "", i = index.get(key);
        if (!i) {
          if (unknown !== implicit) return unknown;
          index.set(key, i = domain.push(d));
        }
        return range[(i - 1) % range.length];
      }
  
      scale.domain = function(_) {
        if (!arguments.length) return domain.slice();
        domain = [], index = map$1();
        var i = -1, n = _.length, d, key;
        while (++i < n) if (!index.has(key = (d = _[i]) + "")) index.set(key, domain.push(d));
        return scale;
      };
  
      scale.range = function(_) {
        return arguments.length ? (range = slice$3.call(_), scale) : range.slice();
      };
  
      scale.unknown = function(_) {
        return arguments.length ? (unknown = _, scale) : unknown;
      };
  
      scale.copy = function() {
        return ordinal()
            .domain(domain)
            .range(range)
            .unknown(unknown);
      };
  
      return scale;
    }
  
    function band() {
      var scale = ordinal().unknown(undefined),
          domain = scale.domain,
          ordinalRange = scale.range,
          range$$ = [0, 1],
          step,
          bandwidth,
          round = false,
          paddingInner = 0,
          paddingOuter = 0,
          align = 0.5;
  
      delete scale.unknown;
  
      function rescale() {
        var n = domain().length,
            reverse = range$$[1] < range$$[0],
            start = range$$[reverse - 0],
            stop = range$$[1 - reverse];
        step = (stop - start) / Math.max(1, n - paddingInner + paddingOuter * 2);
        if (round) step = Math.floor(step);
        start += (stop - start - step * (n - paddingInner)) * align;
        bandwidth = step * (1 - paddingInner);
        if (round) start = Math.round(start), bandwidth = Math.round(bandwidth);
        var values = range(n).map(function(i) { return start + step * i; });
        return ordinalRange(reverse ? values.reverse() : values);
      }
  
      scale.domain = function(_) {
        return arguments.length ? (domain(_), rescale()) : domain();
      };
  
      scale.range = function(_) {
        return arguments.length ? (range$$ = [+_[0], +_[1]], rescale()) : range$$.slice();
      };
  
      scale.rangeRound = function(_) {
        return range$$ = [+_[0], +_[1]], round = true, rescale();
      };
  
      scale.bandwidth = function() {
        return bandwidth;
      };
  
      scale.step = function() {
        return step;
      };
  
      scale.round = function(_) {
        return arguments.length ? (round = !!_, rescale()) : round;
      };
  
      scale.padding = function(_) {
        return arguments.length ? (paddingInner = paddingOuter = Math.max(0, Math.min(1, _)), rescale()) : paddingInner;
      };
  
      scale.paddingInner = function(_) {
        return arguments.length ? (paddingInner = Math.max(0, Math.min(1, _)), rescale()) : paddingInner;
      };
  
      scale.paddingOuter = function(_) {
        return arguments.length ? (paddingOuter = Math.max(0, Math.min(1, _)), rescale()) : paddingOuter;
      };
  
      scale.align = function(_) {
        return arguments.length ? (align = Math.max(0, Math.min(1, _)), rescale()) : align;
      };
  
      scale.copy = function() {
        return band()
            .domain(domain())
            .range(range$$)
            .round(round)
            .paddingInner(paddingInner)
            .paddingOuter(paddingOuter)
            .align(align);
      };
  
      return rescale();
    }
  
    function pointish(scale) {
      var copy = scale.copy;
  
      scale.padding = scale.paddingOuter;
      delete scale.paddingInner;
      delete scale.paddingOuter;
  
      scale.copy = function() {
        return pointish(copy());
      };
  
      return scale;
    }
  
    function point$4() {
      return pointish(band().paddingInner(1));
    }
  
    function constant$3(x) {
      return function() {
        return x;
      };
    }
  
    function number$1(x) {
      return +x;
    }
  
    var unit = [0, 1];
  
    function deinterpolate(a, b) {
      return (b -= (a = +a))
          ? function(x) { return (x - a) / b; }
          : constant$3(b);
    }
  
    function deinterpolateClamp(deinterpolate) {
      return function(a, b) {
        var d = deinterpolate(a = +a, b = +b);
        return function(x) { return x <= a ? 0 : x >= b ? 1 : d(x); };
      };
    }
  
    function reinterpolateClamp(reinterpolate) {
      return function(a, b) {
        var r = reinterpolate(a = +a, b = +b);
        return function(t) { return t <= 0 ? a : t >= 1 ? b : r(t); };
      };
    }
  
    function bimap(domain, range, deinterpolate, reinterpolate) {
      var d0 = domain[0], d1 = domain[1], r0 = range[0], r1 = range[1];
      if (d1 < d0) d0 = deinterpolate(d1, d0), r0 = reinterpolate(r1, r0);
      else d0 = deinterpolate(d0, d1), r0 = reinterpolate(r0, r1);
      return function(x) { return r0(d0(x)); };
    }
  
    function polymap(domain, range, deinterpolate, reinterpolate) {
      var j = Math.min(domain.length, range.length) - 1,
          d = new Array(j),
          r = new Array(j),
          i = -1;
  
      // Reverse descending domains.
      if (domain[j] < domain[0]) {
        domain = domain.slice().reverse();
        range = range.slice().reverse();
      }
  
      while (++i < j) {
        d[i] = deinterpolate(domain[i], domain[i + 1]);
        r[i] = reinterpolate(range[i], range[i + 1]);
      }
  
      return function(x) {
        var i = bisectRight(domain, x, 1, j) - 1;
        return r[i](d[i](x));
      };
    }
  
    function copy(source, target) {
      return target
          .domain(source.domain())
          .range(source.range())
          .interpolate(source.interpolate())
          .clamp(source.clamp());
    }
  
    // deinterpolate(a, b)(x) takes a domain value x in [a,b] and returns the corresponding parameter t in [0,1].
    // reinterpolate(a, b)(t) takes a parameter t in [0,1] and returns the corresponding domain value x in [a,b].
    function continuous(deinterpolate$$, reinterpolate) {
      var domain = unit,
          range = unit,
          interpolate$$ = interpolate,
          clamp = false,
          piecewise,
          output,
          input;
  
      function rescale() {
        piecewise = Math.min(domain.length, range.length) > 2 ? polymap : bimap;
        output = input = null;
        return scale;
      }
  
      function scale(x) {
        return (output || (output = piecewise(domain, range, clamp ? deinterpolateClamp(deinterpolate$$) : deinterpolate$$, interpolate$$)))(+x);
      }
  
      scale.invert = function(y) {
        return (input || (input = piecewise(range, domain, deinterpolate, clamp ? reinterpolateClamp(reinterpolate) : reinterpolate)))(+y);
      };
  
      scale.domain = function(_) {
        return arguments.length ? (domain = map$2.call(_, number$1), rescale()) : domain.slice();
      };
  
      scale.range = function(_) {
        return arguments.length ? (range = slice$3.call(_), rescale()) : range.slice();
      };
  
      scale.rangeRound = function(_) {
        return range = slice$3.call(_), interpolate$$ = interpolateRound, rescale();
      };
  
      scale.clamp = function(_) {
        return arguments.length ? (clamp = !!_, rescale()) : clamp;
      };
  
      scale.interpolate = function(_) {
        return arguments.length ? (interpolate$$ = _, rescale()) : interpolate$$;
      };
  
      return rescale();
    }
  
    function tickFormat(domain, count, specifier) {
      var start = domain[0],
          stop = domain[domain.length - 1],
          step = tickStep(start, stop, count == null ? 10 : count),
          precision;
      specifier = formatSpecifier(specifier == null ? ",f" : specifier);
      switch (specifier.type) {
        case "s": {
          var value = Math.max(Math.abs(start), Math.abs(stop));
          if (specifier.precision == null && !isNaN(precision = precisionPrefix(step, value))) specifier.precision = precision;
          return exports.formatPrefix(specifier, value);
        }
        case "":
        case "e":
        case "g":
        case "p":
        case "r": {
          if (specifier.precision == null && !isNaN(precision = precisionRound(step, Math.max(Math.abs(start), Math.abs(stop))))) specifier.precision = precision - (specifier.type === "e");
          break;
        }
        case "f":
        case "%": {
          if (specifier.precision == null && !isNaN(precision = precisionFixed(step))) specifier.precision = precision - (specifier.type === "%") * 2;
          break;
        }
      }
      return exports.format(specifier);
    }
  
    function linearish(scale) {
      var domain = scale.domain;
  
      scale.ticks = function(count) {
        var d = domain();
        return ticks(d[0], d[d.length - 1], count == null ? 10 : count);
      };
  
      scale.tickFormat = function(count, specifier) {
        return tickFormat(domain(), count, specifier);
      };
  
      scale.nice = function(count) {
        var d = domain(),
            i = d.length - 1,
            n = count == null ? 10 : count,
            start = d[0],
            stop = d[i],
            step = tickStep(start, stop, n);
  
        if (step) {
          step = tickStep(Math.floor(start / step) * step, Math.ceil(stop / step) * step, n);
          d[0] = Math.floor(start / step) * step;
          d[i] = Math.ceil(stop / step) * step;
          domain(d);
        }
  
        return scale;
      };
  
      return scale;
    }
  
    function linear$2() {
      var scale = continuous(deinterpolate, interpolateNumber);
  
      scale.copy = function() {
        return copy(scale, linear$2());
      };
  
      return linearish(scale);
    }
  
    function identity$4() {
      var domain = [0, 1];
  
      function scale(x) {
        return +x;
      }
  
      scale.invert = scale;
  
      scale.domain = scale.range = function(_) {
        return arguments.length ? (domain = map$2.call(_, number$1), scale) : domain.slice();
      };
  
      scale.copy = function() {
        return identity$4().domain(domain);
      };
  
      return linearish(scale);
    }
  
    function nice(domain, interval) {
      domain = domain.slice();
  
      var i0 = 0,
          i1 = domain.length - 1,
          x0 = domain[i0],
          x1 = domain[i1],
          t;
  
      if (x1 < x0) {
        t = i0, i0 = i1, i1 = t;
        t = x0, x0 = x1, x1 = t;
      }
  
      domain[i0] = interval.floor(x0);
      domain[i1] = interval.ceil(x1);
      return domain;
    }
  
    function deinterpolate$1(a, b) {
      return (b = Math.log(b / a))
          ? function(x) { return Math.log(x / a) / b; }
          : constant$3(b);
    }
  
    function reinterpolate(a, b) {
      return a < 0
          ? function(t) { return -Math.pow(-b, t) * Math.pow(-a, 1 - t); }
          : function(t) { return Math.pow(b, t) * Math.pow(a, 1 - t); };
    }
  
    function pow10(x) {
      return isFinite(x) ? +("1e" + x) : x < 0 ? 0 : x;
    }
  
    function powp(base) {
      return base === 10 ? pow10
          : base === Math.E ? Math.exp
          : function(x) { return Math.pow(base, x); };
    }
  
    function logp(base) {
      return base === Math.E ? Math.log
          : base === 10 && Math.log10
          || base === 2 && Math.log2
          || (base = Math.log(base), function(x) { return Math.log(x) / base; });
    }
  
    function reflect(f) {
      return function(x) {
        return -f(-x);
      };
    }
  
    function log() {
      var scale = continuous(deinterpolate$1, reinterpolate).domain([1, 10]),
          domain = scale.domain,
          base = 10,
          logs = logp(10),
          pows = powp(10);
  
      function rescale() {
        logs = logp(base), pows = powp(base);
        if (domain()[0] < 0) logs = reflect(logs), pows = reflect(pows);
        return scale;
      }
  
      scale.base = function(_) {
        return arguments.length ? (base = +_, rescale()) : base;
      };
  
      scale.domain = function(_) {
        return arguments.length ? (domain(_), rescale()) : domain();
      };
  
      scale.ticks = function(count) {
        var d = domain(),
            u = d[0],
            v = d[d.length - 1],
            r;
  
        if (r = v < u) i = u, u = v, v = i;
  
        var i = logs(u),
            j = logs(v),
            p,
            k,
            t,
            n = count == null ? 10 : +count,
            z = [];
  
        if (!(base % 1) && j - i < n) {
          i = Math.round(i) - 1, j = Math.round(j) + 1;
          if (u > 0) for (; i < j; ++i) {
            for (k = 1, p = pows(i); k < base; ++k) {
              t = p * k;
              if (t < u) continue;
              if (t > v) break;
              z.push(t);
            }
          } else for (; i < j; ++i) {
            for (k = base - 1, p = pows(i); k >= 1; --k) {
              t = p * k;
              if (t < u) continue;
              if (t > v) break;
              z.push(t);
            }
          }
        } else {
          z = ticks(i, j, Math.min(j - i, n)).map(pows);
        }
  
        return r ? z.reverse() : z;
      };
  
      scale.tickFormat = function(count, specifier) {
        if (specifier == null) specifier = base === 10 ? ".0e" : ",";
        if (typeof specifier !== "function") specifier = exports.format(specifier);
        if (count === Infinity) return specifier;
        if (count == null) count = 10;
        var k = Math.max(1, base * count / scale.ticks().length); // TODO fast estimate?
        return function(d) {
          var i = d / pows(Math.round(logs(d)));
          if (i * base < base - 0.5) i *= base;
          return i <= k ? specifier(d) : "";
        };
      };
  
      scale.nice = function() {
        return domain(nice(domain(), {
          floor: function(x) { return pows(Math.floor(logs(x))); },
          ceil: function(x) { return pows(Math.ceil(logs(x))); }
        }));
      };
  
      scale.copy = function() {
        return copy(scale, log().base(base));
      };
  
      return scale;
    }
  
    function raise(x, exponent) {
      return x < 0 ? -Math.pow(-x, exponent) : Math.pow(x, exponent);
    }
  
    function pow() {
      var exponent = 1,
          scale = continuous(deinterpolate, reinterpolate),
          domain = scale.domain;
  
      function deinterpolate(a, b) {
        return (b = raise(b, exponent) - (a = raise(a, exponent)))
            ? function(x) { return (raise(x, exponent) - a) / b; }
            : constant$3(b);
      }
  
      function reinterpolate(a, b) {
        b = raise(b, exponent) - (a = raise(a, exponent));
        return function(t) { return raise(a + b * t, 1 / exponent); };
      }
  
      scale.exponent = function(_) {
        return arguments.length ? (exponent = +_, domain(domain())) : exponent;
      };
  
      scale.copy = function() {
        return copy(scale, pow().exponent(exponent));
      };
  
      return linearish(scale);
    }
  
    function sqrt() {
      return pow().exponent(0.5);
    }
  
    function quantile() {
      var domain = [],
          range = [],
          thresholds = [];
  
      function rescale() {
        var i = 0, n = Math.max(1, range.length);
        thresholds = new Array(n - 1);
        while (++i < n) thresholds[i - 1] = threshold(domain, i / n);
        return scale;
      }
  
      function scale(x) {
        if (!isNaN(x = +x)) return range[bisectRight(thresholds, x)];
      }
  
      scale.invertExtent = function(y) {
        var i = range.indexOf(y);
        return i < 0 ? [NaN, NaN] : [
          i > 0 ? thresholds[i - 1] : domain[0],
          i < thresholds.length ? thresholds[i] : domain[domain.length - 1]
        ];
      };
  
      scale.domain = function(_) {
        if (!arguments.length) return domain.slice();
        domain = [];
        for (var i = 0, n = _.length, d; i < n; ++i) if (d = _[i], d != null && !isNaN(d = +d)) domain.push(d);
        domain.sort(ascending);
        return rescale();
      };
  
      scale.range = function(_) {
        return arguments.length ? (range = slice$3.call(_), rescale()) : range.slice();
      };
  
      scale.quantiles = function() {
        return thresholds.slice();
      };
  
      scale.copy = function() {
        return quantile()
            .domain(domain)
            .range(range);
      };
  
      return scale;
    }
  
    function quantize$1() {
      var x0 = 0,
          x1 = 1,
          n = 1,
          domain = [0.5],
          range = [0, 1];
  
      function scale(x) {
        if (x <= x) return range[bisectRight(domain, x, 0, n)];
      }
  
      function rescale() {
        var i = -1;
        domain = new Array(n);
        while (++i < n) domain[i] = ((i + 1) * x1 - (i - n) * x0) / (n + 1);
        return scale;
      }
  
      scale.domain = function(_) {
        return arguments.length ? (x0 = +_[0], x1 = +_[1], rescale()) : [x0, x1];
      };
  
      scale.range = function(_) {
        return arguments.length ? (n = (range = slice$3.call(_)).length - 1, rescale()) : range.slice();
      };
  
      scale.invertExtent = function(y) {
        var i = range.indexOf(y);
        return i < 0 ? [NaN, NaN]
            : i < 1 ? [x0, domain[0]]
            : i >= n ? [domain[n - 1], x1]
            : [domain[i - 1], domain[i]];
      };
  
      scale.copy = function() {
        return quantize$1()
            .domain([x0, x1])
            .range(range);
      };
  
      return linearish(scale);
    }
  
    function threshold$1() {
      var domain = [0.5],
          range = [0, 1],
          n = 1;
  
      function scale(x) {
        if (x <= x) return range[bisectRight(domain, x, 0, n)];
      }
  
      scale.domain = function(_) {
        return arguments.length ? (domain = slice$3.call(_), n = Math.min(domain.length, range.length - 1), scale) : domain.slice();
      };
  
      scale.range = function(_) {
        return arguments.length ? (range = slice$3.call(_), n = Math.min(domain.length, range.length - 1), scale) : range.slice();
      };
  
      scale.invertExtent = function(y) {
        var i = range.indexOf(y);
        return [domain[i - 1], domain[i]];
      };
  
      scale.copy = function() {
        return threshold$1()
            .domain(domain)
            .range(range);
      };
  
      return scale;
    }
  
  var   durationSecond$1 = 1000;
  var   durationMinute$1 = durationSecond$1 * 60;
  var   durationHour$1 = durationMinute$1 * 60;
  var   durationDay$1 = durationHour$1 * 24;
  var   durationWeek$1 = durationDay$1 * 7;
    var durationMonth = durationDay$1 * 30;
    var durationYear = durationDay$1 * 365;
    function date$1(t) {
      return new Date(t);
    }
  
    function number$2(t) {
      return t instanceof Date ? +t : +new Date(+t);
    }
  
    function calendar(year, month, week, day, hour, minute, second, millisecond, format) {
      var scale = continuous(deinterpolate, interpolateNumber),
          invert = scale.invert,
          domain = scale.domain;
  
      var formatMillisecond = format(".%L"),
          formatSecond = format(":%S"),
          formatMinute = format("%I:%M"),
          formatHour = format("%I %p"),
          formatDay = format("%a %d"),
          formatWeek = format("%b %d"),
          formatMonth = format("%B"),
          formatYear = format("%Y");
  
      var tickIntervals = [
        [second,  1,      durationSecond$1],
        [second,  5,  5 * durationSecond$1],
        [second, 15, 15 * durationSecond$1],
        [second, 30, 30 * durationSecond$1],
        [minute,  1,      durationMinute$1],
        [minute,  5,  5 * durationMinute$1],
        [minute, 15, 15 * durationMinute$1],
        [minute, 30, 30 * durationMinute$1],
        [  hour,  1,      durationHour$1  ],
        [  hour,  3,  3 * durationHour$1  ],
        [  hour,  6,  6 * durationHour$1  ],
        [  hour, 12, 12 * durationHour$1  ],
        [   day,  1,      durationDay$1   ],
        [   day,  2,  2 * durationDay$1   ],
        [  week,  1,      durationWeek$1  ],
        [ month,  1,      durationMonth ],
        [ month,  3,  3 * durationMonth ],
        [  year,  1,      durationYear  ]
      ];
  
      function tickFormat(date) {
        return (second(date) < date ? formatMillisecond
            : minute(date) < date ? formatSecond
            : hour(date) < date ? formatMinute
            : day(date) < date ? formatHour
            : month(date) < date ? (week(date) < date ? formatDay : formatWeek)
            : year(date) < date ? formatMonth
            : formatYear)(date);
      }
  
      function tickInterval(interval, start, stop, step) {
        if (interval == null) interval = 10;
  
        // If a desired tick count is specified, pick a reasonable tick interval
        // based on the extent of the domain and a rough estimate of tick size.
        // Otherwise, assume interval is already a time interval and use it.
        if (typeof interval === "number") {
          var target = Math.abs(stop - start) / interval,
              i = bisector(function(i) { return i[2]; }).right(tickIntervals, target);
          if (i === tickIntervals.length) {
            step = tickStep(start / durationYear, stop / durationYear, interval);
            interval = year;
          } else if (i) {
            i = tickIntervals[target / tickIntervals[i - 1][2] < tickIntervals[i][2] / target ? i - 1 : i];
            step = i[1];
            interval = i[0];
          } else {
            step = tickStep(start, stop, interval);
            interval = millisecond;
          }
        }
  
        return step == null ? interval : interval.every(step);
      }
  
      scale.invert = function(y) {
        return new Date(invert(y));
      };
  
      scale.domain = function(_) {
        return arguments.length ? domain(map$2.call(_, number$2)) : domain().map(date$1);
      };
  
      scale.ticks = function(interval, step) {
        var d = domain(),
            t0 = d[0],
            t1 = d[d.length - 1],
            r = t1 < t0,
            t;
        if (r) t = t0, t0 = t1, t1 = t;
        t = tickInterval(interval, t0, t1, step);
        t = t ? t.range(t0, t1 + 1) : []; // inclusive stop
        return r ? t.reverse() : t;
      };
  
      scale.tickFormat = function(count, specifier) {
        return specifier == null ? tickFormat : format(specifier);
      };
  
      scale.nice = function(interval, step) {
        var d = domain();
        return (interval = tickInterval(interval, d[0], d[d.length - 1], step))
            ? domain(nice(d, interval))
            : scale;
      };
  
      scale.copy = function() {
        return copy(scale, calendar(year, month, week, day, hour, minute, second, millisecond, format));
      };
  
      return scale;
    }
  
    function time() {
      return calendar(year, month, timeWeek, day, hour, minute, second, millisecond, exports.timeFormat).domain([new Date(2000, 0, 1), new Date(2000, 0, 2)]);
    }
  
    function utcTime() {
      return calendar(utcYear, utcMonth, utcWeek, utcDay, utcHour, utcMinute, second, millisecond, exports.utcFormat).domain([Date.UTC(2000, 0, 1), Date.UTC(2000, 0, 2)]);
    }
  
    function colors(s) {
      return s.match(/.{6}/g).map(function(x) {
        return "#" + x;
      });
    }
  
    var category10 = colors("1f77b4ff7f0e2ca02cd627289467bd8c564be377c27f7f7fbcbd2217becf");
  
    var category20b = colors("393b795254a36b6ecf9c9ede6379398ca252b5cf6bcedb9c8c6d31bd9e39e7ba52e7cb94843c39ad494ad6616be7969c7b4173a55194ce6dbdde9ed6");
  
    var category20c = colors("3182bd6baed69ecae1c6dbefe6550dfd8d3cfdae6bfdd0a231a35474c476a1d99bc7e9c0756bb19e9ac8bcbddcdadaeb636363969696bdbdbdd9d9d9");
  
    var category20 = colors("1f77b4aec7e8ff7f0effbb782ca02c98df8ad62728ff98969467bdc5b0d58c564bc49c94e377c2f7b6d27f7f7fc7c7c7bcbd22dbdb8d17becf9edae5");
  
    var cubehelix$3 = interpolateCubehelixLong(cubehelix(300, 0.5, 0.0), cubehelix(-240, 0.5, 1.0));
  
    var warm = interpolateCubehelixLong(cubehelix(-100, 0.75, 0.35), cubehelix(80, 1.50, 0.8));
  
    var cool = interpolateCubehelixLong(cubehelix(260, 0.75, 0.35), cubehelix(80, 1.50, 0.8));
  
    var rainbow = cubehelix();
  
    function rainbow$1(t) {
      if (t < 0 || t > 1) t -= Math.floor(t);
      var ts = Math.abs(t - 0.5);
      rainbow.h = 360 * t - 100;
      rainbow.s = 1.5 - 1.5 * ts;
      rainbow.l = 0.8 - 0.9 * ts;
      return rainbow + "";
    }
  
    function ramp(range) {
      var n = range.length;
      return function(t) {
        return range[Math.max(0, Math.min(n - 1, Math.floor(t * n)))];
      };
    }
  
    var viridis = ramp(colors("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"));
  
    var magma = ramp(colors("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"));
  
    var inferno = ramp(colors("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"));
  
    var plasma = ramp(colors("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"));
  
    function sequential(interpolator) {
      var x0 = 0,
          x1 = 1,
          clamp = false;
  
      function scale(x) {
        var t = (x - x0) / (x1 - x0);
        return interpolator(clamp ? Math.max(0, Math.min(1, t)) : t);
      }
  
      scale.domain = function(_) {
        return arguments.length ? (x0 = +_[0], x1 = +_[1], scale) : [x0, x1];
      };
  
      scale.clamp = function(_) {
        return arguments.length ? (clamp = !!_, scale) : clamp;
      };
  
      scale.interpolator = function(_) {
        return arguments.length ? (interpolator = _, scale) : interpolator;
      };
  
      scale.copy = function() {
        return sequential(interpolator).domain([x0, x1]).clamp(clamp);
      };
  
      return linearish(scale);
    }
  
    var xhtml = "http://www.w3.org/1999/xhtml";
  
    var namespaces = {
      svg: "http://www.w3.org/2000/svg",
      xhtml: xhtml,
      xlink: "http://www.w3.org/1999/xlink",
      xml: "http://www.w3.org/XML/1998/namespace",
      xmlns: "http://www.w3.org/2000/xmlns/"
    };
  
    function namespace(name) {
      var prefix = name += "", i = prefix.indexOf(":");
      if (i >= 0 && (prefix = name.slice(0, i)) !== "xmlns") name = name.slice(i + 1);
      return namespaces.hasOwnProperty(prefix) ? {space: namespaces[prefix], local: name} : name;
    }
  
    function creatorInherit(name) {
      return function() {
        var document = this.ownerDocument,
            uri = this.namespaceURI;
        return uri === xhtml && document.documentElement.namespaceURI === xhtml
            ? document.createElement(name)
            : document.createElementNS(uri, name);
      };
    }
  
    function creatorFixed(fullname) {
      return function() {
        return this.ownerDocument.createElementNS(fullname.space, fullname.local);
      };
    }
  
    function creator(name) {
      var fullname = namespace(name);
      return (fullname.local
          ? creatorFixed
          : creatorInherit)(fullname);
    }
  
    var nextId = 0;
  
    function local() {
      return new Local;
    }
  
    function Local() {
      this._ = "@" + (++nextId).toString(36);
    }
  
    Local.prototype = local.prototype = {
      constructor: Local,
      get: function(node) {
        var id = this._;
        while (!(id in node)) if (!(node = node.parentNode)) return;
        return node[id];
      },
      set: function(node, value) {
        return node[this._] = value;
      },
      remove: function(node) {
        return this._ in node && delete node[this._];
      },
      toString: function() {
        return this._;
      }
    };
  
    var matcher = function(selector) {
      return function() {
        return this.matches(selector);
      };
    };
  
    if (typeof document !== "undefined") {
      var element = document.documentElement;
      if (!element.matches) {
        var vendorMatches = element.webkitMatchesSelector
            || element.msMatchesSelector
            || element.mozMatchesSelector
            || element.oMatchesSelector;
        matcher = function(selector) {
          return function() {
            return vendorMatches.call(this, selector);
          };
        };
      }
    }
  
    var matcher$1 = matcher;
  
    var filterEvents = {};
  
    exports.event = null;
  
    if (typeof document !== "undefined") {
      var element$1 = document.documentElement;
      if (!("onmouseenter" in element$1)) {
        filterEvents = {mouseenter: "mouseover", mouseleave: "mouseout"};
      }
    }
  
    function filterContextListener(listener, index, group) {
      listener = contextListener(listener, index, group);
      return function(event) {
        var related = event.relatedTarget;
        if (!related || (related !== this && !(related.compareDocumentPosition(this) & 8))) {
          listener.call(this, event);
        }
      };
    }
  
    function contextListener(listener, index, group) {
      return function(event1) {
        var event0 = exports.event; // Events can be reentrant (e.g., focus).
        exports.event = event1;
        try {
          listener.call(this, this.__data__, index, group);
        } finally {
          exports.event = event0;
        }
      };
    }
  
    function parseTypenames$1(typenames) {
      return typenames.trim().split(/^|\s+/).map(function(t) {
        var name = "", i = t.indexOf(".");
        if (i >= 0) name = t.slice(i + 1), t = t.slice(0, i);
        return {type: t, name: name};
      });
    }
  
    function onRemove(typename) {
      return function() {
        var on = this.__on;
        if (!on) return;
        for (var j = 0, i = -1, m = on.length, o; j < m; ++j) {
          if (o = on[j], (!typename.type || o.type === typename.type) && o.name === typename.name) {
            this.removeEventListener(o.type, o.listener, o.capture);
          } else {
            on[++i] = o;
          }
        }
        if (++i) on.length = i;
        else delete this.__on;
      };
    }
  
    function onAdd(typename, value, capture) {
      var wrap = filterEvents.hasOwnProperty(typename.type) ? filterContextListener : contextListener;
      return function(d, i, group) {
        var on = this.__on, o, listener = wrap(value, i, group);
        if (on) for (var j = 0, m = on.length; j < m; ++j) {
          if ((o = on[j]).type === typename.type && o.name === typename.name) {
            this.removeEventListener(o.type, o.listener, o.capture);
            this.addEventListener(o.type, o.listener = listener, o.capture = capture);
            o.value = value;
            return;
          }
        }
        this.addEventListener(typename.type, listener, capture);
        o = {type: typename.type, name: typename.name, value: value, listener: listener, capture: capture};
        if (!on) this.__on = [o];
        else on.push(o);
      };
    }
  
    function selection_on(typename, value, capture) {
      var typenames = parseTypenames$1(typename + ""), i, n = typenames.length, t;
  
      if (arguments.length < 2) {
        var on = this.node().__on;
        if (on) for (var j = 0, m = on.length, o; j < m; ++j) {
          for (i = 0, o = on[j]; i < n; ++i) {
            if ((t = typenames[i]).type === o.type && t.name === o.name) {
              return o.value;
            }
          }
        }
        return;
      }
  
      on = value ? onAdd : onRemove;
      if (capture == null) capture = false;
      for (i = 0; i < n; ++i) this.each(on(typenames[i], value, capture));
      return this;
    }
  
    function customEvent(event1, listener, that, args) {
      var event0 = exports.event;
      event1.sourceEvent = exports.event;
      exports.event = event1;
      try {
        return listener.apply(that, args);
      } finally {
        exports.event = event0;
      }
    }
  
    function sourceEvent() {
      var current = exports.event, source;
      while (source = current.sourceEvent) current = source;
      return current;
    }
  
    function point$5(node, event) {
      var svg = node.ownerSVGElement || node;
  
      if (svg.createSVGPoint) {
        var point = svg.createSVGPoint();
        point.x = event.clientX, point.y = event.clientY;
        point = point.matrixTransform(node.getScreenCTM().inverse());
        return [point.x, point.y];
      }
  
      var rect = node.getBoundingClientRect();
      return [event.clientX - rect.left - node.clientLeft, event.clientY - rect.top - node.clientTop];
    }
  
    function mouse(node) {
      var event = sourceEvent();
      if (event.changedTouches) event = event.changedTouches[0];
      return point$5(node, event);
    }
  
    function none$2() {}
  
    function selector(selector) {
      return selector == null ? none$2 : function() {
        return this.querySelector(selector);
      };
    }
  
    function selection_select(select) {
      if (typeof select !== "function") select = selector(select);
  
      for (var groups = this._groups, m = groups.length, subgroups = new Array(m), j = 0; j < m; ++j) {
        for (var group = groups[j], n = group.length, subgroup = subgroups[j] = new Array(n), node, subnode, i = 0; i < n; ++i) {
          if ((node = group[i]) && (subnode = select.call(node, node.__data__, i, group))) {
            if ("__data__" in node) subnode.__data__ = node.__data__;
            subgroup[i] = subnode;
          }
        }
      }
  
      return new Selection(subgroups, this._parents);
    }
  
    function empty() {
      return [];
    }
  
    function selectorAll(selector) {
      return selector == null ? empty : function() {
        return this.querySelectorAll(selector);
      };
    }
  
    function selection_selectAll(select) {
      if (typeof select !== "function") select = selectorAll(select);
  
      for (var groups = this._groups, m = groups.length, subgroups = [], parents = [], j = 0; j < m; ++j) {
        for (var group = groups[j], n = group.length, node, i = 0; i < n; ++i) {
          if (node = group[i]) {
            subgroups.push(select.call(node, node.__data__, i, group));
            parents.push(node);
          }
        }
      }
  
      return new Selection(subgroups, parents);
    }
  
    function selection_filter(match) {
      if (typeof match !== "function") match = matcher$1(match);
  
      for (var groups = this._groups, m = groups.length, subgroups = new Array(m), j = 0; j < m; ++j) {
        for (var group = groups[j], n = group.length, subgroup = subgroups[j] = [], node, i = 0; i < n; ++i) {
          if ((node = group[i]) && match.call(node, node.__data__, i, group)) {
            subgroup.push(node);
          }
        }
      }
  
      return new Selection(subgroups, this._parents);
    }
  
    function sparse(update) {
      return new Array(update.length);
    }
  
    function selection_enter() {
      return new Selection(this._enter || this._groups.map(sparse), this._parents);
    }
  
    function EnterNode(parent, datum) {
      this.ownerDocument = parent.ownerDocument;
      this.namespaceURI = parent.namespaceURI;
      this._next = null;
      this._parent = parent;
      this.__data__ = datum;
    }
  
    EnterNode.prototype = {
      constructor: EnterNode,
      appendChild: function(child) { return this._parent.insertBefore(child, this._next); },
      insertBefore: function(child, next) { return this._parent.insertBefore(child, next); },
      querySelector: function(selector) { return this._parent.querySelector(selector); },
      querySelectorAll: function(selector) { return this._parent.querySelectorAll(selector); }
    };
  
    function constant$4(x) {
      return function() {
        return x;
      };
    }
  
    var keyPrefix = "$"; // Protect against keys like “__proto__”.
  
    function bindIndex(parent, group, enter, update, exit, data) {
      var i = 0,
          node,
          groupLength = group.length,
          dataLength = data.length;
  
      // Put any non-null nodes that fit into update.
      // Put any null nodes into enter.
      // Put any remaining data into enter.
      for (; i < dataLength; ++i) {
        if (node = group[i]) {
          node.__data__ = data[i];
          update[i] = node;
        } else {
          enter[i] = new EnterNode(parent, data[i]);
        }
      }
  
      // Put any non-null nodes that don’t fit into exit.
      for (; i < groupLength; ++i) {
        if (node = group[i]) {
          exit[i] = node;
        }
      }
    }
  
    function bindKey(parent, group, enter, update, exit, data, key) {
      var i,
          node,
          nodeByKeyValue = {},
          groupLength = group.length,
          dataLength = data.length,
          keyValues = new Array(groupLength),
          keyValue;
  
      // Compute the key for each node.
      // If multiple nodes have the same key, the duplicates are added to exit.
      for (i = 0; i < groupLength; ++i) {
        if (node = group[i]) {
          keyValues[i] = keyValue = keyPrefix + key.call(node, node.__data__, i, group);
          if (keyValue in nodeByKeyValue) {
            exit[i] = node;
          } else {
            nodeByKeyValue[keyValue] = node;
          }
        }
      }
  
      // Compute the key for each datum.
      // If there a node associated with this key, join and add it to update.
      // If there is not (or the key is a duplicate), add it to enter.
      for (i = 0; i < dataLength; ++i) {
        keyValue = keyPrefix + key.call(parent, data[i], i, data);
        if (node = nodeByKeyValue[keyValue]) {
          update[i] = node;
          node.__data__ = data[i];
          nodeByKeyValue[keyValue] = null;
        } else {
          enter[i] = new EnterNode(parent, data[i]);
        }
      }
  
      // Add any remaining nodes that were not bound to data to exit.
      for (i = 0; i < groupLength; ++i) {
        if ((node = group[i]) && (nodeByKeyValue[keyValues[i]] === node)) {
          exit[i] = node;
        }
      }
    }
  
    function selection_data(value, key) {
      if (!value) {
        data = new Array(this.size()), j = -1;
        this.each(function(d) { data[++j] = d; });
        return data;
      }
  
      var bind = key ? bindKey : bindIndex,
          parents = this._parents,
          groups = this._groups;
  
      if (typeof value !== "function") value = constant$4(value);
  
      for (var m = groups.length, update = new Array(m), enter = new Array(m), exit = new Array(m), j = 0; j < m; ++j) {
        var parent = parents[j],
            group = groups[j],
            groupLength = group.length,
            data = value.call(parent, parent && parent.__data__, j, parents),
            dataLength = data.length,
            enterGroup = enter[j] = new Array(dataLength),
            updateGroup = update[j] = new Array(dataLength),
            exitGroup = exit[j] = new Array(groupLength);
  
        bind(parent, group, enterGroup, updateGroup, exitGroup, data, key);
  
        // Now connect the enter nodes to their following update node, such that
        // appendChild can insert the materialized enter node before this node,
        // rather than at the end of the parent node.
        for (var i0 = 0, i1 = 0, previous, next; i0 < dataLength; ++i0) {
          if (previous = enterGroup[i0]) {
            if (i0 >= i1) i1 = i0 + 1;
            while (!(next = updateGroup[i1]) && ++i1 < dataLength);
            previous._next = next || null;
          }
        }
      }
  
      update = new Selection(update, parents);
      update._enter = enter;
      update._exit = exit;
      return update;
    }
  
    function selection_exit() {
      return new Selection(this._exit || this._groups.map(sparse), this._parents);
    }
  
    function selection_merge(selection) {
  
      for (var groups0 = this._groups, groups1 = selection._groups, m0 = groups0.length, m1 = groups1.length, m = Math.min(m0, m1), merges = new Array(m0), j = 0; j < m; ++j) {
        for (var group0 = groups0[j], group1 = groups1[j], n = group0.length, merge = merges[j] = new Array(n), node, i = 0; i < n; ++i) {
          if (node = group0[i] || group1[i]) {
            merge[i] = node;
          }
        }
      }
  
      for (; j < m0; ++j) {
        merges[j] = groups0[j];
      }
  
      return new Selection(merges, this._parents);
    }
  
    function selection_order() {
  
      for (var groups = this._groups, j = -1, m = groups.length; ++j < m;) {
        for (var group = groups[j], i = group.length - 1, next = group[i], node; --i >= 0;) {
          if (node = group[i]) {
            if (next && next !== node.nextSibling) next.parentNode.insertBefore(node, next);
            next = node;
          }
        }
      }
  
      return this;
    }
  
    function selection_sort(compare) {
      if (!compare) compare = ascending$2;
  
      function compareNode(a, b) {
        return a && b ? compare(a.__data__, b.__data__) : !a - !b;
      }
  
      for (var groups = this._groups, m = groups.length, sortgroups = new Array(m), j = 0; j < m; ++j) {
        for (var group = groups[j], n = group.length, sortgroup = sortgroups[j] = new Array(n), node, i = 0; i < n; ++i) {
          if (node = group[i]) {
            sortgroup[i] = node;
          }
        }
        sortgroup.sort(compareNode);
      }
  
      return new Selection(sortgroups, this._parents).order();
    }
  
    function ascending$2(a, b) {
      return a < b ? -1 : a > b ? 1 : a >= b ? 0 : NaN;
    }
  
    function selection_call() {
      var callback = arguments[0];
      arguments[0] = this;
      callback.apply(null, arguments);
      return this;
    }
  
    function selection_nodes() {
      var nodes = new Array(this.size()), i = -1;
      this.each(function() { nodes[++i] = this; });
      return nodes;
    }
  
    function selection_node() {
  
      for (var groups = this._groups, j = 0, m = groups.length; j < m; ++j) {
        for (var group = groups[j], i = 0, n = group.length; i < n; ++i) {
          var node = group[i];
          if (node) return node;
        }
      }
  
      return null;
    }
  
    function selection_size() {
      var size = 0;
      this.each(function() { ++size; });
      return size;
    }
  
    function selection_empty() {
      return !this.node();
    }
  
    function selection_each(callback) {
  
      for (var groups = this._groups, j = 0, m = groups.length; j < m; ++j) {
        for (var group = groups[j], i = 0, n = group.length, node; i < n; ++i) {
          if (node = group[i]) callback.call(node, node.__data__, i, group);
        }
      }
  
      return this;
    }
  
    function attrRemove(name) {
      return function() {
        this.removeAttribute(name);
      };
    }
  
    function attrRemoveNS(fullname) {
      return function() {
        this.removeAttributeNS(fullname.space, fullname.local);
      };
    }
  
    function attrConstant(name, value) {
      return function() {
        this.setAttribute(name, value);
      };
    }
  
    function attrConstantNS(fullname, value) {
      return function() {
        this.setAttributeNS(fullname.space, fullname.local, value);
      };
    }
  
    function attrFunction(name, value) {
      return function() {
        var v = value.apply(this, arguments);
        if (v == null) this.removeAttribute(name);
        else this.setAttribute(name, v);
      };
    }
  
    function attrFunctionNS(fullname, value) {
      return function() {
        var v = value.apply(this, arguments);
        if (v == null) this.removeAttributeNS(fullname.space, fullname.local);
        else this.setAttributeNS(fullname.space, fullname.local, v);
      };
    }
  
    function selection_attr(name, value) {
      var fullname = namespace(name);
  
      if (arguments.length < 2) {
        var node = this.node();
        return fullname.local
            ? node.getAttributeNS(fullname.space, fullname.local)
            : node.getAttribute(fullname);
      }
  
      return this.each((value == null
          ? (fullname.local ? attrRemoveNS : attrRemove) : (typeof value === "function"
          ? (fullname.local ? attrFunctionNS : attrFunction)
          : (fullname.local ? attrConstantNS : attrConstant)))(fullname, value));
    }
  
    function window$1(node) {
      return (node.ownerDocument && node.ownerDocument.defaultView) // node is a Node
          || (node.document && node) // node is a Window
          || node.defaultView; // node is a Document
    }
  
    function styleRemove(name) {
      return function() {
        this.style.removeProperty(name);
      };
    }
  
    function styleConstant(name, value, priority) {
      return function() {
        this.style.setProperty(name, value, priority);
      };
    }
  
    function styleFunction(name, value, priority) {
      return function() {
        var v = value.apply(this, arguments);
        if (v == null) this.style.removeProperty(name);
        else this.style.setProperty(name, v, priority);
      };
    }
  
    function selection_style(name, value, priority) {
      var node;
      return arguments.length > 1
          ? this.each((value == null
                ? styleRemove : typeof value === "function"
                ? styleFunction
                : styleConstant)(name, value, priority == null ? "" : priority))
          : window$1(node = this.node())
              .getComputedStyle(node, null)
              .getPropertyValue(name);
    }
  
    function propertyRemove(name) {
      return function() {
        delete this[name];
      };
    }
  
    function propertyConstant(name, value) {
      return function() {
        this[name] = value;
      };
    }
  
    function propertyFunction(name, value) {
      return function() {
        var v = value.apply(this, arguments);
        if (v == null) delete this[name];
        else this[name] = v;
      };
    }
  
    function selection_property(name, value) {
      return arguments.length > 1
          ? this.each((value == null
              ? propertyRemove : typeof value === "function"
              ? propertyFunction
              : propertyConstant)(name, value))
          : this.node()[name];
    }
  
    function classArray(string) {
      return string.trim().split(/^|\s+/);
    }
  
    function classList(node) {
      return node.classList || new ClassList(node);
    }
  
    function ClassList(node) {
      this._node = node;
      this._names = classArray(node.getAttribute("class") || "");
    }
  
    ClassList.prototype = {
      add: function(name) {
        var i = this._names.indexOf(name);
        if (i < 0) {
          this._names.push(name);
          this._node.setAttribute("class", this._names.join(" "));
        }
      },
      remove: function(name) {
        var i = this._names.indexOf(name);
        if (i >= 0) {
          this._names.splice(i, 1);
          this._node.setAttribute("class", this._names.join(" "));
        }
      },
      contains: function(name) {
        return this._names.indexOf(name) >= 0;
      }
    };
  
    function classedAdd(node, names) {
      var list = classList(node), i = -1, n = names.length;
      while (++i < n) list.add(names[i]);
    }
  
    function classedRemove(node, names) {
      var list = classList(node), i = -1, n = names.length;
      while (++i < n) list.remove(names[i]);
    }
  
    function classedTrue(names) {
      return function() {
        classedAdd(this, names);
      };
    }
  
    function classedFalse(names) {
      return function() {
        classedRemove(this, names);
      };
    }
  
    function classedFunction(names, value) {
      return function() {
        (value.apply(this, arguments) ? classedAdd : classedRemove)(this, names);
      };
    }
  
    function selection_classed(name, value) {
      var names = classArray(name + "");
  
      if (arguments.length < 2) {
        var list = classList(this.node()), i = -1, n = names.length;
        while (++i < n) if (!list.contains(names[i])) return false;
        return true;
      }
  
      return this.each((typeof value === "function"
          ? classedFunction : value
          ? classedTrue
          : classedFalse)(names, value));
    }
  
    function textRemove() {
      this.textContent = "";
    }
  
    function textConstant(value) {
      return function() {
        this.textContent = value;
      };
    }
  
    function textFunction(value) {
      return function() {
        var v = value.apply(this, arguments);
        this.textContent = v == null ? "" : v;
      };
    }
  
    function selection_text(value) {
      return arguments.length
          ? this.each(value == null
              ? textRemove : (typeof value === "function"
              ? textFunction
              : textConstant)(value))
          : this.node().textContent;
    }
  
    function htmlRemove() {
      this.innerHTML = "";
    }
  
    function htmlConstant(value) {
      return function() {
        this.innerHTML = value;
      };
    }
  
    function htmlFunction(value) {
      return function() {
        var v = value.apply(this, arguments);
        this.innerHTML = v == null ? "" : v;
      };
    }
  
    function selection_html(value) {
      return arguments.length
          ? this.each(value == null
              ? htmlRemove : (typeof value === "function"
              ? htmlFunction
              : htmlConstant)(value))
          : this.node().innerHTML;
    }
  
    function raise$1() {
      if (this.nextSibling) this.parentNode.appendChild(this);
    }
  
    function selection_raise() {
      return this.each(raise$1);
    }
  
    function lower() {
      if (this.previousSibling) this.parentNode.insertBefore(this, this.parentNode.firstChild);
    }
  
    function selection_lower() {
      return this.each(lower);
    }
  
    function selection_append(name) {
      var create = typeof name === "function" ? name : creator(name);
      return this.select(function() {
        return this.appendChild(create.apply(this, arguments));
      });
    }
  
    function constantNull() {
      return null;
    }
  
    function selection_insert(name, before) {
      var create = typeof name === "function" ? name : creator(name),
          select = before == null ? constantNull : typeof before === "function" ? before : selector(before);
      return this.select(function() {
        return this.insertBefore(create.apply(this, arguments), select.apply(this, arguments) || null);
      });
    }
  
    function remove() {
      var parent = this.parentNode;
      if (parent) parent.removeChild(this);
    }
  
    function selection_remove() {
      return this.each(remove);
    }
  
    function selection_datum(value) {
      return arguments.length
          ? this.property("__data__", value)
          : this.node().__data__;
    }
  
    function dispatchEvent(node, type, params) {
      var window = window$1(node),
          event = window.CustomEvent;
  
      if (event) {
        event = new event(type, params);
      } else {
        event = window.document.createEvent("Event");
        if (params) event.initEvent(type, params.bubbles, params.cancelable), event.detail = params.detail;
        else event.initEvent(type, false, false);
      }
  
      node.dispatchEvent(event);
    }
  
    function dispatchConstant(type, params) {
      return function() {
        return dispatchEvent(this, type, params);
      };
    }
  
    function dispatchFunction(type, params) {
      return function() {
        return dispatchEvent(this, type, params.apply(this, arguments));
      };
    }
  
    function selection_dispatch(type, params) {
      return this.each((typeof params === "function"
          ? dispatchFunction
          : dispatchConstant)(type, params));
    }
  
    var root = [null];
  
    function Selection(groups, parents) {
      this._groups = groups;
      this._parents = parents;
    }
  
    function selection() {
      return new Selection([[document.documentElement]], root);
    }
  
    Selection.prototype = selection.prototype = {
      constructor: Selection,
      select: selection_select,
      selectAll: selection_selectAll,
      filter: selection_filter,
      data: selection_data,
      enter: selection_enter,
      exit: selection_exit,
      merge: selection_merge,
      order: selection_order,
      sort: selection_sort,
      call: selection_call,
      nodes: selection_nodes,
      node: selection_node,
      size: selection_size,
      empty: selection_empty,
      each: selection_each,
      attr: selection_attr,
      style: selection_style,
      property: selection_property,
      classed: selection_classed,
      text: selection_text,
      html: selection_html,
      raise: selection_raise,
      lower: selection_lower,
      append: selection_append,
      insert: selection_insert,
      remove: selection_remove,
      datum: selection_datum,
      on: selection_on,
      dispatch: selection_dispatch
    };
  
    function select(selector) {
      return typeof selector === "string"
          ? new Selection([[document.querySelector(selector)]], [document.documentElement])
          : new Selection([[selector]], root);
    }
  
    function selectAll(selector) {
      return typeof selector === "string"
          ? new Selection([document.querySelectorAll(selector)], [document.documentElement])
          : new Selection([selector == null ? [] : selector], root);
    }
  
    function touch(node, touches, identifier) {
      if (arguments.length < 3) identifier = touches, touches = sourceEvent().changedTouches;
  
      for (var i = 0, n = touches ? touches.length : 0, touch; i < n; ++i) {
        if ((touch = touches[i]).identifier === identifier) {
          return point$5(node, touch);
        }
      }
  
      return null;
    }
  
    function touches(node, touches) {
      if (touches == null) touches = sourceEvent().touches;
  
      for (var i = 0, n = touches ? touches.length : 0, points = new Array(n); i < n; ++i) {
        points[i] = point$5(node, touches[i]);
      }
  
      return points;
    }
  
    var emptyOn = dispatch("start", "end", "interrupt");
    var emptyTween = [];
  
    var CREATED = 0;
    var SCHEDULED = 1;
    var STARTING = 2;
    var STARTED = 3;
    var ENDING = 4;
    var ENDED = 5;
  
    function schedule(node, name, id, index, group, timing) {
      var schedules = node.__transition;
      if (!schedules) node.__transition = {};
      else if (id in schedules) return;
      create(node, id, {
        name: name,
        index: index, // For context during callback.
        group: group, // For context during callback.
        on: emptyOn,
        tween: emptyTween,
        time: timing.time,
        delay: timing.delay,
        duration: timing.duration,
        ease: timing.ease,
        timer: null,
        state: CREATED
      });
    }
  
    function init(node, id) {
      var schedule = node.__transition;
      if (!schedule || !(schedule = schedule[id]) || schedule.state > CREATED) throw new Error("too late");
      return schedule;
    }
  
    function set$2(node, id) {
      var schedule = node.__transition;
      if (!schedule || !(schedule = schedule[id]) || schedule.state > STARTING) throw new Error("too late");
      return schedule;
    }
  
    function get$1(node, id) {
      var schedule = node.__transition;
      if (!schedule || !(schedule = schedule[id])) throw new Error("too late");
      return schedule;
    }
  
    function create(node, id, self) {
      var schedules = node.__transition,
          tween;
  
      // Initialize the self timer when the transition is created.
      // Note the actual delay is not known until the first callback!
      schedules[id] = self;
      self.timer = timer(schedule, 0, self.time);
  
      // If the delay is greater than this first sleep, sleep some more;
      // otherwise, start immediately.
      function schedule(elapsed) {
        self.state = SCHEDULED;
        if (self.delay <= elapsed) start(elapsed - self.delay);
        else self.timer.restart(start, self.delay, self.time);
      }
  
      function start(elapsed) {
        var i, j, n, o;
  
        for (i in schedules) {
          o = schedules[i];
          if (o.name !== self.name) continue;
  
          // Interrupt the active transition, if any.
          // Dispatch the interrupt event.
          if (o.state === STARTED) {
            o.state = ENDED;
            o.timer.stop();
            o.on.call("interrupt", node, node.__data__, o.index, o.group);
            delete schedules[i];
          }
  
          // Cancel any pre-empted transitions. No interrupt event is dispatched
          // because the cancelled transitions never started. Note that this also
          // removes this transition from the pending list!
          else if (+i < id) {
            o.state = ENDED;
            o.timer.stop();
            delete schedules[i];
          }
        }
  
        // Defer the first tick to end of the current frame; see mbostock/d3#1576.
        // Note the transition may be canceled after start and before the first tick!
        // Note this must be scheduled before the start event; see d3/d3-transition#16!
        // Assuming this is successful, subsequent callbacks go straight to tick.
        timeout$1(function() {
          if (self.state === STARTED) {
            self.timer.restart(tick, self.delay, self.time);
            tick(elapsed);
          }
        });
  
        // Dispatch the start event.
        // Note this must be done before the tween are initialized.
        self.state = STARTING;
        self.on.call("start", node, node.__data__, self.index, self.group);
        if (self.state !== STARTING) return; // interrupted
        self.state = STARTED;
  
        // Initialize the tween, deleting null tween.
        tween = new Array(n = self.tween.length);
        for (i = 0, j = -1; i < n; ++i) {
          if (o = self.tween[i].value.call(node, node.__data__, self.index, self.group)) {
            tween[++j] = o;
          }
        }
        tween.length = j + 1;
      }
  
      function tick(elapsed) {
        var t = elapsed < self.duration ? self.ease.call(null, elapsed / self.duration) : (self.state = ENDING, 1),
            i = -1,
            n = tween.length;
  
        while (++i < n) {
          tween[i].call(null, t);
        }
  
        // Dispatch the end event.
        if (self.state === ENDING) {
          self.state = ENDED;
          self.timer.stop();
          self.on.call("end", node, node.__data__, self.index, self.group);
          for (i in schedules) if (+i !== id) return void delete schedules[id];
          delete node.__transition;
        }
      }
    }
  
    function interrupt(node, name) {
      var schedules = node.__transition,
          schedule,
          active,
          empty = true,
          i;
  
      if (!schedules) return;
  
      name = name == null ? null : name + "";
  
      for (i in schedules) {
        if ((schedule = schedules[i]).name !== name) { empty = false; continue; }
        active = schedule.state === STARTED;
        schedule.state = ENDED;
        schedule.timer.stop();
        if (active) schedule.on.call("interrupt", node, node.__data__, schedule.index, schedule.group);
        delete schedules[i];
      }
  
      if (empty) delete node.__transition;
    }
  
    function selection_interrupt(name) {
      return this.each(function() {
        interrupt(this, name);
      });
    }
  
    function tweenRemove(id, name) {
      var tween0, tween1;
      return function() {
        var schedule = set$2(this, id),
            tween = schedule.tween;
  
        // If this node shared tween with the previous node,
        // just assign the updated shared tween and we’re done!
        // Otherwise, copy-on-write.
        if (tween !== tween0) {
          tween1 = tween0 = tween;
          for (var i = 0, n = tween1.length; i < n; ++i) {
            if (tween1[i].name === name) {
              tween1 = tween1.slice();
              tween1.splice(i, 1);
              break;
            }
          }
        }
  
        schedule.tween = tween1;
      };
    }
  
    function tweenFunction(id, name, value) {
      var tween0, tween1;
      if (typeof value !== "function") throw new Error;
      return function() {
        var schedule = set$2(this, id),
            tween = schedule.tween;
  
        // If this node shared tween with the previous node,
        // just assign the updated shared tween and we’re done!
        // Otherwise, copy-on-write.
        if (tween !== tween0) {
          tween1 = (tween0 = tween).slice();
          for (var t = {name: name, value: value}, i = 0, n = tween1.length; i < n; ++i) {
            if (tween1[i].name === name) {
              tween1[i] = t;
              break;
            }
          }
          if (i === n) tween1.push(t);
        }
  
        schedule.tween = tween1;
      };
    }
  
    function transition_tween(name, value) {
      var id = this._id;
  
      name += "";
  
      if (arguments.length < 2) {
        var tween = get$1(this.node(), id).tween;
        for (var i = 0, n = tween.length, t; i < n; ++i) {
          if ((t = tween[i]).name === name) {
            return t.value;
          }
        }
        return null;
      }
  
      return this.each((value == null ? tweenRemove : tweenFunction)(id, name, value));
    }
  
    function tweenValue(transition, name, value) {
      var id = transition._id;
  
      transition.each(function() {
        var schedule = set$2(this, id);
        (schedule.value || (schedule.value = {}))[name] = value.apply(this, arguments);
      });
  
      return function(node) {
        return get$1(node, id).value[name];
      };
    }
  
    function interpolate$1(a, b) {
      var c;
      return (typeof b === "number" ? interpolateNumber
          : b instanceof color ? interpolateRgb
          : (c = color(b)) ? (b = c, interpolateRgb)
          : interpolateString)(a, b);
    }
  
    function attrRemove$1(name) {
      return function() {
        this.removeAttribute(name);
      };
    }
  
    function attrRemoveNS$1(fullname) {
      return function() {
        this.removeAttributeNS(fullname.space, fullname.local);
      };
    }
  
    function attrConstant$1(name, interpolate, value1) {
      var value00,
          interpolate0;
      return function() {
        var value0 = this.getAttribute(name);
        return value0 === value1 ? null
            : value0 === value00 ? interpolate0
            : interpolate0 = interpolate(value00 = value0, value1);
      };
    }
  
    function attrConstantNS$1(fullname, interpolate, value1) {
      var value00,
          interpolate0;
      return function() {
        var value0 = this.getAttributeNS(fullname.space, fullname.local);
        return value0 === value1 ? null
            : value0 === value00 ? interpolate0
            : interpolate0 = interpolate(value00 = value0, value1);
      };
    }
  
    function attrFunction$1(name, interpolate, value) {
      var value00,
          value10,
          interpolate0;
      return function() {
        var value0, value1 = value(this);
        if (value1 == null) return void this.removeAttribute(name);
        value0 = this.getAttribute(name);
        return value0 === value1 ? null
            : value0 === value00 && value1 === value10 ? interpolate0
            : interpolate0 = interpolate(value00 = value0, value10 = value1);
      };
    }
  
    function attrFunctionNS$1(fullname, interpolate, value) {
      var value00,
          value10,
          interpolate0;
      return function() {
        var value0, value1 = value(this);
        if (value1 == null) return void this.removeAttributeNS(fullname.space, fullname.local);
        value0 = this.getAttributeNS(fullname.space, fullname.local);
        return value0 === value1 ? null
            : value0 === value00 && value1 === value10 ? interpolate0
            : interpolate0 = interpolate(value00 = value0, value10 = value1);
      };
    }
  
    function transition_attr(name, value) {
      var fullname = namespace(name), i = fullname === "transform" ? interpolateTransform$2 : interpolate$1;
      return this.attrTween(name, typeof value === "function"
          ? (fullname.local ? attrFunctionNS$1 : attrFunction$1)(fullname, i, tweenValue(this, "attr." + name, value))
          : value == null ? (fullname.local ? attrRemoveNS$1 : attrRemove$1)(fullname)
          : (fullname.local ? attrConstantNS$1 : attrConstant$1)(fullname, i, value));
    }
  
    function attrTweenNS(fullname, value) {
      function tween() {
        var node = this, i = value.apply(node, arguments);
        return i && function(t) {
          node.setAttributeNS(fullname.space, fullname.local, i(t));
        };
      }
      tween._value = value;
      return tween;
    }
  
    function attrTween(name, value) {
      function tween() {
        var node = this, i = value.apply(node, arguments);
        return i && function(t) {
          node.setAttribute(name, i(t));
        };
      }
      tween._value = value;
      return tween;
    }
  
    function transition_attrTween(name, value) {
      var key = "attr." + name;
      if (arguments.length < 2) return (key = this.tween(key)) && key._value;
      if (value == null) return this.tween(key, null);
      if (typeof value !== "function") throw new Error;
      var fullname = namespace(name);
      return this.tween(key, (fullname.local ? attrTweenNS : attrTween)(fullname, value));
    }
  
    function delayFunction(id, value) {
      return function() {
        init(this, id).delay = +value.apply(this, arguments);
      };
    }
  
    function delayConstant(id, value) {
      return value = +value, function() {
        init(this, id).delay = value;
      };
    }
  
    function transition_delay(value) {
      var id = this._id;
  
      return arguments.length
          ? this.each((typeof value === "function"
              ? delayFunction
              : delayConstant)(id, value))
          : get$1(this.node(), id).delay;
    }
  
    function durationFunction(id, value) {
      return function() {
        set$2(this, id).duration = +value.apply(this, arguments);
      };
    }
  
    function durationConstant(id, value) {
      return value = +value, function() {
        set$2(this, id).duration = value;
      };
    }
  
    function transition_duration(value) {
      var id = this._id;
  
      return arguments.length
          ? this.each((typeof value === "function"
              ? durationFunction
              : durationConstant)(id, value))
          : get$1(this.node(), id).duration;
    }
  
    function easeConstant(id, value) {
      if (typeof value !== "function") throw new Error;
      return function() {
        set$2(this, id).ease = value;
      };
    }
  
    function transition_ease(value) {
      var id = this._id;
  
      return arguments.length
          ? this.each(easeConstant(id, value))
          : get$1(this.node(), id).ease;
    }
  
    function transition_filter(match) {
      if (typeof match !== "function") match = matcher$1(match);
  
      for (var groups = this._groups, m = groups.length, subgroups = new Array(m), j = 0; j < m; ++j) {
        for (var group = groups[j], n = group.length, subgroup = subgroups[j] = [], node, i = 0; i < n; ++i) {
          if ((node = group[i]) && match.call(node, node.__data__, i, group)) {
            subgroup.push(node);
          }
        }
      }
  
      return new Transition(subgroups, this._parents, this._name, this._id);
    }
  
    function transition_merge(transition) {
      if (transition._id !== this._id) throw new Error;
  
      for (var groups0 = this._groups, groups1 = transition._groups, m0 = groups0.length, m1 = groups1.length, m = Math.min(m0, m1), merges = new Array(m0), j = 0; j < m; ++j) {
        for (var group0 = groups0[j], group1 = groups1[j], n = group0.length, merge = merges[j] = new Array(n), node, i = 0; i < n; ++i) {
          if (node = group0[i] || group1[i]) {
            merge[i] = node;
          }
        }
      }
  
      for (; j < m0; ++j) {
        merges[j] = groups0[j];
      }
  
      return new Transition(merges, this._parents, this._name, this._id);
    }
  
    function start$1(name) {
      return (name + "").trim().split(/^|\s+/).every(function(t) {
        var i = t.indexOf(".");
        if (i >= 0) t = t.slice(0, i);
        return !t || t === "start";
      });
    }
  
    function onFunction(id, name, listener) {
      var on0, on1, sit = start$1(name) ? init : set$2;
      return function() {
        var schedule = sit(this, id),
            on = schedule.on;
  
        // If this node shared a dispatch with the previous node,
        // just assign the updated shared dispatch and we’re done!
        // Otherwise, copy-on-write.
        if (on !== on0) (on1 = (on0 = on).copy()).on(name, listener);
  
        schedule.on = on1;
      };
    }
  
    function transition_on(name, listener) {
      var id = this._id;
  
      return arguments.length < 2
          ? get$1(this.node(), id).on.on(name)
          : this.each(onFunction(id, name, listener));
    }
  
    function removeFunction(id) {
      return function() {
        var parent = this.parentNode;
        for (var i in this.__transition) if (+i !== id) return;
        if (parent) parent.removeChild(this);
      };
    }
  
    function transition_remove() {
      return this.on("end.remove", removeFunction(this._id));
    }
  
    function transition_select(select) {
      var name = this._name,
          id = this._id;
  
      if (typeof select !== "function") select = selector(select);
  
      for (var groups = this._groups, m = groups.length, subgroups = new Array(m), j = 0; j < m; ++j) {
        for (var group = groups[j], n = group.length, subgroup = subgroups[j] = new Array(n), node, subnode, i = 0; i < n; ++i) {
          if ((node = group[i]) && (subnode = select.call(node, node.__data__, i, group))) {
            if ("__data__" in node) subnode.__data__ = node.__data__;
            subgroup[i] = subnode;
            schedule(subgroup[i], name, id, i, subgroup, get$1(node, id));
          }
        }
      }
  
      return new Transition(subgroups, this._parents, name, id);
    }
  
    function transition_selectAll(select) {
      var name = this._name,
          id = this._id;
  
      if (typeof select !== "function") select = selectorAll(select);
  
      for (var groups = this._groups, m = groups.length, subgroups = [], parents = [], j = 0; j < m; ++j) {
        for (var group = groups[j], n = group.length, node, i = 0; i < n; ++i) {
          if (node = group[i]) {
            for (var children = select.call(node, node.__data__, i, group), child, inherit = get$1(node, id), k = 0, l = children.length; k < l; ++k) {
              if (child = children[k]) {
                schedule(child, name, id, k, children, inherit);
              }
            }
            subgroups.push(children);
            parents.push(node);
          }
        }
      }
  
      return new Transition(subgroups, parents, name, id);
    }
  
    var Selection$1 = selection.prototype.constructor;
  
    function transition_selection() {
      return new Selection$1(this._groups, this._parents);
    }
  
    function styleRemove$1(name, interpolate) {
      var value00,
          value10,
          interpolate0;
      return function() {
        var style = window$1(this).getComputedStyle(this, null),
            value0 = style.getPropertyValue(name),
            value1 = (this.style.removeProperty(name), style.getPropertyValue(name));
        return value0 === value1 ? null
            : value0 === value00 && value1 === value10 ? interpolate0
            : interpolate0 = interpolate(value00 = value0, value10 = value1);
      };
    }
  
    function styleRemoveEnd(name) {
      return function() {
        this.style.removeProperty(name);
      };
    }
  
    function styleConstant$1(name, interpolate, value1) {
      var value00,
          interpolate0;
      return function() {
        var value0 = window$1(this).getComputedStyle(this, null).getPropertyValue(name);
        return value0 === value1 ? null
            : value0 === value00 ? interpolate0
            : interpolate0 = interpolate(value00 = value0, value1);
      };
    }
  
    function styleFunction$1(name, interpolate, value) {
      var value00,
          value10,
          interpolate0;
      return function() {
        var style = window$1(this).getComputedStyle(this, null),
            value0 = style.getPropertyValue(name),
            value1 = value(this);
        if (value1 == null) value1 = (this.style.removeProperty(name), style.getPropertyValue(name));
        return value0 === value1 ? null
            : value0 === value00 && value1 === value10 ? interpolate0
            : interpolate0 = interpolate(value00 = value0, value10 = value1);
      };
    }
  
    function transition_style(name, value, priority) {
      var i = (name += "") === "transform" ? interpolateTransform$1 : interpolate$1;
      return value == null ? this
              .styleTween(name, styleRemove$1(name, i))
              .on("end.style." + name, styleRemoveEnd(name))
          : this.styleTween(name, typeof value === "function"
              ? styleFunction$1(name, i, tweenValue(this, "style." + name, value))
              : styleConstant$1(name, i, value), priority);
    }
  
    function styleTween(name, value, priority) {
      function tween() {
        var node = this, i = value.apply(node, arguments);
        return i && function(t) {
          node.style.setProperty(name, i(t), priority);
        };
      }
      tween._value = value;
      return tween;
    }
  
    function transition_styleTween(name, value, priority) {
      var key = "style." + (name += "");
      if (arguments.length < 2) return (key = this.tween(key)) && key._value;
      if (value == null) return this.tween(key, null);
      if (typeof value !== "function") throw new Error;
      return this.tween(key, styleTween(name, value, priority == null ? "" : priority));
    }
  
    function textConstant$1(value) {
      return function() {
        this.textContent = value;
      };
    }
  
    function textFunction$1(value) {
      return function() {
        var value1 = value(this);
        this.textContent = value1 == null ? "" : value1;
      };
    }
  
    function transition_text(value) {
      return this.tween("text", typeof value === "function"
          ? textFunction$1(tweenValue(this, "text", value))
          : textConstant$1(value == null ? "" : value + ""));
    }
  
    function transition_transition() {
      var name = this._name,
          id0 = this._id,
          id1 = newId();
  
      for (var groups = this._groups, m = groups.length, j = 0; j < m; ++j) {
        for (var group = groups[j], n = group.length, node, i = 0; i < n; ++i) {
          if (node = group[i]) {
            var inherit = get$1(node, id0);
            schedule(node, name, id1, i, group, {
              time: inherit.time + inherit.delay + inherit.duration,
              delay: 0,
              duration: inherit.duration,
              ease: inherit.ease
            });
          }
        }
      }
  
      return new Transition(groups, this._parents, name, id1);
    }
  
    var id = 0;
  
    function Transition(groups, parents, name, id) {
      this._groups = groups;
      this._parents = parents;
      this._name = name;
      this._id = id;
    }
  
    function transition(name) {
      return selection().transition(name);
    }
  
    function newId() {
      return ++id;
    }
  
    var selection_prototype = selection.prototype;
  
    Transition.prototype = transition.prototype = {
      constructor: Transition,
      select: transition_select,
      selectAll: transition_selectAll,
      filter: transition_filter,
      merge: transition_merge,
      selection: transition_selection,
      transition: transition_transition,
      call: selection_prototype.call,
      nodes: selection_prototype.nodes,
      node: selection_prototype.node,
      size: selection_prototype.size,
      empty: selection_prototype.empty,
      each: selection_prototype.each,
      on: transition_on,
      attr: transition_attr,
      attrTween: transition_attrTween,
      style: transition_style,
      styleTween: transition_styleTween,
      text: transition_text,
      remove: transition_remove,
      tween: transition_tween,
      delay: transition_delay,
      duration: transition_duration,
      ease: transition_ease
    };
  
    var defaultTiming = {
      time: null, // Set on use.
      delay: 0,
      duration: 250,
      ease: easeCubicInOut
    };
  
    function inherit(node, id) {
      var timing;
      while (!(timing = node.__transition) || !(timing = timing[id])) {
        if (!(node = node.parentNode)) {
          return defaultTiming.time = now(), defaultTiming;
        }
      }
      return timing;
    }
  
    function selection_transition(name) {
      var id,
          timing;
  
      if (name instanceof Transition) {
        id = name._id, name = name._name;
      } else {
        id = newId(), (timing = defaultTiming).time = now(), name = name == null ? null : name + "";
      }
  
      for (var groups = this._groups, m = groups.length, j = 0; j < m; ++j) {
        for (var group = groups[j], n = group.length, node, i = 0; i < n; ++i) {
          if (node = group[i]) {
            schedule(node, name, id, i, group, timing || inherit(node, id));
          }
        }
      }
  
      return new Transition(groups, this._parents, name, id);
    }
  
    selection.prototype.interrupt = selection_interrupt;
    selection.prototype.transition = selection_transition;
  
    var root$1 = [null];
  
    function active(node, name) {
      var schedules = node.__transition,
          schedule,
          i;
  
      if (schedules) {
        name = name == null ? null : name + "";
        for (i in schedules) {
          if ((schedule = schedules[i]).state > SCHEDULED && schedule.name === name) {
            return new Transition([[node]], root$1, name, +i);
          }
        }
      }
  
      return null;
    }
  
    var slice$4 = Array.prototype.slice;
  
    function identity$5(x) {
      return x;
    }
  
    var top = 1;
    var right = 2;
    var bottom = 3;
    var left = 4;
  var   epsilon$2 = 1e-6;
    function translateX(scale0, scale1, d) {
      var x = scale0(d);
      return "translate(" + (isFinite(x) ? x : scale1(d)) + ",0)";
    }
  
    function translateY(scale0, scale1, d) {
      var y = scale0(d);
      return "translate(0," + (isFinite(y) ? y : scale1(d)) + ")";
    }
  
    function center(scale) {
      var offset = scale.bandwidth() / 2;
      if (scale.round()) offset = Math.round(offset);
      return function(d) {
        return scale(d) + offset;
      };
    }
  
    function entering() {
      return !this.__axis;
    }
  
    function axis(orient, scale) {
      var tickArguments = [],
          tickValues = null,
          tickFormat = null,
          tickSizeInner = 6,
          tickSizeOuter = 6,
          tickPadding = 3;
  
      function axis(context) {
        var values = tickValues == null ? (scale.ticks ? scale.ticks.apply(scale, tickArguments) : scale.domain()) : tickValues,
            format = tickFormat == null ? (scale.tickFormat ? scale.tickFormat.apply(scale, tickArguments) : identity$5) : tickFormat,
            spacing = Math.max(tickSizeInner, 0) + tickPadding,
            transform = orient === top || orient === bottom ? translateX : translateY,
            range = scale.range(),
            range0 = range[0] + 0.5,
            range1 = range[range.length - 1] + 0.5,
            position = (scale.bandwidth ? center : identity$5)(scale.copy()),
            selection = context.selection ? context.selection() : context,
            path = selection.selectAll(".domain").data([null]),
            tick = selection.selectAll(".tick").data(values, scale).order(),
            tickExit = tick.exit(),
            tickEnter = tick.enter().append("g").attr("class", "tick"),
            line = tick.select("line"),
            text = tick.select("text"),
            k = orient === top || orient === left ? -1 : 1,
            x, y = orient === left || orient === right ? (x = "x", "y") : (x = "y", "x");
  
        path = path.merge(path.enter().insert("path", ".tick")
            .attr("class", "domain")
            .attr("stroke", "#000"));
  
        tick = tick.merge(tickEnter);
  
        line = line.merge(tickEnter.append("line")
            .attr("stroke", "#000")
            .attr(x + "2", k * tickSizeInner)
            .attr(y + "1", 0.5)
            .attr(y + "2", 0.5));
  
        text = text.merge(tickEnter.append("text")
            .attr("fill", "#000")
            .attr(x, k * spacing)
            .attr(y, 0.5)
            .attr("dy", orient === top ? "0em" : orient === bottom ? "0.71em" : "0.32em"));
  
        if (context !== selection) {
          path = path.transition(context);
          tick = tick.transition(context);
          line = line.transition(context);
          text = text.transition(context);
  
          tickExit = tickExit.transition(context)
              .attr("opacity", epsilon$2)
              .attr("transform", function(d) { return transform(position, this.parentNode.__axis || position, d); });
  
          tickEnter
              .attr("opacity", epsilon$2)
              .attr("transform", function(d) { return transform(this.parentNode.__axis || position, position, d); });
        }
  
        tickExit.remove();
  
        path
            .attr("d", orient === left || orient == right
                ? "M" + k * tickSizeOuter + "," + range0 + "H0.5V" + range1 + "H" + k * tickSizeOuter
                : "M" + range0 + "," + k * tickSizeOuter + "V0.5H" + range1 + "V" + k * tickSizeOuter);
  
        tick
            .attr("opacity", 1)
            .attr("transform", function(d) { return transform(position, position, d); });
  
        line
            .attr(x + "2", k * tickSizeInner);
  
        text
            .attr(x, k * spacing)
            .text(format);
  
        selection.filter(entering)
            .attr("fill", "none")
            .attr("font-size", 10)
            .attr("font-family", "sans-serif")
            .attr("text-anchor", orient === right ? "start" : orient === left ? "end" : "middle");
  
        selection
            .each(function() { this.__axis = position; });
      }
  
      axis.scale = function(_) {
        return arguments.length ? (scale = _, axis) : scale;
      };
  
      axis.ticks = function() {
        return tickArguments = slice$4.call(arguments), axis;
      };
  
      axis.tickArguments = function(_) {
        return arguments.length ? (tickArguments = _ == null ? [] : slice$4.call(_), axis) : tickArguments.slice();
      };
  
      axis.tickValues = function(_) {
        return arguments.length ? (tickValues = _ == null ? null : slice$4.call(_), axis) : tickValues && tickValues.slice();
      };
  
      axis.tickFormat = function(_) {
        return arguments.length ? (tickFormat = _, axis) : tickFormat;
      };
  
      axis.tickSize = function(_) {
        return arguments.length ? (tickSizeInner = tickSizeOuter = +_, axis) : tickSizeInner;
      };
  
      axis.tickSizeInner = function(_) {
        return arguments.length ? (tickSizeInner = +_, axis) : tickSizeInner;
      };
  
      axis.tickSizeOuter = function(_) {
        return arguments.length ? (tickSizeOuter = +_, axis) : tickSizeOuter;
      };
  
      axis.tickPadding = function(_) {
        return arguments.length ? (tickPadding = +_, axis) : tickPadding;
      };
  
      return axis;
    }
  
    function axisTop(scale) {
      return axis(top, scale);
    }
  
    function axisRight(scale) {
      return axis(right, scale);
    }
  
    function axisBottom(scale) {
      return axis(bottom, scale);
    }
  
    function axisLeft(scale) {
      return axis(left, scale);
    }
  
    function defaultSeparation(a, b) {
      return a.parent === b.parent ? 1 : 2;
    }
  
    function meanX(children) {
      return children.reduce(meanXReduce, 0) / children.length;
    }
  
    function meanXReduce(x, c) {
      return x + c.x;
    }
  
    function maxY(children) {
      return 1 + children.reduce(maxYReduce, 0);
    }
  
    function maxYReduce(y, c) {
      return Math.max(y, c.y);
    }
  
    function leafLeft(node) {
      var children;
      while (children = node.children) node = children[0];
      return node;
    }
  
    function leafRight(node) {
      var children;
      while (children = node.children) node = children[children.length - 1];
      return node;
    }
  
    function cluster() {
      var separation = defaultSeparation,
          dx = 1,
          dy = 1,
          nodeSize = false;
  
      function cluster(root) {
        var previousNode,
            x = 0;
  
        // First walk, computing the initial x & y values.
        root.eachAfter(function(node) {
          var children = node.children;
          if (children) {
            node.x = meanX(children);
            node.y = maxY(children);
          } else {
            node.x = previousNode ? x += separation(node, previousNode) : 0;
            node.y = 0;
            previousNode = node;
          }
        });
  
        var left = leafLeft(root),
            right = leafRight(root),
            x0 = left.x - separation(left, right) / 2,
            x1 = right.x + separation(right, left) / 2;
  
        // Second walk, normalizing x & y to the desired size.
        return root.eachAfter(nodeSize ? function(node) {
          node.x = (node.x - root.x) * dx;
          node.y = (root.y - node.y) * dy;
        } : function(node) {
          node.x = (node.x - x0) / (x1 - x0) * dx;
          node.y = (1 - (root.y ? node.y / root.y : 1)) * dy;
        });
      }
  
      cluster.separation = function(x) {
        return arguments.length ? (separation = x, cluster) : separation;
      };
  
      cluster.size = function(x) {
        return arguments.length ? (nodeSize = false, dx = +x[0], dy = +x[1], cluster) : (nodeSize ? null : [dx, dy]);
      };
  
      cluster.nodeSize = function(x) {
        return arguments.length ? (nodeSize = true, dx = +x[0], dy = +x[1], cluster) : (nodeSize ? [dx, dy] : null);
      };
  
      return cluster;
    }
  
    function node_each(callback) {
      var node = this, current, next = [node], children, i, n;
      do {
        current = next.reverse(), next = [];
        while (node = current.pop()) {
          callback(node), children = node.children;
          if (children) for (i = 0, n = children.length; i < n; ++i) {
            next.push(children[i]);
          }
        }
      } while (next.length);
      return this;
    }
  
    function node_eachBefore(callback) {
      var node = this, nodes = [node], children, i;
      while (node = nodes.pop()) {
        callback(node), children = node.children;
        if (children) for (i = children.length - 1; i >= 0; --i) {
          nodes.push(children[i]);
        }
      }
      return this;
    }
  
    function node_eachAfter(callback) {
      var node = this, nodes = [node], next = [], children, i, n;
      while (node = nodes.pop()) {
        next.push(node), children = node.children;
        if (children) for (i = 0, n = children.length; i < n; ++i) {
          nodes.push(children[i]);
        }
      }
      while (node = next.pop()) {
        callback(node);
      }
      return this;
    }
  
    function node_sum(value) {
      return this.eachAfter(function(node) {
        var sum = +value(node.data) || 0,
            children = node.children,
            i = children && children.length;
        while (--i >= 0) sum += children[i].value;
        node.value = sum;
      });
    }
  
    function node_sort(compare) {
      return this.eachBefore(function(node) {
        if (node.children) {
          node.children.sort(compare);
        }
      });
    }
  
    function node_path(end) {
      var start = this,
          ancestor = leastCommonAncestor(start, end),
          nodes = [start];
      while (start !== ancestor) {
        start = start.parent;
        nodes.push(start);
      }
      var k = nodes.length;
      while (end !== ancestor) {
        nodes.splice(k, 0, end);
        end = end.parent;
      }
      return nodes;
    }
  
    function leastCommonAncestor(a, b) {
      if (a === b) return a;
      var aNodes = a.ancestors(),
          bNodes = b.ancestors(),
          c = null;
      a = aNodes.pop();
      b = bNodes.pop();
      while (a === b) {
        c = a;
        a = aNodes.pop();
        b = bNodes.pop();
      }
      return c;
    }
  
    function node_ancestors() {
      var node = this, nodes = [node];
      while (node = node.parent) {
        nodes.push(node);
      }
      return nodes;
    }
  
    function node_descendants() {
      var nodes = [];
      this.each(function(node) {
        nodes.push(node);
      });
      return nodes;
    }
  
    function node_leaves() {
      var leaves = [];
      this.eachBefore(function(node) {
        if (!node.children) {
          leaves.push(node);
        }
      });
      return leaves;
    }
  
    function node_links() {
      var root = this, links = [];
      root.each(function(node) {
        if (node !== root) { // Don’t include the root’s parent, if any.
          links.push({source: node.parent, target: node});
        }
      });
      return links;
    }
  
    function hierarchy(data, children) {
      var root = new Node(data),
          valued = +data.value && (root.value = data.value),
          node,
          nodes = [root],
          child,
          childs,
          i,
          n;
  
      if (children == null) children = defaultChildren;
  
      while (node = nodes.pop()) {
        if (valued) node.value = +node.data.value;
        if ((childs = children(node.data)) && (n = childs.length)) {
          node.children = new Array(n);
          for (i = n - 1; i >= 0; --i) {
            nodes.push(child = node.children[i] = new Node(childs[i]));
            child.parent = node;
            child.depth = node.depth + 1;
          }
        }
      }
  
      return root.eachBefore(computeHeight);
    }
  
    function node_copy() {
      return hierarchy(this).eachBefore(copyData);
    }
  
    function defaultChildren(d) {
      return d.children;
    }
  
    function copyData(node) {
      node.data = node.data.data;
    }
  
    function computeHeight(node) {
      var height = 0;
      do node.height = height;
      while ((node = node.parent) && (node.height < ++height));
    }
  
    function Node(data) {
      this.data = data;
      this.depth =
      this.height = 0;
      this.parent = null;
    }
  
    Node.prototype = hierarchy.prototype = {
      constructor: Node,
      each: node_each,
      eachAfter: node_eachAfter,
      eachBefore: node_eachBefore,
      sum: node_sum,
      sort: node_sort,
      path: node_path,
      ancestors: node_ancestors,
      descendants: node_descendants,
      leaves: node_leaves,
      links: node_links,
      copy: node_copy
    };
  
    function Node$2(value) {
      this._ = value;
      this.next = null;
    }
  
    function shuffle$1(array) {
      var i,
          n = (array = array.slice()).length,
          head = null,
          node = head;
  
      while (n) {
        var next = new Node$2(array[n - 1]);
        if (node) node = node.next = next;
        else node = head = next;
        array[i] = array[--n];
      }
  
      return {
        head: head,
        tail: node
      };
    }
  
    function enclose(circles) {
      return encloseN(shuffle$1(circles), []);
    }
  
    function encloses(a, b) {
      var dx = b.x - a.x,
          dy = b.y - a.y,
          dr = a.r - b.r;
      return dr * dr + 1e-6 > dx * dx + dy * dy;
    }
  
    // Returns the smallest circle that contains circles L and intersects circles B.
    function encloseN(L, B) {
      var circle,
          l0 = null,
          l1 = L.head,
          l2,
          p1;
  
      switch (B.length) {
        case 1: circle = enclose1(B[0]); break;
        case 2: circle = enclose2(B[0], B[1]); break;
        case 3: circle = enclose3(B[0], B[1], B[2]); break;
      }
  
      while (l1) {
        p1 = l1._, l2 = l1.next;
        if (!circle || !encloses(circle, p1)) {
  
          // Temporarily truncate L before l1.
          if (l0) L.tail = l0, l0.next = null;
          else L.head = L.tail = null;
  
          B.push(p1);
          circle = encloseN(L, B); // Note: reorders L!
          B.pop();
  
          // Move l1 to the front of L and reconnect the truncated list L.
          if (L.head) l1.next = L.head, L.head = l1;
          else l1.next = null, L.head = L.tail = l1;
          l0 = L.tail, l0.next = l2;
  
        } else {
          l0 = l1;
        }
        l1 = l2;
      }
  
      L.tail = l0;
      return circle;
    }
  
    function enclose1(a) {
      return {
        x: a.x,
        y: a.y,
        r: a.r
      };
    }
  
    function enclose2(a, b) {
      var x1 = a.x, y1 = a.y, r1 = a.r,
          x2 = b.x, y2 = b.y, r2 = b.r,
          x21 = x2 - x1, y21 = y2 - y1, r21 = r2 - r1,
          l = Math.sqrt(x21 * x21 + y21 * y21);
      return {
        x: (x1 + x2 + x21 / l * r21) / 2,
        y: (y1 + y2 + y21 / l * r21) / 2,
        r: (l + r1 + r2) / 2
      };
    }
  
    function enclose3(a, b, c) {
      var x1 = a.x, y1 = a.y, r1 = a.r,
          x2 = b.x, y2 = b.y, r2 = b.r,
          x3 = c.x, y3 = c.y, r3 = c.r,
          a2 = 2 * (x1 - x2),
          b2 = 2 * (y1 - y2),
          c2 = 2 * (r2 - r1),
          d2 = x1 * x1 + y1 * y1 - r1 * r1 - x2 * x2 - y2 * y2 + r2 * r2,
          a3 = 2 * (x1 - x3),
          b3 = 2 * (y1 - y3),
          c3 = 2 * (r3 - r1),
          d3 = x1 * x1 + y1 * y1 - r1 * r1 - x3 * x3 - y3 * y3 + r3 * r3,
          ab = a3 * b2 - a2 * b3,
          xa = (b2 * d3 - b3 * d2) / ab - x1,
          xb = (b3 * c2 - b2 * c3) / ab,
          ya = (a3 * d2 - a2 * d3) / ab - y1,
          yb = (a2 * c3 - a3 * c2) / ab,
          A = xb * xb + yb * yb - 1,
          B = 2 * (xa * xb + ya * yb + r1),
          C = xa * xa + ya * ya - r1 * r1,
          r = (-B - Math.sqrt(B * B - 4 * A * C)) / (2 * A);
      return {
        x: xa + xb * r + x1,
        y: ya + yb * r + y1,
        r: r
      };
    }
  
    function place(a, b, c) {
      var ax = a.x,
          ay = a.y,
          da = b.r + c.r,
          db = a.r + c.r,
          dx = b.x - ax,
          dy = b.y - ay,
          dc = dx * dx + dy * dy;
      if (dc) {
        var x = 0.5 + ((db *= db) - (da *= da)) / (2 * dc),
            y = Math.sqrt(Math.max(0, 2 * da * (db + dc) - (db -= dc) * db - da * da)) / (2 * dc);
        c.x = ax + x * dx + y * dy;
        c.y = ay + x * dy - y * dx;
      } else {
        c.x = ax + db;
        c.y = ay;
      }
    }
  
    function intersects(a, b) {
      var dx = b.x - a.x,
          dy = b.y - a.y,
          dr = a.r + b.r;
      return dr * dr > dx * dx + dy * dy;
    }
  
    function distance2(circle, x, y) {
      var dx = circle.x - x,
          dy = circle.y - y;
      return dx * dx + dy * dy;
    }
  
    function Node$1(circle) {
      this._ = circle;
      this.next = null;
      this.previous = null;
    }
  
    function packEnclose(circles) {
      if (!(n = circles.length)) return 0;
  
      var a, b, c, n;
  
      // Place the first circle.
      a = circles[0], a.x = 0, a.y = 0;
      if (!(n > 1)) return a.r;
  
      // Place the second circle.
      b = circles[1], a.x = -b.r, b.x = a.r, b.y = 0;
      if (!(n > 2)) return a.r + b.r;
  
      // Place the third circle.
      place(b, a, c = circles[2]);
  
      // Initialize the weighted centroid.
      var aa = a.r * a.r,
          ba = b.r * b.r,
          ca = c.r * c.r,
          oa = aa + ba + ca,
          ox = aa * a.x + ba * b.x + ca * c.x,
          oy = aa * a.y + ba * b.y + ca * c.y,
          cx, cy, i, j, k, sj, sk;
  
      // Initialize the front-chain using the first three circles a, b and c.
      a = new Node$1(a), b = new Node$1(b), c = new Node$1(c);
      a.next = c.previous = b;
      b.next = a.previous = c;
      c.next = b.previous = a;
  
      // Attempt to place each remaining circle…
      pack: for (i = 3; i < n; ++i) {
        place(a._, b._, c = circles[i]), c = new Node$1(c);
  
        // If there are only three elements in the front-chain…
        if ((k = a.previous) === (j = b.next)) {
          // If the new circle intersects the third circle,
          // rotate the front chain to try the next position.
          if (intersects(j._, c._)) {
            a = b, b = j, --i;
            continue pack;
          }
        }
  
        // Find the closest intersecting circle on the front-chain, if any.
        else {
          sj = j._.r, sk = k._.r;
          do {
            if (sj <= sk) {
              if (intersects(j._, c._)) {
                b = j, a.next = b, b.previous = a, --i;
                continue pack;
              }
              j = j.next, sj += j._.r;
            } else {
              if (intersects(k._, c._)) {
                a = k, a.next = b, b.previous = a, --i;
                continue pack;
              }
              k = k.previous, sk += k._.r;
            }
          } while (j !== k.next);
        }
  
        // Success! Insert the new circle c between a and b.
        c.previous = a, c.next = b, a.next = b.previous = b = c;
  
        // Update the weighted centroid.
        oa += ca = c._.r * c._.r;
        ox += ca * c._.x;
        oy += ca * c._.y;
  
        // Compute the new closest circle a to centroid.
        aa = distance2(a._, cx = ox / oa, cy = oy / oa);
        while ((c = c.next) !== b) {
          if ((ca = distance2(c._, cx, cy)) < aa) {
            a = c, aa = ca;
          }
        }
        b = a.next;
      }
  
      // Compute the enclosing circle of the front chain.
      a = [b._], c = b; while ((c = c.next) !== b) a.push(c._); c = enclose(a);
  
      // Translate the circles to put the enclosing circle around the origin.
      for (i = 0; i < n; ++i) a = circles[i], a.x -= c.x, a.y -= c.y;
  
      return c.r;
    }
  
    function siblings(circles) {
      packEnclose(circles);
      return circles;
    }
  
    function optional(f) {
      return f == null ? null : required(f);
    }
  
    function required(f) {
      if (typeof f !== "function") throw new Error;
      return f;
    }
  
    function constantZero() {
      return 0;
    }
  
    function constant$5(x) {
      return function() {
        return x;
      };
    }
  
    function defaultRadius(d) {
      return Math.sqrt(d.value);
    }
  
    function index() {
      var radius = null,
          dx = 1,
          dy = 1,
          padding = constantZero;
  
      function pack(root) {
        root.x = dx / 2, root.y = dy / 2;
        if (radius) {
          root.eachBefore(radiusLeaf(radius))
              .eachAfter(packChildren(padding, 0.5))
              .eachBefore(translateChild(1));
        } else {
          root.eachBefore(radiusLeaf(defaultRadius))
              .eachAfter(packChildren(constantZero, 1))
              .eachAfter(packChildren(padding, root.r / Math.min(dx, dy)))
              .eachBefore(translateChild(Math.min(dx, dy) / (2 * root.r)));
        }
        return root;
      }
  
      pack.radius = function(x) {
        return arguments.length ? (radius = optional(x), pack) : radius;
      };
  
      pack.size = function(x) {
        return arguments.length ? (dx = +x[0], dy = +x[1], pack) : [dx, dy];
      };
  
      pack.padding = function(x) {
        return arguments.length ? (padding = typeof x === "function" ? x : constant$5(+x), pack) : padding;
      };
  
      return pack;
    }
  
    function radiusLeaf(radius) {
      return function(node) {
        if (!node.children) {
          node.r = Math.max(0, +radius(node) || 0);
        }
      };
    }
  
    function packChildren(padding, k) {
      return function(node) {
        if (children = node.children) {
          var children,
              i,
              n = children.length,
              r = padding(node) * k || 0,
              e;
  
          if (r) for (i = 0; i < n; ++i) children[i].r += r;
          e = packEnclose(children);
          if (r) for (i = 0; i < n; ++i) children[i].r -= r;
          node.r = e + r;
        }
      };
    }
  
    function translateChild(k) {
      return function(node) {
        var parent = node.parent;
        node.r *= k;
        if (parent) {
          node.x = parent.x + k * node.x;
          node.y = parent.y + k * node.y;
        }
      };
    }
  
    function roundNode(node) {
      node.x0 = Math.round(node.x0);
      node.y0 = Math.round(node.y0);
      node.x1 = Math.round(node.x1);
      node.y1 = Math.round(node.y1);
    }
  
    function treemapDice(parent, x0, y0, x1, y1) {
      var nodes = parent.children,
          node,
          i = -1,
          n = nodes.length,
          k = parent.value && (x1 - x0) / parent.value;
  
      while (++i < n) {
        node = nodes[i], node.y0 = y0, node.y1 = y1;
        node.x0 = x0, node.x1 = x0 += node.value * k;
      }
    }
  
    function partition() {
      var dx = 1,
          dy = 1,
          padding = 0,
          round = false;
  
      function partition(root) {
        var n = root.height + 1;
        root.x0 =
        root.y0 = padding;
        root.x1 = dx;
        root.y1 = dy / n;
        root.eachBefore(positionNode(dy, n));
        if (round) root.eachBefore(roundNode);
        return root;
      }
  
      function positionNode(dy, n) {
        return function(node) {
          if (node.children) {
            treemapDice(node, node.x0, dy * (node.depth + 1) / n, node.x1, dy * (node.depth + 2) / n);
          }
          var x0 = node.x0,
              y0 = node.y0,
              x1 = node.x1 - padding,
              y1 = node.y1 - padding;
          if (x1 < x0) x0 = x1 = (x0 + x1) / 2;
          if (y1 < y0) y0 = y1 = (y0 + y1) / 2;
          node.x0 = x0;
          node.y0 = y0;
          node.x1 = x1;
          node.y1 = y1;
        };
      }
  
      partition.round = function(x) {
        return arguments.length ? (round = !!x, partition) : round;
      };
  
      partition.size = function(x) {
        return arguments.length ? (dx = +x[0], dy = +x[1], partition) : [dx, dy];
      };
  
      partition.padding = function(x) {
        return arguments.length ? (padding = +x, partition) : padding;
      };
  
      return partition;
    }
  
  var   keyPrefix$1 = "$";
    var preroot = {depth: -1};
    var ambiguous = {};
    function defaultId(d) {
      return d.id;
    }
  
    function defaultParentId(d) {
      return d.parentId;
    }
  
    function stratify() {
      var id = defaultId,
          parentId = defaultParentId;
  
      function stratify(data) {
        var d,
            i,
            n = data.length,
            root,
            parent,
            node,
            nodes = new Array(n),
            nodeId,
            nodeKey,
            nodeByKey = {};
  
        for (i = 0; i < n; ++i) {
          d = data[i], node = nodes[i] = new Node(d);
          if ((nodeId = id(d, i, data)) != null && (nodeId += "")) {
            nodeKey = keyPrefix$1 + (node.id = nodeId);
            nodeByKey[nodeKey] = nodeKey in nodeByKey ? ambiguous : node;
          }
        }
  
        for (i = 0; i < n; ++i) {
          node = nodes[i], nodeId = parentId(data[i], i, data);
          if (nodeId == null || !(nodeId += "")) {
            if (root) throw new Error("multiple roots");
            root = node;
          } else {
            parent = nodeByKey[keyPrefix$1 + nodeId];
            if (!parent) throw new Error("missing: " + nodeId);
            if (parent === ambiguous) throw new Error("ambiguous: " + nodeId);
            if (parent.children) parent.children.push(node);
            else parent.children = [node];
            node.parent = parent;
          }
        }
  
        if (!root) throw new Error("no root");
        root.parent = preroot;
        root.eachBefore(function(node) { node.depth = node.parent.depth + 1; --n; }).eachBefore(computeHeight);
        root.parent = null;
        if (n > 0) throw new Error("cycle");
  
        return root;
      }
  
      stratify.id = function(x) {
        return arguments.length ? (id = required(x), stratify) : id;
      };
  
      stratify.parentId = function(x) {
        return arguments.length ? (parentId = required(x), stratify) : parentId;
      };
  
      return stratify;
    }
  
    function defaultSeparation$1(a, b) {
      return a.parent === b.parent ? 1 : 2;
    }
  
    // function radialSeparation(a, b) {
    //   return (a.parent === b.parent ? 1 : 2) / a.depth;
    // }
  
    // This function is used to traverse the left contour of a subtree (or
    // subforest). It returns the successor of v on this contour. This successor is
    // either given by the leftmost child of v or by the thread of v. The function
    // returns null if and only if v is on the highest level of its subtree.
    function nextLeft(v) {
      var children = v.children;
      return children ? children[0] : v.t;
    }
  
    // This function works analogously to nextLeft.
    function nextRight(v) {
      var children = v.children;
      return children ? children[children.length - 1] : v.t;
    }
  
    // Shifts the current subtree rooted at w+. This is done by increasing
    // prelim(w+) and mod(w+) by shift.
    function moveSubtree(wm, wp, shift) {
      var change = shift / (wp.i - wm.i);
      wp.c -= change;
      wp.s += shift;
      wm.c += change;
      wp.z += shift;
      wp.m += shift;
    }
  
    // All other shifts, applied to the smaller subtrees between w- and w+, are
    // performed by this function. To prepare the shifts, we have to adjust
    // change(w+), shift(w+), and change(w-).
    function executeShifts(v) {
      var shift = 0,
          change = 0,
          children = v.children,
          i = children.length,
          w;
      while (--i >= 0) {
        w = children[i];
        w.z += shift;
        w.m += shift;
        shift += w.s + (change += w.c);
      }
    }
  
    // If vi-’s ancestor is a sibling of v, returns vi-’s ancestor. Otherwise,
    // returns the specified (default) ancestor.
    function nextAncestor(vim, v, ancestor) {
      return vim.a.parent === v.parent ? vim.a : ancestor;
    }
  
    function TreeNode(node, i) {
      this._ = node;
      this.parent = null;
      this.children = null;
      this.A = null; // default ancestor
      this.a = this; // ancestor
      this.z = 0; // prelim
      this.m = 0; // mod
      this.c = 0; // change
      this.s = 0; // shift
      this.t = null; // thread
      this.i = i; // number
    }
  
    TreeNode.prototype = Object.create(Node.prototype);
  
    function treeRoot(root) {
      var tree = new TreeNode(root, 0),
          node,
          nodes = [tree],
          child,
          children,
          i,
          n;
  
      while (node = nodes.pop()) {
        if (children = node._.children) {
          node.children = new Array(n = children.length);
          for (i = n - 1; i >= 0; --i) {
            nodes.push(child = node.children[i] = new TreeNode(children[i], i));
            child.parent = node;
          }
        }
      }
  
      (tree.parent = new TreeNode(null, 0)).children = [tree];
      return tree;
    }
  
    // Node-link tree diagram using the Reingold-Tilford "tidy" algorithm
    function tree() {
      var separation = defaultSeparation$1,
          dx = 1,
          dy = 1,
          nodeSize = null;
  
      function tree(root) {
        var t = treeRoot(root);
  
        // Compute the layout using Buchheim et al.’s algorithm.
        t.eachAfter(firstWalk), t.parent.m = -t.z;
        t.eachBefore(secondWalk);
  
        // If a fixed node size is specified, scale x and y.
        if (nodeSize) root.eachBefore(sizeNode);
  
        // If a fixed tree size is specified, scale x and y based on the extent.
        // Compute the left-most, right-most, and depth-most nodes for extents.
        else {
          var left = root,
              right = root,
              bottom = root;
          root.eachBefore(function(node) {
            if (node.x < left.x) left = node;
            if (node.x > right.x) right = node;
            if (node.depth > bottom.depth) bottom = node;
          });
          var s = left === right ? 1 : separation(left, right) / 2,
              tx = s - left.x,
              kx = dx / (right.x + s + tx),
              ky = dy / (bottom.depth || 1);
          root.eachBefore(function(node) {
            node.x = (node.x + tx) * kx;
            node.y = node.depth * ky;
          });
        }
  
        return root;
      }
  
      // Computes a preliminary x-coordinate for v. Before that, FIRST WALK is
      // applied recursively to the children of v, as well as the function
      // APPORTION. After spacing out the children by calling EXECUTE SHIFTS, the
      // node v is placed to the midpoint of its outermost children.
      function firstWalk(v) {
        var children = v.children,
            siblings = v.parent.children,
            w = v.i ? siblings[v.i - 1] : null;
        if (children) {
          executeShifts(v);
          var midpoint = (children[0].z + children[children.length - 1].z) / 2;
          if (w) {
            v.z = w.z + separation(v._, w._);
            v.m = v.z - midpoint;
          } else {
            v.z = midpoint;
          }
        } else if (w) {
          v.z = w.z + separation(v._, w._);
        }
        v.parent.A = apportion(v, w, v.parent.A || siblings[0]);
      }
  
      // Computes all real x-coordinates by summing up the modifiers recursively.
      function secondWalk(v) {
        v._.x = v.z + v.parent.m;
        v.m += v.parent.m;
      }
  
      // The core of the algorithm. Here, a new subtree is combined with the
      // previous subtrees. Threads are used to traverse the inside and outside
      // contours of the left and right subtree up to the highest common level. The
      // vertices used for the traversals are vi+, vi-, vo-, and vo+, where the
      // superscript o means outside and i means inside, the subscript - means left
      // subtree and + means right subtree. For summing up the modifiers along the
      // contour, we use respective variables si+, si-, so-, and so+. Whenever two
      // nodes of the inside contours conflict, we compute the left one of the
      // greatest uncommon ancestors using the function ANCESTOR and call MOVE
      // SUBTREE to shift the subtree and prepare the shifts of smaller subtrees.
      // Finally, we add a new thread (if necessary).
      function apportion(v, w, ancestor) {
        if (w) {
          var vip = v,
              vop = v,
              vim = w,
              vom = vip.parent.children[0],
              sip = vip.m,
              sop = vop.m,
              sim = vim.m,
              som = vom.m,
              shift;
          while (vim = nextRight(vim), vip = nextLeft(vip), vim && vip) {
            vom = nextLeft(vom);
            vop = nextRight(vop);
            vop.a = v;
            shift = vim.z + sim - vip.z - sip + separation(vim._, vip._);
            if (shift > 0) {
              moveSubtree(nextAncestor(vim, v, ancestor), v, shift);
              sip += shift;
              sop += shift;
            }
            sim += vim.m;
            sip += vip.m;
            som += vom.m;
            sop += vop.m;
          }
          if (vim && !nextRight(vop)) {
            vop.t = vim;
            vop.m += sim - sop;
          }
          if (vip && !nextLeft(vom)) {
            vom.t = vip;
            vom.m += sip - som;
            ancestor = v;
          }
        }
        return ancestor;
      }
  
      function sizeNode(node) {
        node.x *= dx;
        node.y = node.depth * dy;
      }
  
      tree.separation = function(x) {
        return arguments.length ? (separation = x, tree) : separation;
      };
  
      tree.size = function(x) {
        return arguments.length ? (nodeSize = false, dx = +x[0], dy = +x[1], tree) : (nodeSize ? null : [dx, dy]);
      };
  
      tree.nodeSize = function(x) {
        return arguments.length ? (nodeSize = true, dx = +x[0], dy = +x[1], tree) : (nodeSize ? [dx, dy] : null);
      };
  
      return tree;
    }
  
    function treemapSlice(parent, x0, y0, x1, y1) {
      var nodes = parent.children,
          node,
          i = -1,
          n = nodes.length,
          k = parent.value && (y1 - y0) / parent.value;
  
      while (++i < n) {
        node = nodes[i], node.x0 = x0, node.x1 = x1;
        node.y0 = y0, node.y1 = y0 += node.value * k;
      }
    }
  
    var phi = (1 + Math.sqrt(5)) / 2;
  
    function squarifyRatio(ratio, parent, x0, y0, x1, y1) {
      var rows = [],
          nodes = parent.children,
          row,
          nodeValue,
          i0 = 0,
          i1,
          n = nodes.length,
          dx, dy,
          value = parent.value,
          sumValue,
          minValue,
          maxValue,
          newRatio,
          minRatio,
          alpha,
          beta;
  
      while (i0 < n) {
        dx = x1 - x0, dy = y1 - y0;
        minValue = maxValue = sumValue = nodes[i0].value;
        alpha = Math.max(dy / dx, dx / dy) / (value * ratio);
        beta = sumValue * sumValue * alpha;
        minRatio = Math.max(maxValue / beta, beta / minValue);
  
        // Keep adding nodes while the aspect ratio maintains or improves.
        for (i1 = i0 + 1; i1 < n; ++i1) {
          sumValue += nodeValue = nodes[i1].value;
          if (nodeValue < minValue) minValue = nodeValue;
          if (nodeValue > maxValue) maxValue = nodeValue;
          beta = sumValue * sumValue * alpha;
          newRatio = Math.max(maxValue / beta, beta / minValue);
          if (newRatio > minRatio) { sumValue -= nodeValue; break; }
          minRatio = newRatio;
        }
  
        // Position and record the row orientation.
        rows.push(row = {value: sumValue, dice: dx < dy, children: nodes.slice(i0, i1)});
        if (row.dice) treemapDice(row, x0, y0, x1, value ? y0 += dy * sumValue / value : y1);
        else treemapSlice(row, x0, y0, value ? x0 += dx * sumValue / value : x1, y1);
        value -= sumValue, i0 = i1;
      }
  
      return rows;
    }
  
    var squarify = (function custom(ratio) {
  
      function squarify(parent, x0, y0, x1, y1) {
        squarifyRatio(ratio, parent, x0, y0, x1, y1);
      }
  
      squarify.ratio = function(x) {
        return custom((x = +x) > 1 ? x : 1);
      };
  
      return squarify;
    })(phi);
  
    function index$1() {
      var tile = squarify,
          round = false,
          dx = 1,
          dy = 1,
          paddingStack = [0],
          paddingInner = constantZero,
          paddingTop = constantZero,
          paddingRight = constantZero,
          paddingBottom = constantZero,
          paddingLeft = constantZero;
  
      function treemap(root) {
        root.x0 =
        root.y0 = 0;
        root.x1 = dx;
        root.y1 = dy;
        root.eachBefore(positionNode);
        paddingStack = [0];
        if (round) root.eachBefore(roundNode);
        return root;
      }
  
      function positionNode(node) {
        var p = paddingStack[node.depth],
            x0 = node.x0 + p,
            y0 = node.y0 + p,
            x1 = node.x1 - p,
            y1 = node.y1 - p;
        if (x1 < x0) x0 = x1 = (x0 + x1) / 2;
        if (y1 < y0) y0 = y1 = (y0 + y1) / 2;
        node.x0 = x0;
        node.y0 = y0;
        node.x1 = x1;
        node.y1 = y1;
        if (node.children) {
          p = paddingStack[node.depth + 1] = paddingInner(node) / 2;
          x0 += paddingLeft(node) - p;
          y0 += paddingTop(node) - p;
          x1 -= paddingRight(node) - p;
          y1 -= paddingBottom(node) - p;
          if (x1 < x0) x0 = x1 = (x0 + x1) / 2;
          if (y1 < y0) y0 = y1 = (y0 + y1) / 2;
          tile(node, x0, y0, x1, y1);
        }
      }
  
      treemap.round = function(x) {
        return arguments.length ? (round = !!x, treemap) : round;
      };
  
      treemap.size = function(x) {
        return arguments.length ? (dx = +x[0], dy = +x[1], treemap) : [dx, dy];
      };
  
      treemap.tile = function(x) {
        return arguments.length ? (tile = required(x), treemap) : tile;
      };
  
      treemap.padding = function(x) {
        return arguments.length ? treemap.paddingInner(x).paddingOuter(x) : treemap.paddingInner();
      };
  
      treemap.paddingInner = function(x) {
        return arguments.length ? (paddingInner = typeof x === "function" ? x : constant$5(+x), treemap) : paddingInner;
      };
  
      treemap.paddingOuter = function(x) {
        return arguments.length ? treemap.paddingTop(x).paddingRight(x).paddingBottom(x).paddingLeft(x) : treemap.paddingTop();
      };
  
      treemap.paddingTop = function(x) {
        return arguments.length ? (paddingTop = typeof x === "function" ? x : constant$5(+x), treemap) : paddingTop;
      };
  
      treemap.paddingRight = function(x) {
        return arguments.length ? (paddingRight = typeof x === "function" ? x : constant$5(+x), treemap) : paddingRight;
      };
  
      treemap.paddingBottom = function(x) {
        return arguments.length ? (paddingBottom = typeof x === "function" ? x : constant$5(+x), treemap) : paddingBottom;
      };
  
      treemap.paddingLeft = function(x) {
        return arguments.length ? (paddingLeft = typeof x === "function" ? x : constant$5(+x), treemap) : paddingLeft;
      };
  
      return treemap;
    }
  
    function binary(parent, x0, y0, x1, y1) {
      var nodes = parent.children,
          i, n = nodes.length,
          sum, sums = new Array(n + 1);
  
      for (sums[0] = sum = i = 0; i < n; ++i) {
        sums[i + 1] = sum += nodes[i].value;
      }
  
      partition(0, n, parent.value, x0, y0, x1, y1);
  
      function partition(i, j, value, x0, y0, x1, y1) {
        if (i >= j - 1) {
          var node = nodes[i];
          node.x0 = x0, node.y0 = y0;
          node.x1 = x1, node.y1 = y1;
          return;
        }
  
        var valueOffset = sums[i],
            valueTarget = (value / 2) + valueOffset,
            k = i + 1,
            hi = j - 1;
  
        while (k < hi) {
          var mid = k + hi >>> 1;
          if (sums[mid] < valueTarget) k = mid + 1;
          else hi = mid;
        }
  
        var valueLeft = sums[k] - valueOffset,
            valueRight = value - valueLeft;
  
        if ((y1 - y0) > (x1 - x0)) {
          var yk = (y0 * valueRight + y1 * valueLeft) / value;
          partition(i, k, valueLeft, x0, y0, x1, yk);
          partition(k, j, valueRight, x0, yk, x1, y1);
        } else {
          var xk = (x0 * valueRight + x1 * valueLeft) / value;
          partition(i, k, valueLeft, x0, y0, xk, y1);
          partition(k, j, valueRight, xk, y0, x1, y1);
        }
      }
    }
  
    function sliceDice(parent, x0, y0, x1, y1) {
      (parent.depth & 1 ? treemapSlice : treemapDice)(parent, x0, y0, x1, y1);
    }
  
    var resquarify = (function custom(ratio) {
  
      function resquarify(parent, x0, y0, x1, y1) {
        if ((rows = parent._squarify) && (rows.ratio === ratio)) {
          var rows,
              row,
              nodes,
              i,
              j = -1,
              n,
              m = rows.length,
              value = parent.value;
  
          while (++j < m) {
            row = rows[j], nodes = row.children;
            for (i = row.value = 0, n = nodes.length; i < n; ++i) row.value += nodes[i].value;
            if (row.dice) treemapDice(row, x0, y0, x1, y0 += (y1 - y0) * row.value / value);
            else treemapSlice(row, x0, y0, x0 += (x1 - x0) * row.value / value, y1);
            value -= row.value;
          }
        } else {
          parent._squarify = rows = squarifyRatio(ratio, parent, x0, y0, x1, y1);
          rows.ratio = ratio;
        }
      }
  
      resquarify.ratio = function(x) {
        return custom((x = +x) > 1 ? x : 1);
      };
  
      return resquarify;
    })(phi);
  
    function center$1(x, y) {
      var nodes;
  
      if (x == null) x = 0;
      if (y == null) y = 0;
  
      function force() {
        var i,
            n = nodes.length,
            node,
            sx = 0,
            sy = 0;
  
        for (i = 0; i < n; ++i) {
          node = nodes[i], sx += node.x, sy += node.y;
        }
  
        for (sx = sx / n - x, sy = sy / n - y, i = 0; i < n; ++i) {
          node = nodes[i], node.x -= sx, node.y -= sy;
        }
      }
  
      force.initialize = function(_) {
        nodes = _;
      };
  
      force.x = function(_) {
        return arguments.length ? (x = +_, force) : x;
      };
  
      force.y = function(_) {
        return arguments.length ? (y = +_, force) : y;
      };
  
      return force;
    }
  
    function constant$6(x) {
      return function() {
        return x;
      };
    }
  
    function jiggle() {
      return (Math.random() - 0.5) * 1e-6;
    }
  
    function x$1(d) {
      return d.x + d.vx;
    }
  
    function y$1(d) {
      return d.y + d.vy;
    }
  
    function collide(radius) {
      var nodes,
          radii,
          strength = 1,
          iterations = 1;
  
      if (typeof radius !== "function") radius = constant$6(radius == null ? 1 : +radius);
  
      function force() {
        var i, n = nodes.length,
            tree,
            node,
            xi,
            yi,
            ri,
            ri2;
  
        for (var k = 0; k < iterations; ++k) {
          tree = quadtree(nodes, x$1, y$1).visitAfter(prepare);
          for (i = 0; i < n; ++i) {
            node = nodes[i];
            ri = radii[i], ri2 = ri * ri;
            xi = node.x + node.vx;
            yi = node.y + node.vy;
            tree.visit(apply);
          }
        }
  
        function apply(quad, x0, y0, x1, y1) {
          var data = quad.data, rj = quad.r, r = ri + rj;
          if (data) {
            if (data.index > i) {
              var x = xi - data.x - data.vx,
                  y = yi - data.y - data.vy,
                  l = x * x + y * y;
              if (l < r * r) {
                if (x === 0) x = jiggle(), l += x * x;
                if (y === 0) y = jiggle(), l += y * y;
                l = (r - (l = Math.sqrt(l))) / l * strength;
                node.vx += (x *= l) * (r = (rj *= rj) / (ri2 + rj));
                node.vy += (y *= l) * r;
                data.vx -= x * (r = 1 - r);
                data.vy -= y * r;
              }
            }
            return;
          }
          return x0 > xi + r || x1 < xi - r || y0 > yi + r || y1 < yi - r;
        }
      }
  
      function prepare(quad) {
        if (quad.data) return quad.r = radii[quad.data.index];
        for (var i = quad.r = 0; i < 4; ++i) {
          if (quad[i] && quad[i].r > quad.r) {
            quad.r = quad[i].r;
          }
        }
      }
  
      force.initialize = function(_) {
        var i, n = (nodes = _).length; radii = new Array(n);
        for (i = 0; i < n; ++i) radii[i] = +radius(nodes[i], i, nodes);
      };
  
      force.iterations = function(_) {
        return arguments.length ? (iterations = +_, force) : iterations;
      };
  
      force.strength = function(_) {
        return arguments.length ? (strength = +_, force) : strength;
      };
  
      force.radius = function(_) {
        return arguments.length ? (radius = typeof _ === "function" ? _ : constant$6(+_), force) : radius;
      };
  
      return force;
    }
  
    function index$2(d, i) {
      return i;
    }
  
    function link(links) {
      var id = index$2,
          strength = defaultStrength,
          strengths,
          distance = constant$6(30),
          distances,
          nodes,
          count,
          bias,
          iterations = 1;
  
      if (links == null) links = [];
  
      function defaultStrength(link) {
        return 1 / Math.min(count[link.source.index], count[link.target.index]);
      }
  
      function force(alpha) {
        for (var k = 0, n = links.length; k < iterations; ++k) {
          for (var i = 0, link, source, target, x, y, l, b; i < n; ++i) {
            link = links[i], source = link.source, target = link.target;
            x = target.x + target.vx - source.x - source.vx || jiggle();
            y = target.y + target.vy - source.y - source.vy || jiggle();
            l = Math.sqrt(x * x + y * y);
            l = (l - distances[i]) / l * alpha * strengths[i];
            x *= l, y *= l;
            target.vx -= x * (b = bias[i]);
            target.vy -= y * b;
            source.vx += x * (b = 1 - b);
            source.vy += y * b;
          }
        }
      }
  
      function initialize() {
        if (!nodes) return;
  
        var i,
            n = nodes.length,
            m = links.length,
            nodeById = map$1(nodes, id),
            link;
  
        for (i = 0, count = new Array(n); i < n; ++i) {
          count[i] = 0;
        }
  
        for (i = 0; i < m; ++i) {
          link = links[i], link.index = i;
          if (typeof link.source !== "object") link.source = nodeById.get(link.source);
          if (typeof link.target !== "object") link.target = nodeById.get(link.target);
          ++count[link.source.index], ++count[link.target.index];
        }
  
        for (i = 0, bias = new Array(m); i < m; ++i) {
          link = links[i], bias[i] = count[link.source.index] / (count[link.source.index] + count[link.target.index]);
        }
  
        strengths = new Array(m), initializeStrength();
        distances = new Array(m), initializeDistance();
      }
  
      function initializeStrength() {
        if (!nodes) return;
  
        for (var i = 0, n = links.length; i < n; ++i) {
          strengths[i] = +strength(links[i], i, links);
        }
      }
  
      function initializeDistance() {
        if (!nodes) return;
  
        for (var i = 0, n = links.length; i < n; ++i) {
          distances[i] = +distance(links[i], i, links);
        }
      }
  
      force.initialize = function(_) {
        nodes = _;
        initialize();
      };
  
      force.links = function(_) {
        return arguments.length ? (links = _, initialize(), force) : links;
      };
  
      force.id = function(_) {
        return arguments.length ? (id = _, force) : id;
      };
  
      force.iterations = function(_) {
        return arguments.length ? (iterations = +_, force) : iterations;
      };
  
      force.strength = function(_) {
        return arguments.length ? (strength = typeof _ === "function" ? _ : constant$6(+_), initializeStrength(), force) : strength;
      };
  
      force.distance = function(_) {
        return arguments.length ? (distance = typeof _ === "function" ? _ : constant$6(+_), initializeDistance(), force) : distance;
      };
  
      return force;
    }
  
    function x$2(d) {
      return d.x;
    }
  
    function y$2(d) {
      return d.y;
    }
  
    var initialRadius = 10;
    var initialAngle = Math.PI * (3 - Math.sqrt(5));
    function simulation(nodes) {
      var simulation,
          alpha = 1,
          alphaMin = 0.001,
          alphaDecay = 1 - Math.pow(alphaMin, 1 / 300),
          alphaTarget = 0,
          velocityDecay = 0.6,
          forces = map$1(),
          stepper = timer(step),
          event = dispatch("tick", "end");
  
      if (nodes == null) nodes = [];
  
      function step() {
        tick();
        event.call("tick", simulation);
        if (alpha < alphaMin) {
          stepper.stop();
          event.call("end", simulation);
        }
      }
  
      function tick() {
        var i, n = nodes.length, node;
  
        alpha += (alphaTarget - alpha) * alphaDecay;
  
        forces.each(function(force) {
          force(alpha);
        });
  
        for (i = 0; i < n; ++i) {
          node = nodes[i];
          if (node.fx == null) node.x += node.vx *= velocityDecay;
          else node.x = node.fx, node.vx = 0;
          if (node.fy == null) node.y += node.vy *= velocityDecay;
          else node.y = node.fy, node.vy = 0;
        }
      }
  
      function initializeNodes() {
        for (var i = 0, n = nodes.length, node; i < n; ++i) {
          node = nodes[i], node.index = i;
          if (isNaN(node.x) || isNaN(node.y)) {
            var radius = initialRadius * Math.sqrt(i), angle = i * initialAngle;
            node.x = radius * Math.cos(angle);
            node.y = radius * Math.sin(angle);
          }
          if (isNaN(node.vx) || isNaN(node.vy)) {
            node.vx = node.vy = 0;
          }
        }
      }
  
      function initializeForce(force) {
        if (force.initialize) force.initialize(nodes);
        return force;
      }
  
      initializeNodes();
  
      return simulation = {
        tick: tick,
  
        restart: function() {
          return stepper.restart(step), simulation;
        },
  
        stop: function() {
          return stepper.stop(), simulation;
        },
  
        nodes: function(_) {
          return arguments.length ? (nodes = _, initializeNodes(), forces.each(initializeForce), simulation) : nodes;
        },
  
        alpha: function(_) {
          return arguments.length ? (alpha = +_, simulation) : alpha;
        },
  
        alphaMin: function(_) {
          return arguments.length ? (alphaMin = +_, simulation) : alphaMin;
        },
  
        alphaDecay: function(_) {
          return arguments.length ? (alphaDecay = +_, simulation) : +alphaDecay;
        },
  
        alphaTarget: function(_) {
          return arguments.length ? (alphaTarget = +_, simulation) : alphaTarget;
        },
  
        velocityDecay: function(_) {
          return arguments.length ? (velocityDecay = 1 - _, simulation) : 1 - velocityDecay;
        },
  
        force: function(name, _) {
          return arguments.length > 1 ? ((_ == null ? forces.remove(name) : forces.set(name, initializeForce(_))), simulation) : forces.get(name);
        },
  
        find: function(x, y, radius) {
          var i = 0,
              n = nodes.length,
              dx,
              dy,
              d2,
              node,
              closest;
  
          if (radius == null) radius = Infinity;
          else radius *= radius;
  
          for (i = 0; i < n; ++i) {
            node = nodes[i];
            dx = x - node.x;
            dy = y - node.y;
            d2 = dx * dx + dy * dy;
            if (d2 < radius) closest = node, radius = d2;
          }
  
          return closest;
        },
  
        on: function(name, _) {
          return arguments.length > 1 ? (event.on(name, _), simulation) : event.on(name);
        }
      };
    }
  
    function manyBody() {
      var nodes,
          node,
          alpha,
          strength = constant$6(-30),
          strengths,
          distanceMin2 = 1,
          distanceMax2 = Infinity,
          theta2 = 0.81;
  
      function force(_) {
        var i, n = nodes.length, tree = quadtree(nodes, x$2, y$2).visitAfter(accumulate);
        for (alpha = _, i = 0; i < n; ++i) node = nodes[i], tree.visit(apply);
      }
  
      function initialize() {
        if (!nodes) return;
        var i, n = nodes.length;
        strengths = new Array(n);
        for (i = 0; i < n; ++i) strengths[i] = +strength(nodes[i], i, nodes);
      }
  
      function accumulate(quad) {
        var strength = 0, q, c, x, y, i;
  
        // For internal nodes, accumulate forces from child quadrants.
        if (quad.length) {
          for (x = y = i = 0; i < 4; ++i) {
            if ((q = quad[i]) && (c = q.value)) {
              strength += c, x += c * q.x, y += c * q.y;
            }
          }
          quad.x = x / strength;
          quad.y = y / strength;
        }
  
        // For leaf nodes, accumulate forces from coincident quadrants.
        else {
          q = quad;
          q.x = q.data.x;
          q.y = q.data.y;
          do strength += strengths[q.data.index];
          while (q = q.next);
        }
  
        quad.value = strength;
      }
  
      function apply(quad, x1, _, x2) {
        if (!quad.value) return true;
  
        var x = quad.x - node.x,
            y = quad.y - node.y,
            w = x2 - x1,
            l = x * x + y * y;
  
        // Apply the Barnes-Hut approximation if possible.
        // Limit forces for very close nodes; randomize direction if coincident.
        if (w * w / theta2 < l) {
          if (l < distanceMax2) {
            if (x === 0) x = jiggle(), l += x * x;
            if (y === 0) y = jiggle(), l += y * y;
            if (l < distanceMin2) l = Math.sqrt(distanceMin2 * l);
            node.vx += x * quad.value * alpha / l;
            node.vy += y * quad.value * alpha / l;
          }
          return true;
        }
  
        // Otherwise, process points directly.
        else if (quad.length || l >= distanceMax2) return;
  
        // Limit forces for very close nodes; randomize direction if coincident.
        if (quad.data !== node || quad.next) {
          if (x === 0) x = jiggle(), l += x * x;
          if (y === 0) y = jiggle(), l += y * y;
          if (l < distanceMin2) l = Math.sqrt(distanceMin2 * l);
        }
  
        do if (quad.data !== node) {
          w = strengths[quad.data.index] * alpha / l;
          node.vx += x * w;
          node.vy += y * w;
        } while (quad = quad.next);
      }
  
      force.initialize = function(_) {
        nodes = _;
        initialize();
      };
  
      force.strength = function(_) {
        return arguments.length ? (strength = typeof _ === "function" ? _ : constant$6(+_), initialize(), force) : strength;
      };
  
      force.distanceMin = function(_) {
        return arguments.length ? (distanceMin2 = _ * _, force) : Math.sqrt(distanceMin2);
      };
  
      force.distanceMax = function(_) {
        return arguments.length ? (distanceMax2 = _ * _, force) : Math.sqrt(distanceMax2);
      };
  
      force.theta = function(_) {
        return arguments.length ? (theta2 = _ * _, force) : Math.sqrt(theta2);
      };
  
      return force;
    }
  
    function x$3(x) {
      var strength = constant$6(0.1),
          nodes,
          strengths,
          xz;
  
      if (typeof x !== "function") x = constant$6(x == null ? 0 : +x);
  
      function force(alpha) {
        for (var i = 0, n = nodes.length, node; i < n; ++i) {
          node = nodes[i], node.vx += (xz[i] - node.x) * strengths[i] * alpha;
        }
      }
  
      function initialize() {
        if (!nodes) return;
        var i, n = nodes.length;
        strengths = new Array(n);
        xz = new Array(n);
        for (i = 0; i < n; ++i) {
          strengths[i] = isNaN(xz[i] = +x(nodes[i], i, nodes)) ? 0 : +strength(nodes[i], i, nodes);
        }
      }
  
      force.initialize = function(_) {
        nodes = _;
        initialize();
      };
  
      force.strength = function(_) {
        return arguments.length ? (strength = typeof _ === "function" ? _ : constant$6(+_), initialize(), force) : strength;
      };
  
      force.x = function(_) {
        return arguments.length ? (x = typeof _ === "function" ? _ : constant$6(+_), initialize(), force) : x;
      };
  
      return force;
    }
  
    function y$3(y) {
      var strength = constant$6(0.1),
          nodes,
          strengths,
          yz;
  
      if (typeof y !== "function") y = constant$6(y == null ? 0 : +y);
  
      function force(alpha) {
        for (var i = 0, n = nodes.length, node; i < n; ++i) {
          node = nodes[i], node.vy += (yz[i] - node.y) * strengths[i] * alpha;
        }
      }
  
      function initialize() {
        if (!nodes) return;
        var i, n = nodes.length;
        strengths = new Array(n);
        yz = new Array(n);
        for (i = 0; i < n; ++i) {
          strengths[i] = isNaN(yz[i] = +y(nodes[i], i, nodes)) ? 0 : +strength(nodes[i], i, nodes);
        }
      }
  
      force.initialize = function(_) {
        nodes = _;
        initialize();
      };
  
      force.strength = function(_) {
        return arguments.length ? (strength = typeof _ === "function" ? _ : constant$6(+_), initialize(), force) : strength;
      };
  
      force.y = function(_) {
        return arguments.length ? (y = typeof _ === "function" ? _ : constant$6(+_), initialize(), force) : y;
      };
  
      return force;
    }
  
    function nopropagation() {
      exports.event.stopImmediatePropagation();
    }
  
    function noevent() {
      exports.event.preventDefault();
      exports.event.stopImmediatePropagation();
    }
  
    function dragDisable(view) {
      var root = view.document.documentElement,
          selection = select(view).on("dragstart.drag", noevent, true);
      if ("onselectstart" in root) {
        selection.on("selectstart.drag", noevent, true);
      } else {
        root.__noselect = root.style.MozUserSelect;
        root.style.MozUserSelect = "none";
      }
    }
  
    function dragEnable(view, noclick) {
      var root = view.document.documentElement,
          selection = select(view).on("dragstart.drag", null);
      if (noclick) {
        selection.on("click.drag", noevent, true);
        setTimeout(function() { selection.on("click.drag", null); }, 0);
      }
      if ("onselectstart" in root) {
        selection.on("selectstart.drag", null);
      } else {
        root.style.MozUserSelect = root.__noselect;
        delete root.__noselect;
      }
    }
  
    function constant$7(x) {
      return function() {
        return x;
      };
    }
  
    function DragEvent(target, type, subject, id, active, x, y, dx, dy, dispatch) {
      this.target = target;
      this.type = type;
      this.subject = subject;
      this.identifier = id;
      this.active = active;
      this.x = x;
      this.y = y;
      this.dx = dx;
      this.dy = dy;
      this._ = dispatch;
    }
  
    DragEvent.prototype.on = function() {
      var value = this._.on.apply(this._, arguments);
      return value === this._ ? this : value;
    };
  
    // Ignore right-click, since that should open the context menu.
    function defaultFilter() {
      return !exports.event.button;
    }
  
    function defaultContainer() {
      return this.parentNode;
    }
  
    function defaultSubject(d) {
      return d == null ? {x: exports.event.x, y: exports.event.y} : d;
    }
  
    function drag() {
      var filter = defaultFilter,
          container = defaultContainer,
          subject = defaultSubject,
          gestures = {},
          listeners = dispatch("start", "drag", "end"),
          active = 0,
          mousemoving,
          touchending;
  
      function drag(selection) {
        selection
            .on("mousedown.drag", mousedowned)
            .on("touchstart.drag", touchstarted)
            .on("touchmove.drag", touchmoved)
            .on("touchend.drag touchcancel.drag", touchended)
            .style("-webkit-tap-highlight-color", "rgba(0,0,0,0)");
      }
  
      function mousedowned() {
        if (touchending || !filter.apply(this, arguments)) return;
        var gesture = beforestart("mouse", container.apply(this, arguments), mouse, this, arguments);
        if (!gesture) return;
        select(exports.event.view).on("mousemove.drag", mousemoved, true).on("mouseup.drag", mouseupped, true);
        dragDisable(exports.event.view);
        nopropagation();
        mousemoving = false;
        gesture("start");
      }
  
      function mousemoved() {
        noevent();
        mousemoving = true;
        gestures.mouse("drag");
      }
  
      function mouseupped() {
        select(exports.event.view).on("mousemove.drag mouseup.drag", null);
        dragEnable(exports.event.view, mousemoving);
        noevent();
        gestures.mouse("end");
      }
  
      function touchstarted() {
        if (!filter.apply(this, arguments)) return;
        var touches = exports.event.changedTouches,
            c = container.apply(this, arguments),
            n = touches.length, i, gesture;
  
        for (i = 0; i < n; ++i) {
          if (gesture = beforestart(touches[i].identifier, c, touch, this, arguments)) {
            nopropagation();
            gesture("start");
          }
        }
      }
  
      function touchmoved() {
        var touches = exports.event.changedTouches,
            n = touches.length, i, gesture;
  
        for (i = 0; i < n; ++i) {
          if (gesture = gestures[touches[i].identifier]) {
            noevent();
            gesture("drag");
          }
        }
      }
  
      function touchended() {
        var touches = exports.event.changedTouches,
            n = touches.length, i, gesture;
  
        if (touchending) clearTimeout(touchending);
        touchending = setTimeout(function() { touchending = null; }, 500); // Ghost clicks are delayed!
        for (i = 0; i < n; ++i) {
          if (gesture = gestures[touches[i].identifier]) {
            nopropagation();
            gesture("end");
          }
        }
      }
  
      function beforestart(id, container, point, that, args) {
        var p = point(container, id), s, dx, dy,
            sublisteners = listeners.copy();
  
        if (!customEvent(new DragEvent(drag, "beforestart", s, id, active, p[0], p[1], 0, 0, sublisteners), function() {
          if ((exports.event.subject = s = subject.apply(that, args)) == null) return false;
          dx = s.x - p[0] || 0;
          dy = s.y - p[1] || 0;
          return true;
        })) return;
  
        return function gesture(type) {
          var p0 = p, n;
          switch (type) {
            case "start": gestures[id] = gesture, n = active++; break;
            case "end": delete gestures[id], --active; // nobreak
            case "drag": p = point(container, id), n = active; break;
          }
          customEvent(new DragEvent(drag, type, s, id, n, p[0] + dx, p[1] + dy, p[0] - p0[0], p[1] - p0[1], sublisteners), sublisteners.apply, sublisteners, [type, that, args]);
        };
      }
  
      drag.filter = function(_) {
        return arguments.length ? (filter = typeof _ === "function" ? _ : constant$7(!!_), drag) : filter;
      };
  
      drag.container = function(_) {
        return arguments.length ? (container = typeof _ === "function" ? _ : constant$7(_), drag) : container;
      };
  
      drag.subject = function(_) {
        return arguments.length ? (subject = typeof _ === "function" ? _ : constant$7(_), drag) : subject;
      };
  
      drag.on = function() {
        var value = listeners.on.apply(listeners, arguments);
        return value === listeners ? drag : value;
      };
  
      return drag;
    }
  
    function constant$8(x) {
      return function() {
        return x;
      };
    }
  
    function x$4(d) {
      return d[0];
    }
  
    function y$4(d) {
      return d[1];
    }
  
    function RedBlackTree() {
      this._ = null; // root node
    }
  
    function RedBlackNode(node) {
      node.U = // parent node
      node.C = // color - true for red, false for black
      node.L = // left node
      node.R = // right node
      node.P = // previous node
      node.N = null; // next node
    }
  
    RedBlackTree.prototype = {
      constructor: RedBlackTree,
  
      insert: function(after, node) {
        var parent, grandpa, uncle;
  
        if (after) {
          node.P = after;
          node.N = after.N;
          if (after.N) after.N.P = node;
          after.N = node;
          if (after.R) {
            after = after.R;
            while (after.L) after = after.L;
            after.L = node;
          } else {
            after.R = node;
          }
          parent = after;
        } else if (this._) {
          after = RedBlackFirst(this._);
          node.P = null;
          node.N = after;
          after.P = after.L = node;
          parent = after;
        } else {
          node.P = node.N = null;
          this._ = node;
          parent = null;
        }
        node.L = node.R = null;
        node.U = parent;
        node.C = true;
  
        after = node;
        while (parent && parent.C) {
          grandpa = parent.U;
          if (parent === grandpa.L) {
            uncle = grandpa.R;
            if (uncle && uncle.C) {
              parent.C = uncle.C = false;
              grandpa.C = true;
              after = grandpa;
            } else {
              if (after === parent.R) {
                RedBlackRotateLeft(this, parent);
                after = parent;
                parent = after.U;
              }
              parent.C = false;
              grandpa.C = true;
              RedBlackRotateRight(this, grandpa);
            }
          } else {
            uncle = grandpa.L;
            if (uncle && uncle.C) {
              parent.C = uncle.C = false;
              grandpa.C = true;
              after = grandpa;
            } else {
              if (after === parent.L) {
                RedBlackRotateRight(this, parent);
                after = parent;
                parent = after.U;
              }
              parent.C = false;
              grandpa.C = true;
              RedBlackRotateLeft(this, grandpa);
            }
          }
          parent = after.U;
        }
        this._.C = false;
      },
  
      remove: function(node) {
        if (node.N) node.N.P = node.P;
        if (node.P) node.P.N = node.N;
        node.N = node.P = null;
  
        var parent = node.U,
            sibling,
            left = node.L,
            right = node.R,
            next,
            red;
  
        if (!left) next = right;
        else if (!right) next = left;
        else next = RedBlackFirst(right);
  
        if (parent) {
          if (parent.L === node) parent.L = next;
          else parent.R = next;
        } else {
          this._ = next;
        }
  
        if (left && right) {
          red = next.C;
          next.C = node.C;
          next.L = left;
          left.U = next;
          if (next !== right) {
            parent = next.U;
            next.U = node.U;
            node = next.R;
            parent.L = node;
            next.R = right;
            right.U = next;
          } else {
            next.U = parent;
            parent = next;
            node = next.R;
          }
        } else {
          red = node.C;
          node = next;
        }
  
        if (node) node.U = parent;
        if (red) return;
        if (node && node.C) { node.C = false; return; }
  
        do {
          if (node === this._) break;
          if (node === parent.L) {
            sibling = parent.R;
            if (sibling.C) {
              sibling.C = false;
              parent.C = true;
              RedBlackRotateLeft(this, parent);
              sibling = parent.R;
            }
            if ((sibling.L && sibling.L.C)
                || (sibling.R && sibling.R.C)) {
              if (!sibling.R || !sibling.R.C) {
                sibling.L.C = false;
                sibling.C = true;
                RedBlackRotateRight(this, sibling);
                sibling = parent.R;
              }
              sibling.C = parent.C;
              parent.C = sibling.R.C = false;
              RedBlackRotateLeft(this, parent);
              node = this._;
              break;
            }
          } else {
            sibling = parent.L;
            if (sibling.C) {
              sibling.C = false;
              parent.C = true;
              RedBlackRotateRight(this, parent);
              sibling = parent.L;
            }
            if ((sibling.L && sibling.L.C)
              || (sibling.R && sibling.R.C)) {
              if (!sibling.L || !sibling.L.C) {
                sibling.R.C = false;
                sibling.C = true;
                RedBlackRotateLeft(this, sibling);
                sibling = parent.L;
              }
              sibling.C = parent.C;
              parent.C = sibling.L.C = false;
              RedBlackRotateRight(this, parent);
              node = this._;
              break;
            }
          }
          sibling.C = true;
          node = parent;
          parent = parent.U;
        } while (!node.C);
  
        if (node) node.C = false;
      }
    };
  
    function RedBlackRotateLeft(tree, node) {
      var p = node,
          q = node.R,
          parent = p.U;
  
      if (parent) {
        if (parent.L === p) parent.L = q;
        else parent.R = q;
      } else {
        tree._ = q;
      }
  
      q.U = parent;
      p.U = q;
      p.R = q.L;
      if (p.R) p.R.U = p;
      q.L = p;
    }
  
    function RedBlackRotateRight(tree, node) {
      var p = node,
          q = node.L,
          parent = p.U;
  
      if (parent) {
        if (parent.L === p) parent.L = q;
        else parent.R = q;
      } else {
        tree._ = q;
      }
  
      q.U = parent;
      p.U = q;
      p.L = q.R;
      if (p.L) p.L.U = p;
      q.R = p;
    }
  
    function RedBlackFirst(node) {
      while (node.L) node = node.L;
      return node;
    }
  
    function createEdge(left, right, v0, v1) {
      var edge = [null, null],
          index = edges.push(edge) - 1;
      edge.left = left;
      edge.right = right;
      if (v0) setEdgeEnd(edge, left, right, v0);
      if (v1) setEdgeEnd(edge, right, left, v1);
      cells[left.index].halfedges.push(index);
      cells[right.index].halfedges.push(index);
      return edge;
    }
  
    function createBorderEdge(left, v0, v1) {
      var edge = [v0, v1];
      edge.left = left;
      return edge;
    }
  
    function setEdgeEnd(edge, left, right, vertex) {
      if (!edge[0] && !edge[1]) {
        edge[0] = vertex;
        edge.left = left;
        edge.right = right;
      } else if (edge.left === right) {
        edge[1] = vertex;
      } else {
        edge[0] = vertex;
      }
    }
  
    // Liang–Barsky line clipping.
    function clipEdge(edge, x0, y0, x1, y1) {
      var a = edge[0],
          b = edge[1],
          ax = a[0],
          ay = a[1],
          bx = b[0],
          by = b[1],
          t0 = 0,
          t1 = 1,
          dx = bx - ax,
          dy = by - ay,
          r;
  
      r = x0 - ax;
      if (!dx && r > 0) return;
      r /= dx;
      if (dx < 0) {
        if (r < t0) return;
        if (r < t1) t1 = r;
      } else if (dx > 0) {
        if (r > t1) return;
        if (r > t0) t0 = r;
      }
  
      r = x1 - ax;
      if (!dx && r < 0) return;
      r /= dx;
      if (dx < 0) {
        if (r > t1) return;
        if (r > t0) t0 = r;
      } else if (dx > 0) {
        if (r < t0) return;
        if (r < t1) t1 = r;
      }
  
      r = y0 - ay;
      if (!dy && r > 0) return;
      r /= dy;
      if (dy < 0) {
        if (r < t0) return;
        if (r < t1) t1 = r;
      } else if (dy > 0) {
        if (r > t1) return;
        if (r > t0) t0 = r;
      }
  
      r = y1 - ay;
      if (!dy && r < 0) return;
      r /= dy;
      if (dy < 0) {
        if (r > t1) return;
        if (r > t0) t0 = r;
      } else if (dy > 0) {
        if (r < t0) return;
        if (r < t1) t1 = r;
      }
  
      if (!(t0 > 0) && !(t1 < 1)) return true; // TODO Better check?
  
      if (t0 > 0) edge[0] = [ax + t0 * dx, ay + t0 * dy];
      if (t1 < 1) edge[1] = [ax + t1 * dx, ay + t1 * dy];
      return true;
    }
  
    function connectEdge(edge, x0, y0, x1, y1) {
      var v1 = edge[1];
      if (v1) return true;
  
      var v0 = edge[0],
          left = edge.left,
          right = edge.right,
          lx = left[0],
          ly = left[1],
          rx = right[0],
          ry = right[1],
          fx = (lx + rx) / 2,
          fy = (ly + ry) / 2,
          fm,
          fb;
  
      if (ry === ly) {
        if (fx < x0 || fx >= x1) return;
        if (lx > rx) {
          if (!v0) v0 = [fx, y0];
          else if (v0[1] >= y1) return;
          v1 = [fx, y1];
        } else {
          if (!v0) v0 = [fx, y1];
          else if (v0[1] < y0) return;
          v1 = [fx, y0];
        }
      } else {
        fm = (lx - rx) / (ry - ly);
        fb = fy - fm * fx;
        if (fm < -1 || fm > 1) {
          if (lx > rx) {
            if (!v0) v0 = [(y0 - fb) / fm, y0];
            else if (v0[1] >= y1) return;
            v1 = [(y1 - fb) / fm, y1];
          } else {
            if (!v0) v0 = [(y1 - fb) / fm, y1];
            else if (v0[1] < y0) return;
            v1 = [(y0 - fb) / fm, y0];
          }
        } else {
          if (ly < ry) {
            if (!v0) v0 = [x0, fm * x0 + fb];
            else if (v0[0] >= x1) return;
            v1 = [x1, fm * x1 + fb];
          } else {
            if (!v0) v0 = [x1, fm * x1 + fb];
            else if (v0[0] < x0) return;
            v1 = [x0, fm * x0 + fb];
          }
        }
      }
  
      edge[0] = v0;
      edge[1] = v1;
      return true;
    }
  
    function clipEdges(x0, y0, x1, y1) {
      var i = edges.length,
          edge;
  
      while (i--) {
        if (!connectEdge(edge = edges[i], x0, y0, x1, y1)
            || !clipEdge(edge, x0, y0, x1, y1)
            || !(Math.abs(edge[0][0] - edge[1][0]) > epsilon$3
                || Math.abs(edge[0][1] - edge[1][1]) > epsilon$3)) {
          delete edges[i];
        }
      }
    }
  
    function createCell(site) {
      return cells[site.index] = {
        site: site,
        halfedges: []
      };
    }
  
    function cellHalfedgeAngle(cell, edge) {
      var site = cell.site,
          va = edge.left,
          vb = edge.right;
      if (site === vb) vb = va, va = site;
      if (vb) return Math.atan2(vb[1] - va[1], vb[0] - va[0]);
      if (site === va) va = edge[1], vb = edge[0];
      else va = edge[0], vb = edge[1];
      return Math.atan2(va[0] - vb[0], vb[1] - va[1]);
    }
  
    function cellHalfedgeStart(cell, edge) {
      return edge[+(edge.left !== cell.site)];
    }
  
    function cellHalfedgeEnd(cell, edge) {
      return edge[+(edge.left === cell.site)];
    }
  
    function sortCellHalfedges() {
      for (var i = 0, n = cells.length, cell, halfedges, j, m; i < n; ++i) {
        if ((cell = cells[i]) && (m = (halfedges = cell.halfedges).length)) {
          var index = new Array(m),
              array = new Array(m);
          for (j = 0; j < m; ++j) index[j] = j, array[j] = cellHalfedgeAngle(cell, edges[halfedges[j]]);
          index.sort(function(i, j) { return array[j] - array[i]; });
          for (j = 0; j < m; ++j) array[j] = halfedges[index[j]];
          for (j = 0; j < m; ++j) halfedges[j] = array[j];
        }
      }
    }
  
    function clipCells(x0, y0, x1, y1) {
      var nCells = cells.length,
          iCell,
          cell,
          site,
          iHalfedge,
          halfedges,
          nHalfedges,
          start,
          startX,
          startY,
          end,
          endX,
          endY,
          cover = true;
  
      for (iCell = 0; iCell < nCells; ++iCell) {
        if (cell = cells[iCell]) {
          site = cell.site;
          halfedges = cell.halfedges;
          iHalfedge = halfedges.length;
  
          // Remove any dangling clipped edges.
          while (iHalfedge--) {
            if (!edges[halfedges[iHalfedge]]) {
              halfedges.splice(iHalfedge, 1);
            }
          }
  
          // Insert any border edges as necessary.
          iHalfedge = 0, nHalfedges = halfedges.length;
          while (iHalfedge < nHalfedges) {
            end = cellHalfedgeEnd(cell, edges[halfedges[iHalfedge]]), endX = end[0], endY = end[1];
            start = cellHalfedgeStart(cell, edges[halfedges[++iHalfedge % nHalfedges]]), startX = start[0], startY = start[1];
            if (Math.abs(endX - startX) > epsilon$3 || Math.abs(endY - startY) > epsilon$3) {
              halfedges.splice(iHalfedge, 0, edges.push(createBorderEdge(site, end,
                  Math.abs(endX - x0) < epsilon$3 && y1 - endY > epsilon$3 ? [x0, Math.abs(startX - x0) < epsilon$3 ? startY : y1]
                  : Math.abs(endY - y1) < epsilon$3 && x1 - endX > epsilon$3 ? [Math.abs(startY - y1) < epsilon$3 ? startX : x1, y1]
                  : Math.abs(endX - x1) < epsilon$3 && endY - y0 > epsilon$3 ? [x1, Math.abs(startX - x1) < epsilon$3 ? startY : y0]
                  : Math.abs(endY - y0) < epsilon$3 && endX - x0 > epsilon$3 ? [Math.abs(startY - y0) < epsilon$3 ? startX : x0, y0]
                  : null)) - 1);
              ++nHalfedges;
            }
          }
  
          if (nHalfedges) cover = false;
        }
      }
  
      // If there weren’t any edges, have the closest site cover the extent.
      // It doesn’t matter which corner of the extent we measure!
      if (cover) {
        var dx, dy, d2, dc = Infinity;
  
        for (iCell = 0, cover = null; iCell < nCells; ++iCell) {
          if (cell = cells[iCell]) {
            site = cell.site;
            dx = site[0] - x0;
            dy = site[1] - y0;
            d2 = dx * dx + dy * dy;
            if (d2 < dc) dc = d2, cover = cell;
          }
        }
  
        if (cover) {
          var v00 = [x0, y0], v01 = [x0, y1], v11 = [x1, y1], v10 = [x1, y0];
          cover.halfedges.push(
            edges.push(createBorderEdge(site = cover.site, v00, v01)) - 1,
            edges.push(createBorderEdge(site, v01, v11)) - 1,
            edges.push(createBorderEdge(site, v11, v10)) - 1,
            edges.push(createBorderEdge(site, v10, v00)) - 1
          );
        }
      }
  
      // Lastly delete any cells with no edges; these were entirely clipped.
      for (iCell = 0; iCell < nCells; ++iCell) {
        if (cell = cells[iCell]) {
          if (!cell.halfedges.length) {
            delete cells[iCell];
          }
        }
      }
    }
  
    var circlePool = [];
  
    var firstCircle;
  
    function Circle() {
      RedBlackNode(this);
      this.x =
      this.y =
      this.arc =
      this.site =
      this.cy = null;
    }
  
    function attachCircle(arc) {
      var lArc = arc.P,
          rArc = arc.N;
  
      if (!lArc || !rArc) return;
  
      var lSite = lArc.site,
          cSite = arc.site,
          rSite = rArc.site;
  
      if (lSite === rSite) return;
  
      var bx = cSite[0],
          by = cSite[1],
          ax = lSite[0] - bx,
          ay = lSite[1] - by,
          cx = rSite[0] - bx,
          cy = rSite[1] - by;
  
      var d = 2 * (ax * cy - ay * cx);
      if (d >= -epsilon2$1) return;
  
      var ha = ax * ax + ay * ay,
          hc = cx * cx + cy * cy,
          x = (cy * ha - ay * hc) / d,
          y = (ax * hc - cx * ha) / d;
  
      var circle = circlePool.pop() || new Circle;
      circle.arc = arc;
      circle.site = cSite;
      circle.x = x + bx;
      circle.y = (circle.cy = y + by) + Math.sqrt(x * x + y * y); // y bottom
  
      arc.circle = circle;
  
      var before = null,
          node = circles._;
  
      while (node) {
        if (circle.y < node.y || (circle.y === node.y && circle.x <= node.x)) {
          if (node.L) node = node.L;
          else { before = node.P; break; }
        } else {
          if (node.R) node = node.R;
          else { before = node; break; }
        }
      }
  
      circles.insert(before, circle);
      if (!before) firstCircle = circle;
    }
  
    function detachCircle(arc) {
      var circle = arc.circle;
      if (circle) {
        if (!circle.P) firstCircle = circle.N;
        circles.remove(circle);
        circlePool.push(circle);
        RedBlackNode(circle);
        arc.circle = null;
      }
    }
  
    var beachPool = [];
  
    function Beach() {
      RedBlackNode(this);
      this.edge =
      this.site =
      this.circle = null;
    }
  
    function createBeach(site) {
      var beach = beachPool.pop() || new Beach;
      beach.site = site;
      return beach;
    }
  
    function detachBeach(beach) {
      detachCircle(beach);
      beaches.remove(beach);
      beachPool.push(beach);
      RedBlackNode(beach);
    }
  
    function removeBeach(beach) {
      var circle = beach.circle,
          x = circle.x,
          y = circle.cy,
          vertex = [x, y],
          previous = beach.P,
          next = beach.N,
          disappearing = [beach];
  
      detachBeach(beach);
  
      var lArc = previous;
      while (lArc.circle
          && Math.abs(x - lArc.circle.x) < epsilon$3
          && Math.abs(y - lArc.circle.cy) < epsilon$3) {
        previous = lArc.P;
        disappearing.unshift(lArc);
        detachBeach(lArc);
        lArc = previous;
      }
  
      disappearing.unshift(lArc);
      detachCircle(lArc);
  
      var rArc = next;
      while (rArc.circle
          && Math.abs(x - rArc.circle.x) < epsilon$3
          && Math.abs(y - rArc.circle.cy) < epsilon$3) {
        next = rArc.N;
        disappearing.push(rArc);
        detachBeach(rArc);
        rArc = next;
      }
  
      disappearing.push(rArc);
      detachCircle(rArc);
  
      var nArcs = disappearing.length,
          iArc;
      for (iArc = 1; iArc < nArcs; ++iArc) {
        rArc = disappearing[iArc];
        lArc = disappearing[iArc - 1];
        setEdgeEnd(rArc.edge, lArc.site, rArc.site, vertex);
      }
  
      lArc = disappearing[0];
      rArc = disappearing[nArcs - 1];
      rArc.edge = createEdge(lArc.site, rArc.site, null, vertex);
  
      attachCircle(lArc);
      attachCircle(rArc);
    }
  
    function addBeach(site) {
      var x = site[0],
          directrix = site[1],
          lArc,
          rArc,
          dxl,
          dxr,
          node = beaches._;
  
      while (node) {
        dxl = leftBreakPoint(node, directrix) - x;
        if (dxl > epsilon$3) node = node.L; else {
          dxr = x - rightBreakPoint(node, directrix);
          if (dxr > epsilon$3) {
            if (!node.R) {
              lArc = node;
              break;
            }
            node = node.R;
          } else {
            if (dxl > -epsilon$3) {
              lArc = node.P;
              rArc = node;
            } else if (dxr > -epsilon$3) {
              lArc = node;
              rArc = node.N;
            } else {
              lArc = rArc = node;
            }
            break;
          }
        }
      }
  
      createCell(site);
      var newArc = createBeach(site);
      beaches.insert(lArc, newArc);
  
      if (!lArc && !rArc) return;
  
      if (lArc === rArc) {
        detachCircle(lArc);
        rArc = createBeach(lArc.site);
        beaches.insert(newArc, rArc);
        newArc.edge = rArc.edge = createEdge(lArc.site, newArc.site);
        attachCircle(lArc);
        attachCircle(rArc);
        return;
      }
  
      if (!rArc) { // && lArc
        newArc.edge = createEdge(lArc.site, newArc.site);
        return;
      }
  
      // else lArc !== rArc
      detachCircle(lArc);
      detachCircle(rArc);
  
      var lSite = lArc.site,
          ax = lSite[0],
          ay = lSite[1],
          bx = site[0] - ax,
          by = site[1] - ay,
          rSite = rArc.site,
          cx = rSite[0] - ax,
          cy = rSite[1] - ay,
          d = 2 * (bx * cy - by * cx),
          hb = bx * bx + by * by,
          hc = cx * cx + cy * cy,
          vertex = [(cy * hb - by * hc) / d + ax, (bx * hc - cx * hb) / d + ay];
  
      setEdgeEnd(rArc.edge, lSite, rSite, vertex);
      newArc.edge = createEdge(lSite, site, null, vertex);
      rArc.edge = createEdge(site, rSite, null, vertex);
      attachCircle(lArc);
      attachCircle(rArc);
    }
  
    function leftBreakPoint(arc, directrix) {
      var site = arc.site,
          rfocx = site[0],
          rfocy = site[1],
          pby2 = rfocy - directrix;
  
      if (!pby2) return rfocx;
  
      var lArc = arc.P;
      if (!lArc) return -Infinity;
  
      site = lArc.site;
      var lfocx = site[0],
          lfocy = site[1],
          plby2 = lfocy - directrix;
  
      if (!plby2) return lfocx;
  
      var hl = lfocx - rfocx,
          aby2 = 1 / pby2 - 1 / plby2,
          b = hl / plby2;
  
      if (aby2) return (-b + Math.sqrt(b * b - 2 * aby2 * (hl * hl / (-2 * plby2) - lfocy + plby2 / 2 + rfocy - pby2 / 2))) / aby2 + rfocx;
  
      return (rfocx + lfocx) / 2;
    }
  
    function rightBreakPoint(arc, directrix) {
      var rArc = arc.N;
      if (rArc) return leftBreakPoint(rArc, directrix);
      var site = arc.site;
      return site[1] === directrix ? site[0] : Infinity;
    }
  
    var epsilon$3 = 1e-6;
    var epsilon2$1 = 1e-12;
    var beaches;
    var cells;
    var circles;
    var edges;
  
    function triangleArea(a, b, c) {
      return (a[0] - c[0]) * (b[1] - a[1]) - (a[0] - b[0]) * (c[1] - a[1]);
    }
  
    function lexicographic(a, b) {
      return b[1] - a[1]
          || b[0] - a[0];
    }
  
    function Diagram(sites, extent) {
      var site = sites.sort(lexicographic).pop(),
          x,
          y,
          circle;
  
      edges = [];
      cells = new Array(sites.length);
      beaches = new RedBlackTree;
      circles = new RedBlackTree;
  
      while (true) {
        circle = firstCircle;
        if (site && (!circle || site[1] < circle.y || (site[1] === circle.y && site[0] < circle.x))) {
          if (site[0] !== x || site[1] !== y) {
            addBeach(site);
            x = site[0], y = site[1];
          }
          site = sites.pop();
        } else if (circle) {
          removeBeach(circle.arc);
        } else {
          break;
        }
      }
  
      sortCellHalfedges();
  
      if (extent) {
        var x0 = +extent[0][0],
            y0 = +extent[0][1],
            x1 = +extent[1][0],
            y1 = +extent[1][1];
        clipEdges(x0, y0, x1, y1);
        clipCells(x0, y0, x1, y1);
      }
  
      this.edges = edges;
      this.cells = cells;
  
      beaches =
      circles =
      edges =
      cells = null;
    }
  
    Diagram.prototype = {
      constructor: Diagram,
  
      polygons: function() {
        var edges = this.edges;
  
        return this.cells.map(function(cell) {
          var polygon = cell.halfedges.map(function(i) { return cellHalfedgeStart(cell, edges[i]); });
          polygon.data = cell.site.data;
          return polygon;
        });
      },
  
      triangles: function() {
        var triangles = [],
            edges = this.edges;
  
        this.cells.forEach(function(cell, i) {
          var site = cell.site,
              halfedges = cell.halfedges,
              j = -1,
              m = halfedges.length,
              s0,
              e1 = edges[halfedges[m - 1]],
              s1 = e1.left === site ? e1.right : e1.left;
  
          while (++j < m) {
            s0 = s1;
            e1 = edges[halfedges[j]];
            s1 = e1.left === site ? e1.right : e1.left;
            if (i < s0.index && i < s1.index && triangleArea(site, s0, s1) < 0) {
              triangles.push([site.data, s0.data, s1.data]);
            }
          }
        });
  
        return triangles;
      },
  
      links: function() {
        return this.edges.filter(function(edge) {
          return edge.right;
        }).map(function(edge) {
          return {
            source: edge.left.data,
            target: edge.right.data
          };
        });
      }
    }
  
    function voronoi() {
      var x = x$4,
          y = y$4,
          extent = null;
  
      function voronoi(data) {
        return new Diagram(data.map(function(d, i) {
          var s = [Math.round(x(d, i, data) / epsilon$3) * epsilon$3, Math.round(y(d, i, data) / epsilon$3) * epsilon$3];
          s.index = i;
          s.data = d;
          return s;
        }), extent);
      }
  
      voronoi.polygons = function(data) {
        return voronoi(data).polygons();
      };
  
      voronoi.links = function(data) {
        return voronoi(data).links();
      };
  
      voronoi.triangles = function(data) {
        return voronoi(data).triangles();
      };
  
      voronoi.x = function(_) {
        return arguments.length ? (x = typeof _ === "function" ? _ : constant$8(+_), voronoi) : x;
      };
  
      voronoi.y = function(_) {
        return arguments.length ? (y = typeof _ === "function" ? _ : constant$8(+_), voronoi) : y;
      };
  
      voronoi.extent = function(_) {
        return arguments.length ? (extent = _ == null ? null : [[+_[0][0], +_[0][1]], [+_[1][0], +_[1][1]]], voronoi) : extent && [[extent[0][0], extent[0][1]], [extent[1][0], extent[1][1]]];
      };
  
      voronoi.size = function(_) {
        return arguments.length ? (extent = _ == null ? null : [[0, 0], [+_[0], +_[1]]], voronoi) : extent && [extent[1][0] - extent[0][0], extent[1][1] - extent[0][1]];
      };
  
      return voronoi;
    }
  
    function constant$9(x) {
      return function() {
        return x;
      };
    }
  
    function ZoomEvent(target, type, transform) {
      this.target = target;
      this.type = type;
      this.transform = transform;
    }
  
    function Transform(k, x, y) {
      this.k = k;
      this.x = x;
      this.y = y;
    }
  
    Transform.prototype = {
      constructor: Transform,
      scale: function(k) {
        return k === 1 ? this : new Transform(this.k * k, this.x, this.y);
      },
      translate: function(x, y) {
        return x === 0 & y === 0 ? this : new Transform(this.k, this.x + this.k * x, this.y + this.k * y);
      },
      apply: function(point) {
        return [point[0] * this.k + this.x, point[1] * this.k + this.y];
      },
      applyX: function(x) {
        return x * this.k + this.x;
      },
      applyY: function(y) {
        return y * this.k + this.y;
      },
      invert: function(location) {
        return [(location[0] - this.x) / this.k, (location[1] - this.y) / this.k];
      },
      invertX: function(x) {
        return (x - this.x) / this.k;
      },
      invertY: function(y) {
        return (y - this.y) / this.k;
      },
      rescaleX: function(x) {
        return x.copy().domain(x.range().map(this.invertX, this).map(x.invert, x));
      },
      rescaleY: function(y) {
        return y.copy().domain(y.range().map(this.invertY, this).map(y.invert, y));
      },
      toString: function() {
        return "translate(" + this.x + "," + this.y + ") scale(" + this.k + ")";
      }
    };
  
    var identity$6 = new Transform(1, 0, 0);
  
    transform.prototype = Transform.prototype;
  
    function transform(node) {
      return node.__zoom || identity$6;
    }
  
    function nopropagation$1() {
      exports.event.stopImmediatePropagation();
    }
  
    function noevent$1() {
      exports.event.preventDefault();
      exports.event.stopImmediatePropagation();
    }
  
    // Ignore right-click, since that should open the context menu.
    function defaultFilter$1() {
      return !exports.event.button;
    }
  
    function defaultExtent() {
      var e = this, w, h;
      if (e instanceof SVGElement) {
        e = e.ownerSVGElement || e;
        w = e.width.baseVal.value;
        h = e.height.baseVal.value;
      } else {
        w = e.clientWidth;
        h = e.clientHeight;
      }
      return [[0, 0], [w, h]];
    }
  
    function defaultTransform() {
      return this.__zoom || identity$6;
    }
  
    function zoom() {
      var filter = defaultFilter$1,
          extent = defaultExtent,
          k0 = 0,
          k1 = Infinity,
          x0 = -k1,
          x1 = k1,
          y0 = x0,
          y1 = x1,
          duration = 250,
          gestures = [],
          listeners = dispatch("start", "zoom", "end"),
          touchstarting,
          touchending,
          touchDelay = 500,
          wheelDelay = 150;
  
      function zoom(selection) {
        selection
            .on("wheel.zoom", wheeled)
            .on("mousedown.zoom", mousedowned)
            .on("dblclick.zoom", dblclicked)
            .on("touchstart.zoom", touchstarted)
            .on("touchmove.zoom", touchmoved)
            .on("touchend.zoom touchcancel.zoom", touchended)
            .style("-webkit-tap-highlight-color", "rgba(0,0,0,0)")
            .property("__zoom", defaultTransform);
      }
  
      zoom.transform = function(collection, transform) {
        var selection = collection.selection ? collection.selection() : collection;
        selection.property("__zoom", defaultTransform);
        if (collection !== selection) {
          schedule(collection, transform);
        } else {
          selection.interrupt().each(function() {
            gesture(this, arguments)
                .start()
                .zoom(null, typeof transform === "function" ? transform.apply(this, arguments) : transform)
                .end();
          });
        }
      };
  
      zoom.scaleBy = function(selection, k) {
        zoom.scaleTo(selection, function() {
          var k0 = this.__zoom.k,
              k1 = typeof k === "function" ? k.apply(this, arguments) : k;
          return k0 * k1;
        });
      };
  
      zoom.scaleTo = function(selection, k) {
        zoom.transform(selection, function() {
          var e = extent.apply(this, arguments),
              t0 = this.__zoom,
              p0 = centroid(e),
              p1 = t0.invert(p0),
              k1 = typeof k === "function" ? k.apply(this, arguments) : k;
          return constrain(translate(scale(t0, k1), p0, p1), e);
        });
      };
  
      zoom.translateBy = function(selection, x, y) {
        zoom.transform(selection, function() {
          return constrain(this.__zoom.translate(
            typeof x === "function" ? x.apply(this, arguments) : x,
            typeof y === "function" ? y.apply(this, arguments) : y
          ), extent.apply(this, arguments));
        });
      };
  
      function scale(transform, k) {
        k = Math.max(k0, Math.min(k1, k));
        return k === transform.k ? transform : new Transform(k, transform.x, transform.y);
      }
  
      function translate(transform, p0, p1) {
        var x = p0[0] - p1[0] * transform.k, y = p0[1] - p1[1] * transform.k;
        return x === transform.x && y === transform.y ? transform : new Transform(transform.k, x, y);
      }
  
      function constrain(transform, extent) {
        var dx = Math.min(0, transform.invertX(extent[0][0]) - x0) || Math.max(0, transform.invertX(extent[1][0]) - x1),
            dy = Math.min(0, transform.invertY(extent[0][1]) - y0) || Math.max(0, transform.invertY(extent[1][1]) - y1);
        return dx || dy ? transform.translate(dx, dy) : transform;
      }
  
      function centroid(extent) {
        return [(+extent[0][0] + +extent[1][0]) / 2, (+extent[0][1] + +extent[1][1]) / 2];
      }
  
      function schedule(transition, transform, center) {
        transition
            .on("start.zoom", function() { gesture(this, arguments).start(); })
            .on("interrupt.zoom end.zoom", function() { gesture(this, arguments).end(); })
            .tween("zoom", function() {
              var that = this,
                  args = arguments,
                  g = gesture(that, args),
                  e = extent.apply(that, args),
                  p = center || centroid(e),
                  w = Math.max(e[1][0] - e[0][0], e[1][1] - e[0][1]),
                  a = that.__zoom,
                  b = typeof transform === "function" ? transform.apply(that, args) : transform,
                  i = interpolateZoom(a.invert(p).concat(w / a.k), b.invert(p).concat(w / b.k));
              return function(t) {
                if (t === 1) t = b; // Avoid rounding error on end.
                else { var l = i(t), k = w / l[2]; t = new Transform(k, p[0] - l[0] * k, p[1] - l[1] * k); }
                g.zoom(null, t);
              };
            });
      }
  
      function gesture(that, args) {
        for (var i = 0, n = gestures.length, g; i < n; ++i) {
          if ((g = gestures[i]).that === that) {
            return g;
          }
        }
        return new Gesture(that, args);
      }
  
      function Gesture(that, args) {
        this.that = that;
        this.args = args;
        this.index = -1;
        this.active = 0;
        this.extent = extent.apply(that, args);
      }
  
      Gesture.prototype = {
        start: function() {
          if (++this.active === 1) {
            this.index = gestures.push(this) - 1;
            this.emit("start");
          }
          return this;
        },
        zoom: function(key, transform) {
          if (this.mouse && key !== "mouse") this.mouse[1] = transform.invert(this.mouse[0]);
          if (this.touch0 && key !== "touch") this.touch0[1] = transform.invert(this.touch0[0]);
          if (this.touch1 && key !== "touch") this.touch1[1] = transform.invert(this.touch1[0]);
          this.that.__zoom = transform;
          this.emit("zoom");
          return this;
        },
        end: function() {
          if (--this.active === 0) {
            gestures.splice(this.index, 1);
            this.index = -1;
            this.emit("end");
          }
          return this;
        },
        emit: function(type) {
          customEvent(new ZoomEvent(zoom, type, this.that.__zoom), listeners.apply, listeners, [type, this.that, this.args]);
        }
      };
  
      function wheeled() {
        if (!filter.apply(this, arguments)) return;
        var g = gesture(this, arguments),
            t = this.__zoom,
            k = Math.max(k0, Math.min(k1, t.k * Math.pow(2, -exports.event.deltaY * (exports.event.deltaMode ? 120 : 1) / 500))),
            p = mouse(this);
  
        // If the mouse is in the same location as before, reuse it.
        // If there were recent wheel events, reset the wheel idle timeout.
        if (g.wheel) {
          if (g.mouse[0][0] !== p[0] || g.mouse[0][1] !== p[1]) {
            g.mouse[1] = t.invert(g.mouse[0] = p);
          }
          clearTimeout(g.wheel);
        }
  
        // If this wheel event won’t trigger a transform change, ignore it.
        else if (t.k === k) return;
  
        // Otherwise, capture the mouse point and location at the start.
        else {
          g.mouse = [p, t.invert(p)];
          interrupt(this);
          g.start();
        }
  
        noevent$1();
        g.wheel = setTimeout(wheelidled, wheelDelay);
        g.zoom("mouse", constrain(translate(scale(t, k), g.mouse[0], g.mouse[1]), g.extent));
  
        function wheelidled() {
          g.wheel = null;
          g.end();
        }
      }
  
      function mousedowned() {
        if (touchending || !filter.apply(this, arguments)) return;
        var g = gesture(this, arguments),
            v = select(exports.event.view).on("mousemove.zoom", mousemoved, true).on("mouseup.zoom", mouseupped, true),
            p = mouse(this);
  
        dragDisable(exports.event.view);
        nopropagation$1();
        g.mouse = [p, this.__zoom.invert(p)];
        interrupt(this);
        g.start();
  
        function mousemoved() {
          noevent$1();
          g.moved = true;
          g.zoom("mouse", constrain(translate(g.that.__zoom, g.mouse[0] = mouse(g.that), g.mouse[1]), g.extent));
        }
  
        function mouseupped() {
          v.on("mousemove.zoom mouseup.zoom", null);
          dragEnable(exports.event.view, g.moved);
          noevent$1();
          g.end();
        }
      }
  
      function dblclicked() {
        if (!filter.apply(this, arguments)) return;
        var t0 = this.__zoom,
            p0 = mouse(this),
            p1 = t0.invert(p0),
            k1 = t0.k * (exports.event.shiftKey ? 0.5 : 2),
            t1 = constrain(translate(scale(t0, k1), p0, p1), extent.apply(this, arguments));
  
        noevent$1();
        if (duration > 0) select(this).transition().duration(duration).call(schedule, t1, p0);
        else select(this).call(zoom.transform, t1);
      }
  
      function touchstarted() {
        if (!filter.apply(this, arguments)) return;
        var g = gesture(this, arguments),
            touches = exports.event.changedTouches,
            n = touches.length, i, t, p;
  
        nopropagation$1();
        for (i = 0; i < n; ++i) {
          t = touches[i], p = touch(this, touches, t.identifier);
          p = [p, this.__zoom.invert(p), t.identifier];
          if (!g.touch0) g.touch0 = p;
          else if (!g.touch1) g.touch1 = p;
        }
        if (touchstarting) {
          touchstarting = clearTimeout(touchstarting);
          if (!g.touch1) return g.end(), dblclicked.apply(this, arguments);
        }
        if (exports.event.touches.length === n) {
          touchstarting = setTimeout(function() { touchstarting = null; }, touchDelay);
          interrupt(this);
          g.start();
        }
      }
  
      function touchmoved() {
        var g = gesture(this, arguments),
            touches = exports.event.changedTouches,
            n = touches.length, i, t, p, l;
  
        noevent$1();
        if (touchstarting) touchstarting = clearTimeout(touchstarting);
        for (i = 0; i < n; ++i) {
          t = touches[i], p = touch(this, touches, t.identifier);
          if (g.touch0 && g.touch0[2] === t.identifier) g.touch0[0] = p;
          else if (g.touch1 && g.touch1[2] === t.identifier) g.touch1[0] = p;
        }
        t = g.that.__zoom;
        if (g.touch1) {
          var p0 = g.touch0[0], l0 = g.touch0[1],
              p1 = g.touch1[0], l1 = g.touch1[1],
              dp = (dp = p1[0] - p0[0]) * dp + (dp = p1[1] - p0[1]) * dp,
              dl = (dl = l1[0] - l0[0]) * dl + (dl = l1[1] - l0[1]) * dl;
          t = scale(t, Math.sqrt(dp / dl));
          p = [(p0[0] + p1[0]) / 2, (p0[1] + p1[1]) / 2];
          l = [(l0[0] + l1[0]) / 2, (l0[1] + l1[1]) / 2];
        }
        else if (g.touch0) p = g.touch0[0], l = g.touch0[1];
        else return;
        g.zoom("touch", constrain(translate(t, p, l), g.extent));
      }
  
      function touchended() {
        var g = gesture(this, arguments),
            touches = exports.event.changedTouches,
            n = touches.length, i, t;
  
        nopropagation$1();
        if (touchending) clearTimeout(touchending);
        touchending = setTimeout(function() { touchending = null; }, touchDelay);
        for (i = 0; i < n; ++i) {
          t = touches[i];
          if (g.touch0 && g.touch0[2] === t.identifier) delete g.touch0;
          else if (g.touch1 && g.touch1[2] === t.identifier) delete g.touch1;
        }
        if (g.touch1 && !g.touch0) g.touch0 = g.touch1, delete g.touch1;
        if (!g.touch0) g.end();
      }
  
      zoom.filter = function(_) {
        return arguments.length ? (filter = typeof _ === "function" ? _ : constant$9(!!_), zoom) : filter;
      };
  
      zoom.extent = function(_) {
        return arguments.length ? (extent = typeof _ === "function" ? _ : constant$9([[+_[0][0], +_[0][1]], [+_[1][0], +_[1][1]]]), zoom) : extent;
      };
  
      zoom.scaleExtent = function(_) {
        return arguments.length ? (k0 = +_[0], k1 = +_[1], zoom) : [k0, k1];
      };
  
      zoom.translateExtent = function(_) {
        return arguments.length ? (x0 = +_[0][0], x1 = +_[1][0], y0 = +_[0][1], y1 = +_[1][1], zoom) : [[x0, y0], [x1, y1]];
      };
  
      zoom.duration = function(_) {
        return arguments.length ? (duration = +_, zoom) : duration;
      };
  
      zoom.on = function() {
        var value = listeners.on.apply(listeners, arguments);
        return value === listeners ? zoom : value;
      };
  
      return zoom;
    }
  
    function constant$10(x) {
      return function() {
        return x;
      };
    }
  
    function BrushEvent(target, type, selection) {
      this.target = target;
      this.type = type;
      this.selection = selection;
    }
  
    function nopropagation$2() {
      exports.event.stopImmediatePropagation();
    }
  
    function noevent$2() {
      exports.event.preventDefault();
      exports.event.stopImmediatePropagation();
    }
  
    var MODE_DRAG = {name: "drag"};
    var MODE_SPACE = {name: "space"};
    var MODE_HANDLE = {name: "handle"};
    var MODE_CENTER = {name: "center"};
    var X = {
      name: "x",
      handles: ["e", "w"].map(type$1),
      input: function(x, e) { return x && [[x[0], e[0][1]], [x[1], e[1][1]]]; },
      output: function(xy) { return xy && [xy[0][0], xy[1][0]]; }
    };
  
    var Y = {
      name: "y",
      handles: ["n", "s"].map(type$1),
      input: function(y, e) { return y && [[e[0][0], y[0]], [e[1][0], y[1]]]; },
      output: function(xy) { return xy && [xy[0][1], xy[1][1]]; }
    };
  
    var XY = {
      name: "xy",
      handles: ["n", "e", "s", "w", "nw", "ne", "se", "sw"].map(type$1),
      input: function(xy) { return xy; },
      output: function(xy) { return xy; }
    };
  
    var cursors = {
      overlay: "crosshair",
      selection: "move",
      n: "ns-resize",
      e: "ew-resize",
      s: "ns-resize",
      w: "ew-resize",
      nw: "nwse-resize",
      ne: "nesw-resize",
      se: "nwse-resize",
      sw: "nesw-resize"
    };
  
    var flipX = {
      e: "w",
      w: "e",
      nw: "ne",
      ne: "nw",
      se: "sw",
      sw: "se"
    };
  
    var flipY = {
      n: "s",
      s: "n",
      nw: "sw",
      ne: "se",
      se: "ne",
      sw: "nw"
    };
  
    var signsX = {
      overlay: +1,
      selection: +1,
      n: null,
      e: +1,
      s: null,
      w: -1,
      nw: -1,
      ne: +1,
      se: +1,
      sw: -1
    };
  
    var signsY = {
      overlay: +1,
      selection: +1,
      n: -1,
      e: null,
      s: +1,
      w: null,
      nw: -1,
      ne: -1,
      se: +1,
      sw: +1
    };
  
    function type$1(t) {
      return {type: t};
    }
  
    // Ignore right-click, since that should open the context menu.
    function defaultFilter$2() {
      return !exports.event.button;
    }
  
    function defaultExtent$1() {
      var svg = this.ownerSVGElement || this;
      return [[0, 0], [svg.width.baseVal.value, svg.height.baseVal.value]];
    }
  
    // Like d3.local, but with the name “__brush” rather than auto-generated.
    function local$1(node) {
      while (!node.__brush) if (!(node = node.parentNode)) return;
      return node.__brush;
    }
  
    function empty$1(extent) {
      return extent[0][0] === extent[1][0]
          || extent[0][1] === extent[1][1];
    }
  
    function brushSelection(node) {
      var state = node.__brush;
      return state ? state.dim.output(state.selection) : null;
    }
  
    function brushX() {
      return brush$1(X);
    }
  
    function brushY() {
      return brush$1(Y);
    }
  
    function brush() {
      return brush$1(XY);
    }
  
    function brush$1(dim) {
      var extent = defaultExtent$1,
          filter = defaultFilter$2,
          listeners = dispatch(brush, "start", "brush", "end"),
          handleSize = 6,
          touchending;
  
      function brush(group) {
        var overlay = group
            .property("__brush", initialize)
          .selectAll(".overlay")
          .data([type$1("overlay")]);
  
        overlay.enter().append("rect")
            .attr("class", "overlay")
            .attr("pointer-events", "all")
            .attr("cursor", cursors.overlay)
          .merge(overlay)
            .each(function() {
              var extent = local$1(this).extent;
              select(this)
                  .attr("x", extent[0][0])
                  .attr("y", extent[0][1])
                  .attr("width", extent[1][0] - extent[0][0])
                  .attr("height", extent[1][1] - extent[0][1]);
            });
  
        group.selectAll(".selection")
          .data([type$1("selection")])
          .enter().append("rect")
            .attr("class", "selection")
            .attr("cursor", cursors.selection)
            .attr("fill", "#777")
            .attr("fill-opacity", 0.3)
            .attr("stroke", "#fff")
            .attr("shape-rendering", "crispEdges");
  
        var handle = group.selectAll(".handle")
          .data(dim.handles, function(d) { return d.type; });
  
        handle.exit().remove();
  
        handle.enter().append("rect")
            .attr("class", function(d) { return "handle handle--" + d.type; })
            .attr("cursor", function(d) { return cursors[d.type]; });
  
        group
            .each(redraw)
            .attr("fill", "none")
            .attr("pointer-events", "all")
            .style("-webkit-tap-highlight-color", "rgba(0,0,0,0)")
            .on("mousedown.brush touchstart.brush", started);
      }
  
      brush.move = function(group, selection) {
        if (group.selection) {
          group
              .on("start.brush", function() { emitter(this, arguments).beforestart().start(); })
              .on("interrupt.brush end.brush", function() { emitter(this, arguments).end(); })
              .tween("brush", function() {
                var that = this,
                    state = that.__brush,
                    emit = emitter(that, arguments),
                    selection0 = state.selection,
                    selection1 = dim.input(typeof selection === "function" ? selection.apply(this, arguments) : selection, state.extent),
                    i = interpolate(selection0, selection1);
  
                function tween(t) {
                  state.selection = t === 1 && empty$1(selection1) ? null : i(t);
                  redraw.call(that);
                  emit.brush();
                }
  
                return selection0 && selection1 ? tween : tween(1);
              });
        } else {
          group
              .each(function() {
                var that = this,
                    args = arguments,
                    state = that.__brush,
                    selection1 = dim.input(typeof selection === "function" ? selection.apply(that, args) : selection, state.extent),
                    emit = emitter(that, args).beforestart();
  
                interrupt(that);
                state.selection = selection1 == null || empty$1(selection1) ? null : selection1;
                redraw.call(that);
                emit.start().brush().end();
              });
        }
      };
  
      function redraw() {
        var group = select(this),
            selection = local$1(this).selection;
  
        if (selection) {
          group.selectAll(".selection")
              .style("display", null)
              .attr("x", selection[0][0])
              .attr("y", selection[0][1])
              .attr("width", selection[1][0] - selection[0][0])
              .attr("height", selection[1][1] - selection[0][1]);
  
          group.selectAll(".handle")
              .style("display", null)
              .attr("x", function(d) { return d.type[d.type.length - 1] === "e" ? selection[1][0] - handleSize / 2 : selection[0][0] - handleSize / 2; })
              .attr("y", function(d) { return d.type[0] === "s" ? selection[1][1] - handleSize / 2 : selection[0][1] - handleSize / 2; })
              .attr("width", function(d) { return d.type === "n" || d.type === "s" ? selection[1][0] - selection[0][0] + handleSize : handleSize; })
              .attr("height", function(d) { return d.type === "e" || d.type === "w" ? selection[1][1] - selection[0][1] + handleSize : handleSize; });
        }
  
        else {
          group.selectAll(".selection,.handle")
              .style("display", "none")
              .attr("x", null)
              .attr("y", null)
              .attr("width", null)
              .attr("height", null);
        }
      }
  
      function emitter(that, args) {
        return that.__brush.emitter || new Emitter(that, args);
      }
  
      function Emitter(that, args) {
        this.that = that;
        this.args = args;
        this.state = that.__brush;
        this.active = 0;
      }
  
      Emitter.prototype = {
        beforestart: function() {
          if (++this.active === 1) this.state.emitter = this, this.starting = true;
          return this;
        },
        start: function() {
          if (this.starting) this.starting = false, this.emit("start");
          return this;
        },
        brush: function() {
          this.emit("brush");
          return this;
        },
        end: function() {
          if (--this.active === 0) delete this.state.emitter, this.emit("end");
          return this;
        },
        emit: function(type) {
          customEvent(new BrushEvent(brush, type, dim.output(this.state.selection)), listeners.apply, listeners, [type, this.that, this.args]);
        }
      };
  
      function started() {
        if (exports.event.touches) { if (exports.event.changedTouches.length < exports.event.touches.length) return noevent$2(); }
        else if (touchending) return;
        if (!filter.apply(this, arguments)) return;
  
        var that = this,
            type = exports.event.target.__data__.type,
            mode = (exports.event.metaKey ? type = "overlay" : type) === "selection" ? MODE_DRAG : (exports.event.altKey ? MODE_CENTER : MODE_HANDLE),
            signX = dim === Y ? null : signsX[type],
            signY = dim === X ? null : signsY[type],
            state = local$1(that),
            extent = state.extent,
            selection = state.selection,
            W = extent[0][0], w0, w1,
            N = extent[0][1], n0, n1,
            E = extent[1][0], e0, e1,
            S = extent[1][1], s0, s1,
            dx,
            dy,
            moving,
            shifting = signX && signY && exports.event.shiftKey,
            lockX,
            lockY,
            point0 = mouse(that),
            point = point0,
            emit = emitter(that, arguments).beforestart();
  
        if (type === "overlay") {
          state.selection = selection = [
            [w0 = dim === Y ? W : point0[0], n0 = dim === X ? N : point0[1]],
            [e0 = dim === Y ? E : w0, s0 = dim === X ? S : n0]
          ];
        } else {
          w0 = selection[0][0];
          n0 = selection[0][1];
          e0 = selection[1][0];
          s0 = selection[1][1];
        }
  
        w1 = w0;
        n1 = n0;
        e1 = e0;
        s1 = s0;
  
        var group = select(that)
            .attr("pointer-events", "none");
  
        var overlay = group.selectAll(".overlay")
            .attr("cursor", cursors[type]);
  
        if (exports.event.touches) {
          group
              .on("touchmove.brush", moved, true)
              .on("touchend.brush touchcancel.brush", ended, true);
        } else {
          var view = select(exports.event.view)
              .on("keydown.brush", keydowned, true)
              .on("keyup.brush", keyupped, true)
              .on("mousemove.brush", moved, true)
              .on("mouseup.brush", ended, true);
  
          dragDisable(exports.event.view);
        }
  
        nopropagation$2();
        interrupt(that);
        redraw.call(that);
        emit.start();
  
        function moved() {
          var point1 = mouse(that);
          if (shifting && !lockX && !lockY) {
            if (Math.abs(point1[0] - point[0]) > Math.abs(point1[1] - point[1])) lockY = true;
            else lockX = true;
          }
          point = point1;
          moving = true;
          noevent$2();
          move();
        }
  
        function move() {
          var t;
  
          dx = point[0] - point0[0];
          dy = point[1] - point0[1];
  
          switch (mode) {
            case MODE_SPACE:
            case MODE_DRAG: {
              if (signX) dx = Math.max(W - w0, Math.min(E - e0, dx)), w1 = w0 + dx, e1 = e0 + dx;
              if (signY) dy = Math.max(N - n0, Math.min(S - s0, dy)), n1 = n0 + dy, s1 = s0 + dy;
              break;
            }
            case MODE_HANDLE: {
              if (signX < 0) dx = Math.max(W - w0, Math.min(E - w0, dx)), w1 = w0 + dx, e1 = e0;
              else if (signX > 0) dx = Math.max(W - e0, Math.min(E - e0, dx)), w1 = w0, e1 = e0 + dx;
              if (signY < 0) dy = Math.max(N - n0, Math.min(S - n0, dy)), n1 = n0 + dy, s1 = s0;
              else if (signY > 0) dy = Math.max(N - s0, Math.min(S - s0, dy)), n1 = n0, s1 = s0 + dy;
              break;
            }
            case MODE_CENTER: {
              if (signX) w1 = Math.max(W, Math.min(E, w0 - dx * signX)), e1 = Math.max(W, Math.min(E, e0 + dx * signX));
              if (signY) n1 = Math.max(N, Math.min(S, n0 - dy * signY)), s1 = Math.max(N, Math.min(S, s0 + dy * signY));
              break;
            }
          }
  
          if (e1 < w1) {
            signX *= -1;
            t = w0, w0 = e0, e0 = t;
            t = w1, w1 = e1, e1 = t;
            if (type in flipX) overlay.attr("cursor", cursors[type = flipX[type]]);
          }
  
          if (s1 < n1) {
            signY *= -1;
            t = n0, n0 = s0, s0 = t;
            t = n1, n1 = s1, s1 = t;
            if (type in flipY) overlay.attr("cursor", cursors[type = flipY[type]]);
          }
  
          selection = state.selection; // May be set by brush.move!
  
          if (lockX) w1 = selection[0][0], e1 = selection[1][0];
          if (lockY) n1 = selection[0][1], s1 = selection[1][1];
  
          if (selection[0][0] !== w1
              || selection[0][1] !== n1
              || selection[1][0] !== e1
              || selection[1][1] !== s1) {
            state.selection = [[w1, n1], [e1, s1]];
            redraw.call(that);
            emit.brush();
          }
        }
  
        function ended() {
          nopropagation$2();
          if (exports.event.touches) {
            if (exports.event.touches.length) return;
            if (touchending) clearTimeout(touchending);
            touchending = setTimeout(function() { touchending = null; }, 500); // Ghost clicks are delayed!
            group.on("touchmove.brush touchend.brush touchcancel.brush", null);
          } else {
            dragEnable(exports.event.view, moving);
            view.on("keydown.brush keyup.brush mousemove.brush mouseup.brush", null);
          }
          group.attr("pointer-events", "all");
          overlay.attr("cursor", cursors.overlay);
          if (empty$1(selection)) state.selection = null, redraw.call(that);
          emit.end();
        }
  
        function keydowned() {
          switch (exports.event.keyCode) {
            case 16: { // SHIFT
              shifting = signX && signY;
              break;
            }
            case 18: { // ALT
              if (mode === MODE_HANDLE) {
                if (signX) e0 = e1 - dx * signX, w0 = w1 + dx * signX;
                if (signY) s0 = s1 - dy * signY, n0 = n1 + dy * signY;
                mode = MODE_CENTER;
                move();
              }
              break;
            }
            case 32: { // SPACE; takes priority over ALT
              if (mode === MODE_HANDLE || mode === MODE_CENTER) {
                if (signX < 0) e0 = e1 - dx; else if (signX > 0) w0 = w1 - dx;
                if (signY < 0) s0 = s1 - dy; else if (signY > 0) n0 = n1 - dy;
                mode = MODE_SPACE;
                overlay.attr("cursor", cursors.selection);
                move();
              }
              break;
            }
            default: return;
          }
          noevent$2();
        }
  
        function keyupped() {
          switch (exports.event.keyCode) {
            case 16: { // SHIFT
              if (shifting) {
                lockX = lockY = shifting = false;
                move();
              }
              break;
            }
            case 18: { // ALT
              if (mode === MODE_CENTER) {
                if (signX < 0) e0 = e1; else if (signX > 0) w0 = w1;
                if (signY < 0) s0 = s1; else if (signY > 0) n0 = n1;
                mode = MODE_HANDLE;
                move();
              }
              break;
            }
            case 32: { // SPACE
              if (mode === MODE_SPACE) {
                if (exports.event.altKey) {
                  if (signX) e0 = e1 - dx * signX, w0 = w1 + dx * signX;
                  if (signY) s0 = s1 - dy * signY, n0 = n1 + dy * signY;
                  mode = MODE_CENTER;
                } else {
                  if (signX < 0) e0 = e1; else if (signX > 0) w0 = w1;
                  if (signY < 0) s0 = s1; else if (signY > 0) n0 = n1;
                  mode = MODE_HANDLE;
                }
                overlay.attr("cursor", cursors[type]);
                move();
              }
              break;
            }
            default: return;
          }
          noevent$2();
        }
      }
  
      function initialize() {
        var state = this.__brush || {selection: null};
        state.extent = extent.apply(this, arguments);
        state.dim = dim;
        return state;
      }
  
      brush.extent = function(_) {
        return arguments.length ? (extent = typeof _ === "function" ? _ : constant$10([[+_[0][0], +_[0][1]], [+_[1][0], +_[1][1]]]), brush) : extent;
      };
  
      brush.filter = function(_) {
        return arguments.length ? (filter = typeof _ === "function" ? _ : constant$10(!!_), brush) : filter;
      };
  
      brush.handleSize = function(_) {
        return arguments.length ? (handleSize = +_, brush) : handleSize;
      };
  
      brush.on = function() {
        var value = listeners.on.apply(listeners, arguments);
        return value === listeners ? brush : value;
      };
  
      return brush;
    }
  
    // Adds floating point numbers with twice the normal precision.
    // Reference: J. R. Shewchuk, Adaptive Precision Floating-Point Arithmetic and
    // Fast Robust Geometric Predicates, Discrete & Computational Geometry 18(3)
    // 305–363 (1997).
    // Code adapted from GeographicLib by Charles F. F. Karney,
    // http://geographiclib.sourceforge.net/
  
    function adder() {
      return new Adder;
    }
  
    function Adder() {
      this.reset();
    }
  
    Adder.prototype = {
      constructor: Adder,
      reset: function() {
        this.s = // rounded value
        this.t = 0; // exact error
      },
      add: function(y) {
        add$1(temp, y, this.t);
        add$1(this, temp.s, this.s);
        if (this.s) this.t += temp.t;
        else this.s = temp.t;
      },
      valueOf: function() {
        return this.s;
      }
    };
  
    var temp = new Adder;
  
    function add$1(adder, a, b) {
      var x = adder.s = a + b,
          bv = x - a,
          av = x - bv;
      adder.t = (a - av) + (b - bv);
    }
  
    var epsilon$4 = 1e-6;
    var epsilon2$2 = 1e-12;
    var pi$3 = Math.PI;
    var halfPi$2 = pi$3 / 2;
    var quarterPi = pi$3 / 4;
    var tau$3 = pi$3 * 2;
  
    var degrees$1 = 180 / pi$3;
    var radians = pi$3 / 180;
  
    var abs = Math.abs;
    var atan = Math.atan;
    var atan2 = Math.atan2;
    var cos = Math.cos;
    var ceil = Math.ceil;
    var exp = Math.exp;
    var log$1 = Math.log;
    var pow$1 = Math.pow;
    var sin = Math.sin;
    var sign$1 = Math.sign || function(x) { return x > 0 ? 1 : x < 0 ? -1 : 0; };
    var sqrt$1 = Math.sqrt;
    var tan = Math.tan;
  
    function acos(x) {
      return x > 1 ? 0 : x < -1 ? pi$3 : Math.acos(x);
    }
  
    function asin$1(x) {
      return x > 1 ? halfPi$2 : x < -1 ? -halfPi$2 : Math.asin(x);
    }
  
    function haversin(x) {
      return (x = sin(x / 2)) * x;
    }
  
    function noop$2() {}
  
    function streamGeometry(geometry, stream) {
      if (geometry && streamGeometryType.hasOwnProperty(geometry.type)) {
        streamGeometryType[geometry.type](geometry, stream);
      }
    }
  
    var streamObjectType = {
      Feature: function(feature, stream) {
        streamGeometry(feature.geometry, stream);
      },
      FeatureCollection: function(object, stream) {
        var features = object.features, i = -1, n = features.length;
        while (++i < n) streamGeometry(features[i].geometry, stream);
      }
    };
  
    var streamGeometryType = {
      Sphere: function(object, stream) {
        stream.sphere();
      },
      Point: function(object, stream) {
        object = object.coordinates;
        stream.point(object[0], object[1], object[2]);
      },
      MultiPoint: function(object, stream) {
        var coordinates = object.coordinates, i = -1, n = coordinates.length;
        while (++i < n) object = coordinates[i], stream.point(object[0], object[1], object[2]);
      },
      LineString: function(object, stream) {
        streamLine(object.coordinates, stream, 0);
      },
      MultiLineString: function(object, stream) {
        var coordinates = object.coordinates, i = -1, n = coordinates.length;
        while (++i < n) streamLine(coordinates[i], stream, 0);
      },
      Polygon: function(object, stream) {
        streamPolygon(object.coordinates, stream);
      },
      MultiPolygon: function(object, stream) {
        var coordinates = object.coordinates, i = -1, n = coordinates.length;
        while (++i < n) streamPolygon(coordinates[i], stream);
      },
      GeometryCollection: function(object, stream) {
        var geometries = object.geometries, i = -1, n = geometries.length;
        while (++i < n) streamGeometry(geometries[i], stream);
      }
    };
  
    function streamLine(coordinates, stream, closed) {
      var i = -1, n = coordinates.length - closed, coordinate;
      stream.lineStart();
      while (++i < n) coordinate = coordinates[i], stream.point(coordinate[0], coordinate[1], coordinate[2]);
      stream.lineEnd();
    }
  
    function streamPolygon(coordinates, stream) {
      var i = -1, n = coordinates.length;
      stream.polygonStart();
      while (++i < n) streamLine(coordinates[i], stream, 1);
      stream.polygonEnd();
    }
  
    function geoStream(object, stream) {
      if (object && streamObjectType.hasOwnProperty(object.type)) {
        streamObjectType[object.type](object, stream);
      } else {
        streamGeometry(object, stream);
      }
    }
  
    var areaRingSum = adder();
  
    var areaSum = adder();
    var lambda00;
    var phi00;
    var lambda0;
    var cosPhi0;
    var sinPhi0;
    var areaStream = {
      point: noop$2,
      lineStart: noop$2,
      lineEnd: noop$2,
      polygonStart: function() {
        areaRingSum.reset();
        areaStream.lineStart = areaRingStart;
        areaStream.lineEnd = areaRingEnd;
      },
      polygonEnd: function() {
        var areaRing = +areaRingSum;
        areaSum.add(areaRing < 0 ? tau$3 + areaRing : areaRing);
        this.lineStart = this.lineEnd = this.point = noop$2;
      },
      sphere: function() {
        areaSum.add(tau$3);
      }
    };
  
    function areaRingStart() {
      areaStream.point = areaPointFirst;
    }
  
    function areaRingEnd() {
      areaPoint(lambda00, phi00);
    }
  
    function areaPointFirst(lambda, phi) {
      areaStream.point = areaPoint;
      lambda00 = lambda, phi00 = phi;
      lambda *= radians, phi *= radians;
      lambda0 = lambda, cosPhi0 = cos(phi = phi / 2 + quarterPi), sinPhi0 = sin(phi);
    }
  
    function areaPoint(lambda, phi) {
      lambda *= radians, phi *= radians;
      phi = phi / 2 + quarterPi; // half the angular distance from south pole
  
      // Spherical excess E for a spherical triangle with vertices: south pole,
      // previous point, current point.  Uses a formula derived from Cagnoli’s
      // theorem.  See Todhunter, Spherical Trig. (1871), Sec. 103, Eq. (2).
      var dLambda = lambda - lambda0,
          sdLambda = dLambda >= 0 ? 1 : -1,
          adLambda = sdLambda * dLambda,
          cosPhi = cos(phi),
          sinPhi = sin(phi),
          k = sinPhi0 * sinPhi,
          u = cosPhi0 * cosPhi + k * cos(adLambda),
          v = k * sdLambda * sin(adLambda);
      areaRingSum.add(atan2(v, u));
  
      // Advance the previous points.
      lambda0 = lambda, cosPhi0 = cosPhi, sinPhi0 = sinPhi;
    }
  
    function area$2(object) {
      areaSum.reset();
      geoStream(object, areaStream);
      return areaSum * 2;
    }
  
    function spherical(cartesian) {
      return [atan2(cartesian[1], cartesian[0]), asin$1(cartesian[2])];
    }
  
    function cartesian(spherical) {
      var lambda = spherical[0], phi = spherical[1], cosPhi = cos(phi);
      return [cosPhi * cos(lambda), cosPhi * sin(lambda), sin(phi)];
    }
  
    function cartesianDot(a, b) {
      return a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
    }
  
    function cartesianCross(a, b) {
      return [a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0]];
    }
  
    // TODO return a
    function cartesianAddInPlace(a, b) {
      a[0] += b[0], a[1] += b[1], a[2] += b[2];
    }
  
    function cartesianScale(vector, k) {
      return [vector[0] * k, vector[1] * k, vector[2] * k];
    }
  
    // TODO return d
    function cartesianNormalizeInPlace(d) {
      var l = sqrt$1(d[0] * d[0] + d[1] * d[1] + d[2] * d[2]);
      d[0] /= l, d[1] /= l, d[2] /= l;
    }
  
  var   lambda0$1;
    var phi0;
    var lambda1;
    var phi1;
    var lambda2;
  var   lambda00$1;
  var   phi00$1;
    var p0;
    var deltaSum = adder();
    var ranges;
  var   range$1;
    var boundsStream = {
      point: boundsPoint,
      lineStart: boundsLineStart,
      lineEnd: boundsLineEnd,
      polygonStart: function() {
        boundsStream.point = boundsRingPoint;
        boundsStream.lineStart = boundsRingStart;
        boundsStream.lineEnd = boundsRingEnd;
        deltaSum.reset();
        areaStream.polygonStart();
      },
      polygonEnd: function() {
        areaStream.polygonEnd();
        boundsStream.point = boundsPoint;
        boundsStream.lineStart = boundsLineStart;
        boundsStream.lineEnd = boundsLineEnd;
        if (areaRingSum < 0) lambda0$1 = -(lambda1 = 180), phi0 = -(phi1 = 90);
        else if (deltaSum > epsilon$4) phi1 = 90;
        else if (deltaSum < -epsilon$4) phi0 = -90;
        range$1[0] = lambda0$1, range$1[1] = lambda1;
      }
    };
  
    function boundsPoint(lambda, phi) {
      ranges.push(range$1 = [lambda0$1 = lambda, lambda1 = lambda]);
      if (phi < phi0) phi0 = phi;
      if (phi > phi1) phi1 = phi;
    }
  
    function linePoint(lambda, phi) {
      var p = cartesian([lambda * radians, phi * radians]);
      if (p0) {
        var normal = cartesianCross(p0, p),
            equatorial = [normal[1], -normal[0], 0],
            inflection = cartesianCross(equatorial, normal);
        cartesianNormalizeInPlace(inflection);
        inflection = spherical(inflection);
        var delta = lambda - lambda2,
            sign = delta > 0 ? 1 : -1,
            lambdai = inflection[0] * degrees$1 * sign,
            phii,
            antimeridian = abs(delta) > 180;
        if (antimeridian ^ (sign * lambda2 < lambdai && lambdai < sign * lambda)) {
          phii = inflection[1] * degrees$1;
          if (phii > phi1) phi1 = phii;
        } else if (lambdai = (lambdai + 360) % 360 - 180, antimeridian ^ (sign * lambda2 < lambdai && lambdai < sign * lambda)) {
          phii = -inflection[1] * degrees$1;
          if (phii < phi0) phi0 = phii;
        } else {
          if (phi < phi0) phi0 = phi;
          if (phi > phi1) phi1 = phi;
        }
        if (antimeridian) {
          if (lambda < lambda2) {
            if (angle(lambda0$1, lambda) > angle(lambda0$1, lambda1)) lambda1 = lambda;
          } else {
            if (angle(lambda, lambda1) > angle(lambda0$1, lambda1)) lambda0$1 = lambda;
          }
        } else {
          if (lambda1 >= lambda0$1) {
            if (lambda < lambda0$1) lambda0$1 = lambda;
            if (lambda > lambda1) lambda1 = lambda;
          } else {
            if (lambda > lambda2) {
              if (angle(lambda0$1, lambda) > angle(lambda0$1, lambda1)) lambda1 = lambda;
            } else {
              if (angle(lambda, lambda1) > angle(lambda0$1, lambda1)) lambda0$1 = lambda;
            }
          }
        }
      } else {
        boundsPoint(lambda, phi);
      }
      p0 = p, lambda2 = lambda;
    }
  
    function boundsLineStart() {
      boundsStream.point = linePoint;
    }
  
    function boundsLineEnd() {
      range$1[0] = lambda0$1, range$1[1] = lambda1;
      boundsStream.point = boundsPoint;
      p0 = null;
    }
  
    function boundsRingPoint(lambda, phi) {
      if (p0) {
        var delta = lambda - lambda2;
        deltaSum.add(abs(delta) > 180 ? delta + (delta > 0 ? 360 : -360) : delta);
      } else {
        lambda00$1 = lambda, phi00$1 = phi;
      }
      areaStream.point(lambda, phi);
      linePoint(lambda, phi);
    }
  
    function boundsRingStart() {
      areaStream.lineStart();
    }
  
    function boundsRingEnd() {
      boundsRingPoint(lambda00$1, phi00$1);
      areaStream.lineEnd();
      if (abs(deltaSum) > epsilon$4) lambda0$1 = -(lambda1 = 180);
      range$1[0] = lambda0$1, range$1[1] = lambda1;
      p0 = null;
    }
  
    // Finds the left-right distance between two longitudes.
    // This is almost the same as (lambda1 - lambda0 + 360°) % 360°, except that we want
    // the distance between ±180° to be 360°.
    function angle(lambda0, lambda1) {
      return (lambda1 -= lambda0) < 0 ? lambda1 + 360 : lambda1;
    }
  
    function rangeCompare(a, b) {
      return a[0] - b[0];
    }
  
    function rangeContains(range, x) {
      return range[0] <= range[1] ? range[0] <= x && x <= range[1] : x < range[0] || range[1] < x;
    }
  
    function bounds(feature) {
      var i, n, a, b, merged, deltaMax, delta;
  
      phi1 = lambda1 = -(lambda0$1 = phi0 = Infinity);
      ranges = [];
      geoStream(feature, boundsStream);
  
      // First, sort ranges by their minimum longitudes.
      if (n = ranges.length) {
        ranges.sort(rangeCompare);
  
        // Then, merge any ranges that overlap.
        for (i = 1, a = ranges[0], merged = [a]; i < n; ++i) {
          b = ranges[i];
          if (rangeContains(a, b[0]) || rangeContains(a, b[1])) {
            if (angle(a[0], b[1]) > angle(a[0], a[1])) a[1] = b[1];
            if (angle(b[0], a[1]) > angle(a[0], a[1])) a[0] = b[0];
          } else {
            merged.push(a = b);
          }
        }
  
        // Finally, find the largest gap between the merged ranges.
        // The final bounding box will be the inverse of this gap.
        for (deltaMax = -Infinity, n = merged.length - 1, i = 0, a = merged[n]; i <= n; a = b, ++i) {
          b = merged[i];
          if ((delta = angle(a[1], b[0])) > deltaMax) deltaMax = delta, lambda0$1 = b[0], lambda1 = a[1];
        }
      }
  
      ranges = range$1 = null;
  
      return lambda0$1 === Infinity || phi0 === Infinity
          ? [[NaN, NaN], [NaN, NaN]]
          : [[lambda0$1, phi0], [lambda1, phi1]];
    }
  
    var W0;
    var W1;
    var X0;
    var Y0;
    var Z0;
    var X1;
    var Y1;
    var Z1;
    var X2;
    var Y2;
    var Z2;
  var   lambda00$2;
  var   phi00$2;
    var x0;
    var y0;
    var z0;
    // previous point
  
    var centroidStream = {
      sphere: noop$2,
      point: centroidPoint,
      lineStart: centroidLineStart,
      lineEnd: centroidLineEnd,
      polygonStart: function() {
        centroidStream.lineStart = centroidRingStart;
        centroidStream.lineEnd = centroidRingEnd;
      },
      polygonEnd: function() {
        centroidStream.lineStart = centroidLineStart;
        centroidStream.lineEnd = centroidLineEnd;
      }
    };
  
    // Arithmetic mean of Cartesian vectors.
    function centroidPoint(lambda, phi) {
      lambda *= radians, phi *= radians;
      var cosPhi = cos(phi);
      centroidPointCartesian(cosPhi * cos(lambda), cosPhi * sin(lambda), sin(phi));
    }
  
    function centroidPointCartesian(x, y, z) {
      ++W0;
      X0 += (x - X0) / W0;
      Y0 += (y - Y0) / W0;
      Z0 += (z - Z0) / W0;
    }
  
    function centroidLineStart() {
      centroidStream.point = centroidLinePointFirst;
    }
  
    function centroidLinePointFirst(lambda, phi) {
      lambda *= radians, phi *= radians;
      var cosPhi = cos(phi);
      x0 = cosPhi * cos(lambda);
      y0 = cosPhi * sin(lambda);
      z0 = sin(phi);
      centroidStream.point = centroidLinePoint;
      centroidPointCartesian(x0, y0, z0);
    }
  
    function centroidLinePoint(lambda, phi) {
      lambda *= radians, phi *= radians;
      var cosPhi = cos(phi),
          x = cosPhi * cos(lambda),
          y = cosPhi * sin(lambda),
          z = sin(phi),
          w = atan2(sqrt$1((w = y0 * z - z0 * y) * w + (w = z0 * x - x0 * z) * w + (w = x0 * y - y0 * x) * w), x0 * x + y0 * y + z0 * z);
      W1 += w;
      X1 += w * (x0 + (x0 = x));
      Y1 += w * (y0 + (y0 = y));
      Z1 += w * (z0 + (z0 = z));
      centroidPointCartesian(x0, y0, z0);
    }
  
    function centroidLineEnd() {
      centroidStream.point = centroidPoint;
    }
  
    // See J. E. Brock, The Inertia Tensor for a Spherical Triangle,
    // J. Applied Mechanics 42, 239 (1975).
    function centroidRingStart() {
      centroidStream.point = centroidRingPointFirst;
    }
  
    function centroidRingEnd() {
      centroidRingPoint(lambda00$2, phi00$2);
      centroidStream.point = centroidPoint;
    }
  
    function centroidRingPointFirst(lambda, phi) {
      lambda00$2 = lambda, phi00$2 = phi;
      lambda *= radians, phi *= radians;
      centroidStream.point = centroidRingPoint;
      var cosPhi = cos(phi);
      x0 = cosPhi * cos(lambda);
      y0 = cosPhi * sin(lambda);
      z0 = sin(phi);
      centroidPointCartesian(x0, y0, z0);
    }
  
    function centroidRingPoint(lambda, phi) {
      lambda *= radians, phi *= radians;
      var cosPhi = cos(phi),
          x = cosPhi * cos(lambda),
          y = cosPhi * sin(lambda),
          z = sin(phi),
          cx = y0 * z - z0 * y,
          cy = z0 * x - x0 * z,
          cz = x0 * y - y0 * x,
          m = sqrt$1(cx * cx + cy * cy + cz * cz),
          u = x0 * x + y0 * y + z0 * z,
          v = m && -acos(u) / m, // area weight
          w = atan2(m, u); // line weight
      X2 += v * cx;
      Y2 += v * cy;
      Z2 += v * cz;
      W1 += w;
      X1 += w * (x0 + (x0 = x));
      Y1 += w * (y0 + (y0 = y));
      Z1 += w * (z0 + (z0 = z));
      centroidPointCartesian(x0, y0, z0);
    }
  
    function centroid$1(object) {
      W0 = W1 =
      X0 = Y0 = Z0 =
      X1 = Y1 = Z1 =
      X2 = Y2 = Z2 = 0;
      geoStream(object, centroidStream);
  
      var x = X2,
          y = Y2,
          z = Z2,
          m = x * x + y * y + z * z;
  
      // If the area-weighted ccentroid is undefined, fall back to length-weighted ccentroid.
      if (m < epsilon2$2) {
        x = X1, y = Y1, z = Z1;
        // If the feature has zero length, fall back to arithmetic mean of point vectors.
        if (W1 < epsilon$4) x = X0, y = Y0, z = Z0;
        m = x * x + y * y + z * z;
        // If the feature still has an undefined ccentroid, then return.
        if (m < epsilon2$2) return [NaN, NaN];
      }
  
      return [atan2(y, x) * degrees$1, asin$1(z / sqrt$1(m)) * degrees$1];
    }
  
    function constant$11(x) {
      return function() {
        return x;
      };
    }
  
    function compose(a, b) {
  
      function compose(x, y) {
        return x = a(x, y), b(x[0], x[1]);
      }
  
      if (a.invert && b.invert) compose.invert = function(x, y) {
        return x = b.invert(x, y), x && a.invert(x[0], x[1]);
      };
  
      return compose;
    }
  
    function rotationIdentity(lambda, phi) {
      return [lambda > pi$3 ? lambda - tau$3 : lambda < -pi$3 ? lambda + tau$3 : lambda, phi];
    }
  
    rotationIdentity.invert = rotationIdentity;
  
    function rotateRadians(deltaLambda, deltaPhi, deltaGamma) {
      return (deltaLambda %= tau$3) ? (deltaPhi || deltaGamma ? compose(rotationLambda(deltaLambda), rotationPhiGamma(deltaPhi, deltaGamma))
        : rotationLambda(deltaLambda))
        : (deltaPhi || deltaGamma ? rotationPhiGamma(deltaPhi, deltaGamma)
        : rotationIdentity);
    }
  
    function forwardRotationLambda(deltaLambda) {
      return function(lambda, phi) {
        return lambda += deltaLambda, [lambda > pi$3 ? lambda - tau$3 : lambda < -pi$3 ? lambda + tau$3 : lambda, phi];
      };
    }
  
    function rotationLambda(deltaLambda) {
      var rotation = forwardRotationLambda(deltaLambda);
      rotation.invert = forwardRotationLambda(-deltaLambda);
      return rotation;
    }
  
    function rotationPhiGamma(deltaPhi, deltaGamma) {
      var cosDeltaPhi = cos(deltaPhi),
          sinDeltaPhi = sin(deltaPhi),
          cosDeltaGamma = cos(deltaGamma),
          sinDeltaGamma = sin(deltaGamma);
  
      function rotation(lambda, phi) {
        var cosPhi = cos(phi),
            x = cos(lambda) * cosPhi,
            y = sin(lambda) * cosPhi,
            z = sin(phi),
            k = z * cosDeltaPhi + x * sinDeltaPhi;
        return [
          atan2(y * cosDeltaGamma - k * sinDeltaGamma, x * cosDeltaPhi - z * sinDeltaPhi),
          asin$1(k * cosDeltaGamma + y * sinDeltaGamma)
        ];
      }
  
      rotation.invert = function(lambda, phi) {
        var cosPhi = cos(phi),
            x = cos(lambda) * cosPhi,
            y = sin(lambda) * cosPhi,
            z = sin(phi),
            k = z * cosDeltaGamma - y * sinDeltaGamma;
        return [
          atan2(y * cosDeltaGamma + z * sinDeltaGamma, x * cosDeltaPhi + k * sinDeltaPhi),
          asin$1(k * cosDeltaPhi - x * sinDeltaPhi)
        ];
      };
  
      return rotation;
    }
  
    function rotation(rotate) {
      rotate = rotateRadians(rotate[0] * radians, rotate[1] * radians, rotate.length > 2 ? rotate[2] * radians : 0);
  
      function forward(coordinates) {
        coordinates = rotate(coordinates[0] * radians, coordinates[1] * radians);
        return coordinates[0] *= degrees$1, coordinates[1] *= degrees$1, coordinates;
      }
  
      forward.invert = function(coordinates) {
        coordinates = rotate.invert(coordinates[0] * radians, coordinates[1] * radians);
        return coordinates[0] *= degrees$1, coordinates[1] *= degrees$1, coordinates;
      };
  
      return forward;
    }
  
    // Generates a circle centered at [0°, 0°], with a given radius and precision.
    function circleStream(stream, radius, delta, direction, t0, t1) {
      if (!delta) return;
      var cosRadius = cos(radius),
          sinRadius = sin(radius),
          step = direction * delta;
      if (t0 == null) {
        t0 = radius + direction * tau$3;
        t1 = radius - step / 2;
      } else {
        t0 = circleRadius(cosRadius, t0);
        t1 = circleRadius(cosRadius, t1);
        if (direction > 0 ? t0 < t1 : t0 > t1) t0 += direction * tau$3;
      }
      for (var point, t = t0; direction > 0 ? t > t1 : t < t1; t -= step) {
        point = spherical([cosRadius, -sinRadius * cos(t), -sinRadius * sin(t)]);
        stream.point(point[0], point[1]);
      }
    }
  
    // Returns the signed angle of a cartesian point relative to [cosRadius, 0, 0].
    function circleRadius(cosRadius, point) {
      point = cartesian(point), point[0] -= cosRadius;
      cartesianNormalizeInPlace(point);
      var radius = acos(-point[1]);
      return ((-point[2] < 0 ? -radius : radius) + tau$3 - epsilon$4) % tau$3;
    }
  
    function circle$1() {
      var center = constant$11([0, 0]),
          radius = constant$11(90),
          precision = constant$11(6),
          ring,
          rotate,
          stream = {point: point};
  
      function point(x, y) {
        ring.push(x = rotate(x, y));
        x[0] *= degrees$1, x[1] *= degrees$1;
      }
  
      function circle() {
        var c = center.apply(this, arguments),
            r = radius.apply(this, arguments) * radians,
            p = precision.apply(this, arguments) * radians;
        ring = [];
        rotate = rotateRadians(-c[0] * radians, -c[1] * radians, 0).invert;
        circleStream(stream, r, p, 1);
        c = {type: "Polygon", coordinates: [ring]};
        ring = rotate = null;
        return c;
      }
  
      circle.center = function(_) {
        return arguments.length ? (center = typeof _ === "function" ? _ : constant$11([+_[0], +_[1]]), circle) : center;
      };
  
      circle.radius = function(_) {
        return arguments.length ? (radius = typeof _ === "function" ? _ : constant$11(+_), circle) : radius;
      };
  
      circle.precision = function(_) {
        return arguments.length ? (precision = typeof _ === "function" ? _ : constant$11(+_), circle) : precision;
      };
  
      return circle;
    }
  
    function clipBuffer() {
      var lines = [],
          line;
      return {
        point: function(x, y) {
          line.push([x, y]);
        },
        lineStart: function() {
          lines.push(line = []);
        },
        lineEnd: noop$2,
        rejoin: function() {
          if (lines.length > 1) lines.push(lines.pop().concat(lines.shift()));
        },
        result: function() {
          var result = lines;
          lines = [];
          line = null;
          return result;
        }
      };
    }
  
    function clipLine(a, b, x0, y0, x1, y1) {
      var ax = a[0],
          ay = a[1],
          bx = b[0],
          by = b[1],
          t0 = 0,
          t1 = 1,
          dx = bx - ax,
          dy = by - ay,
          r;
  
      r = x0 - ax;
      if (!dx && r > 0) return;
      r /= dx;
      if (dx < 0) {
        if (r < t0) return;
        if (r < t1) t1 = r;
      } else if (dx > 0) {
        if (r > t1) return;
        if (r > t0) t0 = r;
      }
  
      r = x1 - ax;
      if (!dx && r < 0) return;
      r /= dx;
      if (dx < 0) {
        if (r > t1) return;
        if (r > t0) t0 = r;
      } else if (dx > 0) {
        if (r < t0) return;
        if (r < t1) t1 = r;
      }
  
      r = y0 - ay;
      if (!dy && r > 0) return;
      r /= dy;
      if (dy < 0) {
        if (r < t0) return;
        if (r < t1) t1 = r;
      } else if (dy > 0) {
        if (r > t1) return;
        if (r > t0) t0 = r;
      }
  
      r = y1 - ay;
      if (!dy && r < 0) return;
      r /= dy;
      if (dy < 0) {
        if (r > t1) return;
        if (r > t0) t0 = r;
      } else if (dy > 0) {
        if (r < t0) return;
        if (r < t1) t1 = r;
      }
  
      if (t0 > 0) a[0] = ax + t0 * dx, a[1] = ay + t0 * dy;
      if (t1 < 1) b[0] = ax + t1 * dx, b[1] = ay + t1 * dy;
      return true;
    }
  
    function pointEqual(a, b) {
      return abs(a[0] - b[0]) < epsilon$4 && abs(a[1] - b[1]) < epsilon$4;
    }
  
    function Intersection(point, points, other, entry) {
      this.x = point;
      this.z = points;
      this.o = other; // another intersection
      this.e = entry; // is an entry?
      this.v = false; // visited
      this.n = this.p = null; // next & previous
    }
  
    // A generalized polygon clipping algorithm: given a polygon that has been cut
    // into its visible line segments, and rejoins the segments by interpolating
    // along the clip edge.
    function clipPolygon(segments, compareIntersection, startInside, interpolate, stream) {
      var subject = [],
          clip = [],
          i,
          n;
  
      segments.forEach(function(segment) {
        if ((n = segment.length - 1) <= 0) return;
        var n, p0 = segment[0], p1 = segment[n], x;
  
        // If the first and last points of a segment are coincident, then treat as a
        // closed ring. TODO if all rings are closed, then the winding order of the
        // exterior ring should be checked.
        if (pointEqual(p0, p1)) {
          stream.lineStart();
          for (i = 0; i < n; ++i) stream.point((p0 = segment[i])[0], p0[1]);
          stream.lineEnd();
          return;
        }
  
        subject.push(x = new Intersection(p0, segment, null, true));
        clip.push(x.o = new Intersection(p0, null, x, false));
        subject.push(x = new Intersection(p1, segment, null, false));
        clip.push(x.o = new Intersection(p1, null, x, true));
      });
  
      if (!subject.length) return;
  
      clip.sort(compareIntersection);
      link$1(subject);
      link$1(clip);
  
      for (i = 0, n = clip.length; i < n; ++i) {
        clip[i].e = startInside = !startInside;
      }
  
      var start = subject[0],
          points,
          point;
  
      while (1) {
        // Find first unvisited intersection.
        var current = start,
            isSubject = true;
        while (current.v) if ((current = current.n) === start) return;
        points = current.z;
        stream.lineStart();
        do {
          current.v = current.o.v = true;
          if (current.e) {
            if (isSubject) {
              for (i = 0, n = points.length; i < n; ++i) stream.point((point = points[i])[0], point[1]);
            } else {
              interpolate(current.x, current.n.x, 1, stream);
            }
            current = current.n;
          } else {
            if (isSubject) {
              points = current.p.z;
              for (i = points.length - 1; i >= 0; --i) stream.point((point = points[i])[0], point[1]);
            } else {
              interpolate(current.x, current.p.x, -1, stream);
            }
            current = current.p;
          }
          current = current.o;
          points = current.z;
          isSubject = !isSubject;
        } while (!current.v);
        stream.lineEnd();
      }
    }
  
    function link$1(array) {
      if (!(n = array.length)) return;
      var n,
          i = 0,
          a = array[0],
          b;
      while (++i < n) {
        a.n = b = array[i];
        b.p = a;
        a = b;
      }
      a.n = b = array[0];
      b.p = a;
    }
  
    var clipMax = 1e9;
    var clipMin = -clipMax;
    // TODO Use d3-polygon’s polygonContains here for the ring check?
    // TODO Eliminate duplicate buffering in clipBuffer and polygon.push?
  
    function clipExtent(x0, y0, x1, y1) {
  
      function visible(x, y) {
        return x0 <= x && x <= x1 && y0 <= y && y <= y1;
      }
  
      function interpolate(from, to, direction, stream) {
        var a = 0, a1 = 0;
        if (from == null
            || (a = corner(from, direction)) !== (a1 = corner(to, direction))
            || comparePoint(from, to) < 0 ^ direction > 0) {
          do stream.point(a === 0 || a === 3 ? x0 : x1, a > 1 ? y1 : y0);
          while ((a = (a + direction + 4) % 4) !== a1);
        } else {
          stream.point(to[0], to[1]);
        }
      }
  
      function corner(p, direction) {
        return abs(p[0] - x0) < epsilon$4 ? direction > 0 ? 0 : 3
            : abs(p[0] - x1) < epsilon$4 ? direction > 0 ? 2 : 1
            : abs(p[1] - y0) < epsilon$4 ? direction > 0 ? 1 : 0
            : direction > 0 ? 3 : 2; // abs(p[1] - y1) < epsilon
      }
  
      function compareIntersection(a, b) {
        return comparePoint(a.x, b.x);
      }
  
      function comparePoint(a, b) {
        var ca = corner(a, 1),
            cb = corner(b, 1);
        return ca !== cb ? ca - cb
            : ca === 0 ? b[1] - a[1]
            : ca === 1 ? a[0] - b[0]
            : ca === 2 ? a[1] - b[1]
            : b[0] - a[0];
      }
  
      return function(stream) {
        var activeStream = stream,
            bufferStream = clipBuffer(),
            segments,
            polygon,
            ring,
            x__, y__, v__, // first point
            x_, y_, v_, // previous point
            first,
            clean;
  
        var clipStream = {
          point: point,
          lineStart: lineStart,
          lineEnd: lineEnd,
          polygonStart: polygonStart,
          polygonEnd: polygonEnd
        };
  
        function point(x, y) {
          if (visible(x, y)) activeStream.point(x, y);
        }
  
        function polygonInside() {
          var winding = 0;
  
          for (var i = 0, n = polygon.length; i < n; ++i) {
            for (var ring = polygon[i], j = 1, m = ring.length, point = ring[0], a0, a1, b0 = point[0], b1 = point[1]; j < m; ++j) {
              a0 = b0, a1 = b1, point = ring[j], b0 = point[0], b1 = point[1];
              if (a1 <= y1) { if (b1 > y1 && (b0 - a0) * (y1 - a1) > (b1 - a1) * (x0 - a0)) ++winding; }
              else { if (b1 <= y1 && (b0 - a0) * (y1 - a1) < (b1 - a1) * (x0 - a0)) --winding; }
            }
          }
  
          return winding;
        }
  
        // Buffer geometry within a polygon and then clip it en masse.
        function polygonStart() {
          activeStream = bufferStream, segments = [], polygon = [], clean = true;
        }
  
        function polygonEnd() {
          var startInside = polygonInside(),
              cleanInside = clean && startInside,
              visible = (segments = merge(segments)).length;
          if (cleanInside || visible) {
            stream.polygonStart();
            if (cleanInside) {
              stream.lineStart();
              interpolate(null, null, 1, stream);
              stream.lineEnd();
            }
            if (visible) {
              clipPolygon(segments, compareIntersection, startInside, interpolate, stream);
            }
            stream.polygonEnd();
          }
          activeStream = stream, segments = polygon = ring = null;
        }
  
        function lineStart() {
          clipStream.point = linePoint;
          if (polygon) polygon.push(ring = []);
          first = true;
          v_ = false;
          x_ = y_ = NaN;
        }
  
        // TODO rather than special-case polygons, simply handle them separately.
        // Ideally, coincident intersection points should be jittered to avoid
        // clipping issues.
        function lineEnd() {
          if (segments) {
            linePoint(x__, y__);
            if (v__ && v_) bufferStream.rejoin();
            segments.push(bufferStream.result());
          }
          clipStream.point = point;
          if (v_) activeStream.lineEnd();
        }
  
        function linePoint(x, y) {
          var v = visible(x, y);
          if (polygon) ring.push([x, y]);
          if (first) {
            x__ = x, y__ = y, v__ = v;
            first = false;
            if (v) {
              activeStream.lineStart();
              activeStream.point(x, y);
            }
          } else {
            if (v && v_) activeStream.point(x, y);
            else {
              var a = [x_ = Math.max(clipMin, Math.min(clipMax, x_)), y_ = Math.max(clipMin, Math.min(clipMax, y_))],
                  b = [x = Math.max(clipMin, Math.min(clipMax, x)), y = Math.max(clipMin, Math.min(clipMax, y))];
              if (clipLine(a, b, x0, y0, x1, y1)) {
                if (!v_) {
                  activeStream.lineStart();
                  activeStream.point(a[0], a[1]);
                }
                activeStream.point(b[0], b[1]);
                if (!v) activeStream.lineEnd();
                clean = false;
              } else if (v) {
                activeStream.lineStart();
                activeStream.point(x, y);
                clean = false;
              }
            }
          }
          x_ = x, y_ = y, v_ = v;
        }
  
        return clipStream;
      };
    }
  
    function extent$1() {
      var x0 = 0,
          y0 = 0,
          x1 = 960,
          y1 = 500,
          cache,
          cacheStream,
          clip;
  
      return clip = {
        stream: function(stream) {
          return cache && cacheStream === stream ? cache : cache = clipExtent(x0, y0, x1, y1)(cacheStream = stream);
        },
        extent: function(_) {
          return arguments.length ? (x0 = +_[0][0], y0 = +_[0][1], x1 = +_[1][0], y1 = +_[1][1], cache = cacheStream = null, clip) : [[x0, y0], [x1, y1]];
        }
      };
    }
  
    var lengthSum = adder();
  var   lambda0$2;
  var   sinPhi0$1;
  var   cosPhi0$1;
    var lengthStream = {
      sphere: noop$2,
      point: noop$2,
      lineStart: lengthLineStart,
      lineEnd: noop$2,
      polygonStart: noop$2,
      polygonEnd: noop$2
    };
  
    function lengthLineStart() {
      lengthStream.point = lengthPointFirst;
      lengthStream.lineEnd = lengthLineEnd;
    }
  
    function lengthLineEnd() {
      lengthStream.point = lengthStream.lineEnd = noop$2;
    }
  
    function lengthPointFirst(lambda, phi) {
      lambda *= radians, phi *= radians;
      lambda0$2 = lambda, sinPhi0$1 = sin(phi), cosPhi0$1 = cos(phi);
      lengthStream.point = lengthPoint;
    }
  
    function lengthPoint(lambda, phi) {
      lambda *= radians, phi *= radians;
      var sinPhi = sin(phi),
          cosPhi = cos(phi),
          delta = abs(lambda - lambda0$2),
          cosDelta = cos(delta),
          sinDelta = sin(delta),
          x = cosPhi * sinDelta,
          y = cosPhi0$1 * sinPhi - sinPhi0$1 * cosPhi * cosDelta,
          z = sinPhi0$1 * sinPhi + cosPhi0$1 * cosPhi * cosDelta;
      lengthSum.add(atan2(sqrt$1(x * x + y * y), z));
      lambda0$2 = lambda, sinPhi0$1 = sinPhi, cosPhi0$1 = cosPhi;
    }
  
    function length$2(object) {
      lengthSum.reset();
      geoStream(object, lengthStream);
      return +lengthSum;
    }
  
    var coordinates = [null, null];
  var   object$1 = {type: "LineString", coordinates: coordinates};
    function distance(a, b) {
      coordinates[0] = a;
      coordinates[1] = b;
      return length$2(object$1);
    }
  
    function graticuleX(y0, y1, dy) {
      var y = range(y0, y1 - epsilon$4, dy).concat(y1);
      return function(x) { return y.map(function(y) { return [x, y]; }); };
    }
  
    function graticuleY(x0, x1, dx) {
      var x = range(x0, x1 - epsilon$4, dx).concat(x1);
      return function(y) { return x.map(function(x) { return [x, y]; }); };
    }
  
    function graticule() {
      var x1, x0, X1, X0,
          y1, y0, Y1, Y0,
          dx = 10, dy = dx, DX = 90, DY = 360,
          x, y, X, Y,
          precision = 2.5;
  
      function graticule() {
        return {type: "MultiLineString", coordinates: lines()};
      }
  
      function lines() {
        return range(ceil(X0 / DX) * DX, X1, DX).map(X)
            .concat(range(ceil(Y0 / DY) * DY, Y1, DY).map(Y))
            .concat(range(ceil(x0 / dx) * dx, x1, dx).filter(function(x) { return abs(x % DX) > epsilon$4; }).map(x))
            .concat(range(ceil(y0 / dy) * dy, y1, dy).filter(function(y) { return abs(y % DY) > epsilon$4; }).map(y));
      }
  
      graticule.lines = function() {
        return lines().map(function(coordinates) { return {type: "LineString", coordinates: coordinates}; });
      };
  
      graticule.outline = function() {
        return {
          type: "Polygon",
          coordinates: [
            X(X0).concat(
            Y(Y1).slice(1),
            X(X1).reverse().slice(1),
            Y(Y0).reverse().slice(1))
          ]
        };
      };
  
      graticule.extent = function(_) {
        if (!arguments.length) return graticule.extentMinor();
        return graticule.extentMajor(_).extentMinor(_);
      };
  
      graticule.extentMajor = function(_) {
        if (!arguments.length) return [[X0, Y0], [X1, Y1]];
        X0 = +_[0][0], X1 = +_[1][0];
        Y0 = +_[0][1], Y1 = +_[1][1];
        if (X0 > X1) _ = X0, X0 = X1, X1 = _;
        if (Y0 > Y1) _ = Y0, Y0 = Y1, Y1 = _;
        return graticule.precision(precision);
      };
  
      graticule.extentMinor = function(_) {
        if (!arguments.length) return [[x0, y0], [x1, y1]];
        x0 = +_[0][0], x1 = +_[1][0];
        y0 = +_[0][1], y1 = +_[1][1];
        if (x0 > x1) _ = x0, x0 = x1, x1 = _;
        if (y0 > y1) _ = y0, y0 = y1, y1 = _;
        return graticule.precision(precision);
      };
  
      graticule.step = function(_) {
        if (!arguments.length) return graticule.stepMinor();
        return graticule.stepMajor(_).stepMinor(_);
      };
  
      graticule.stepMajor = function(_) {
        if (!arguments.length) return [DX, DY];
        DX = +_[0], DY = +_[1];
        return graticule;
      };
  
      graticule.stepMinor = function(_) {
        if (!arguments.length) return [dx, dy];
        dx = +_[0], dy = +_[1];
        return graticule;
      };
  
      graticule.precision = function(_) {
        if (!arguments.length) return precision;
        precision = +_;
        x = graticuleX(y0, y1, 90);
        y = graticuleY(x0, x1, precision);
        X = graticuleX(Y0, Y1, 90);
        Y = graticuleY(X0, X1, precision);
        return graticule;
      };
  
      return graticule
          .extentMajor([[-180, -90 + epsilon$4], [180, 90 - epsilon$4]])
          .extentMinor([[-180, -80 - epsilon$4], [180, 80 + epsilon$4]]);
    }
  
    function interpolate$2(a, b) {
      var x0 = a[0] * radians,
          y0 = a[1] * radians,
          x1 = b[0] * radians,
          y1 = b[1] * radians,
          cy0 = cos(y0),
          sy0 = sin(y0),
          cy1 = cos(y1),
          sy1 = sin(y1),
          kx0 = cy0 * cos(x0),
          ky0 = cy0 * sin(x0),
          kx1 = cy1 * cos(x1),
          ky1 = cy1 * sin(x1),
          d = 2 * asin$1(sqrt$1(haversin(y1 - y0) + cy0 * cy1 * haversin(x1 - x0))),
          k = sin(d);
  
      var interpolate = d ? function(t) {
        var B = sin(t *= d) / k,
            A = sin(d - t) / k,
            x = A * kx0 + B * kx1,
            y = A * ky0 + B * ky1,
            z = A * sy0 + B * sy1;
        return [
          atan2(y, x) * degrees$1,
          atan2(z, sqrt$1(x * x + y * y)) * degrees$1
        ];
      } : function() {
        return [x0 * degrees$1, y0 * degrees$1];
      };
  
      interpolate.distance = d;
  
      return interpolate;
    }
  
    function identity$7(x) {
      return x;
    }
  
  var   areaSum$1 = adder();
  var   areaRingSum$1 = adder();
    var x00;
    var y00;
  var   x0$1;
  var   y0$1;
    var areaStream$1 = {
      point: noop$2,
      lineStart: noop$2,
      lineEnd: noop$2,
      polygonStart: function() {
        areaStream$1.lineStart = areaRingStart$1;
        areaStream$1.lineEnd = areaRingEnd$1;
      },
      polygonEnd: function() {
        areaStream$1.lineStart = areaStream$1.lineEnd = areaStream$1.point = noop$2;
        areaSum$1.add(abs(areaRingSum$1));
        areaRingSum$1.reset();
      },
      result: function() {
        var area = areaSum$1 / 2;
        areaSum$1.reset();
        return area;
      }
    };
  
    function areaRingStart$1() {
      areaStream$1.point = areaPointFirst$1;
    }
  
    function areaPointFirst$1(x, y) {
      areaStream$1.point = areaPoint$1;
      x00 = x0$1 = x, y00 = y0$1 = y;
    }
  
    function areaPoint$1(x, y) {
      areaRingSum$1.add(y0$1 * x - x0$1 * y);
      x0$1 = x, y0$1 = y;
    }
  
    function areaRingEnd$1() {
      areaPoint$1(x00, y00);
    }
  
  var   x0$2 = Infinity;
  var   y0$2 = x0$2;
    var x1 = -x0$2;
    var y1 = x1;
    var boundsStream$1 = {
      point: boundsPoint$1,
      lineStart: noop$2,
      lineEnd: noop$2,
      polygonStart: noop$2,
      polygonEnd: noop$2,
      result: function() {
        var bounds = [[x0$2, y0$2], [x1, y1]];
        x1 = y1 = -(y0$2 = x0$2 = Infinity);
        return bounds;
      }
    };
  
    function boundsPoint$1(x, y) {
      if (x < x0$2) x0$2 = x;
      if (x > x1) x1 = x;
      if (y < y0$2) y0$2 = y;
      if (y > y1) y1 = y;
    }
  
  var   X0$1 = 0;
  var   Y0$1 = 0;
  var   Z0$1 = 0;
  var   X1$1 = 0;
  var   Y1$1 = 0;
  var   Z1$1 = 0;
  var   X2$1 = 0;
  var   Y2$1 = 0;
  var   Z2$1 = 0;
  var   x00$1;
  var   y00$1;
  var   x0$3;
  var   y0$3;
    var centroidStream$1 = {
      point: centroidPoint$1,
      lineStart: centroidLineStart$1,
      lineEnd: centroidLineEnd$1,
      polygonStart: function() {
        centroidStream$1.lineStart = centroidRingStart$1;
        centroidStream$1.lineEnd = centroidRingEnd$1;
      },
      polygonEnd: function() {
        centroidStream$1.point = centroidPoint$1;
        centroidStream$1.lineStart = centroidLineStart$1;
        centroidStream$1.lineEnd = centroidLineEnd$1;
      },
      result: function() {
        var centroid = Z2$1 ? [X2$1 / Z2$1, Y2$1 / Z2$1]
            : Z1$1 ? [X1$1 / Z1$1, Y1$1 / Z1$1]
            : Z0$1 ? [X0$1 / Z0$1, Y0$1 / Z0$1]
            : [NaN, NaN];
        X0$1 = Y0$1 = Z0$1 =
        X1$1 = Y1$1 = Z1$1 =
        X2$1 = Y2$1 = Z2$1 = 0;
        return centroid;
      }
    };
  
    function centroidPoint$1(x, y) {
      X0$1 += x;
      Y0$1 += y;
      ++Z0$1;
    }
  
    function centroidLineStart$1() {
      centroidStream$1.point = centroidPointFirstLine;
    }
  
    function centroidPointFirstLine(x, y) {
      centroidStream$1.point = centroidPointLine;
      centroidPoint$1(x0$3 = x, y0$3 = y);
    }
  
    function centroidPointLine(x, y) {
      var dx = x - x0$3, dy = y - y0$3, z = sqrt$1(dx * dx + dy * dy);
      X1$1 += z * (x0$3 + x) / 2;
      Y1$1 += z * (y0$3 + y) / 2;
      Z1$1 += z;
      centroidPoint$1(x0$3 = x, y0$3 = y);
    }
  
    function centroidLineEnd$1() {
      centroidStream$1.point = centroidPoint$1;
    }
  
    function centroidRingStart$1() {
      centroidStream$1.point = centroidPointFirstRing;
    }
  
    function centroidRingEnd$1() {
      centroidPointRing(x00$1, y00$1);
    }
  
    function centroidPointFirstRing(x, y) {
      centroidStream$1.point = centroidPointRing;
      centroidPoint$1(x00$1 = x0$3 = x, y00$1 = y0$3 = y);
    }
  
    function centroidPointRing(x, y) {
      var dx = x - x0$3,
          dy = y - y0$3,
          z = sqrt$1(dx * dx + dy * dy);
  
      X1$1 += z * (x0$3 + x) / 2;
      Y1$1 += z * (y0$3 + y) / 2;
      Z1$1 += z;
  
      z = y0$3 * x - x0$3 * y;
      X2$1 += z * (x0$3 + x);
      Y2$1 += z * (y0$3 + y);
      Z2$1 += z * 3;
      centroidPoint$1(x0$3 = x, y0$3 = y);
    }
  
    function PathContext(context) {
      var pointRadius = 4.5;
  
      var stream = {
        point: point,
  
        // While inside a line, override point to moveTo then lineTo.
        lineStart: function() { stream.point = pointLineStart; },
        lineEnd: lineEnd,
  
        // While inside a polygon, override lineEnd to closePath.
        polygonStart: function() { stream.lineEnd = lineEndPolygon; },
        polygonEnd: function() { stream.lineEnd = lineEnd; stream.point = point; },
  
        pointRadius: function(_) {
          pointRadius = _;
          return stream;
        },
  
        result: noop$2
      };
  
      function point(x, y) {
        context.moveTo(x + pointRadius, y);
        context.arc(x, y, pointRadius, 0, tau$3);
      }
  
      function pointLineStart(x, y) {
        context.moveTo(x, y);
        stream.point = pointLine;
      }
  
      function pointLine(x, y) {
        context.lineTo(x, y);
      }
  
      function lineEnd() {
        stream.point = point;
      }
  
      function lineEndPolygon() {
        context.closePath();
      }
  
      return stream;
    }
  
    function PathString() {
      var pointCircle = circle$2(4.5),
          string = [];
  
      var stream = {
        point: point,
        lineStart: lineStart,
        lineEnd: lineEnd,
        polygonStart: function() {
          stream.lineEnd = lineEndPolygon;
        },
        polygonEnd: function() {
          stream.lineEnd = lineEnd;
          stream.point = point;
        },
        pointRadius: function(_) {
          pointCircle = circle$2(_);
          return stream;
        },
        result: function() {
          if (string.length) {
            var result = string.join("");
            string = [];
            return result;
          }
        }
      };
  
      function point(x, y) {
        string.push("M", x, ",", y, pointCircle);
      }
  
      function pointLineStart(x, y) {
        string.push("M", x, ",", y);
        stream.point = pointLine;
      }
  
      function pointLine(x, y) {
        string.push("L", x, ",", y);
      }
  
      function lineStart() {
        stream.point = pointLineStart;
      }
  
      function lineEnd() {
        stream.point = point;
      }
  
      function lineEndPolygon() {
        string.push("Z");
      }
  
      return stream;
    }
  
    function circle$2(radius) {
      return "m0," + radius
          + "a" + radius + "," + radius + " 0 1,1 0," + -2 * radius
          + "a" + radius + "," + radius + " 0 1,1 0," + 2 * radius
          + "z";
    }
  
    function index$3() {
      var pointRadius = 4.5,
          projection,
          projectionStream,
          context,
          contextStream;
  
      function path(object) {
        if (object) {
          if (typeof pointRadius === "function") contextStream.pointRadius(+pointRadius.apply(this, arguments));
          geoStream(object, projectionStream(contextStream));
        }
        return contextStream.result();
      }
  
      path.area = function(object) {
        geoStream(object, projectionStream(areaStream$1));
        return areaStream$1.result();
      };
  
      path.bounds = function(object) {
        geoStream(object, projectionStream(boundsStream$1));
        return boundsStream$1.result();
      };
  
      path.centroid = function(object) {
        geoStream(object, projectionStream(centroidStream$1));
        return centroidStream$1.result();
      };
  
      path.projection = function(_) {
        return arguments.length ? (projectionStream = (projection = _) == null ? identity$7 : _.stream, path) : projection;
      };
  
      path.context = function(_) {
        if (!arguments.length) return context;
        contextStream = (context = _) == null ? new PathString : new PathContext(_);
        if (typeof pointRadius !== "function") contextStream.pointRadius(pointRadius);
        return path;
      };
  
      path.pointRadius = function(_) {
        if (!arguments.length) return pointRadius;
        pointRadius = typeof _ === "function" ? _ : (contextStream.pointRadius(+_), +_);
        return path;
      };
  
      return path.projection(null).context(null);
    }
  
    var sum$2 = adder();
  
    function polygonContains(polygon, point) {
      var lambda = point[0],
          phi = point[1],
          normal = [sin(lambda), -cos(lambda), 0],
          angle = 0,
          winding = 0;
  
      sum$2.reset();
  
      for (var i = 0, n = polygon.length; i < n; ++i) {
        if (!(m = (ring = polygon[i]).length)) continue;
        var ring,
            m,
            point0 = ring[m - 1],
            lambda0 = point0[0],
            phi0 = point0[1] / 2 + quarterPi,
            sinPhi0 = sin(phi0),
            cosPhi0 = cos(phi0);
  
        for (var j = 0; j < m; ++j, lambda0 = lambda1, sinPhi0 = sinPhi1, cosPhi0 = cosPhi1, point0 = point1) {
          var point1 = ring[j],
              lambda1 = point1[0],
              phi1 = point1[1] / 2 + quarterPi,
              sinPhi1 = sin(phi1),
              cosPhi1 = cos(phi1),
              delta = lambda1 - lambda0,
              sign = delta >= 0 ? 1 : -1,
              absDelta = sign * delta,
              antimeridian = absDelta > pi$3,
              k = sinPhi0 * sinPhi1;
  
          sum$2.add(atan2(k * sign * sin(absDelta), cosPhi0 * cosPhi1 + k * cos(absDelta)));
          angle += antimeridian ? delta + sign * tau$3 : delta;
  
          // Are the longitudes either side of the point’s meridian (lambda),
          // and are the latitudes smaller than the parallel (phi)?
          if (antimeridian ^ lambda0 >= lambda ^ lambda1 >= lambda) {
            var arc = cartesianCross(cartesian(point0), cartesian(point1));
            cartesianNormalizeInPlace(arc);
            var intersection = cartesianCross(normal, arc);
            cartesianNormalizeInPlace(intersection);
            var phiArc = (antimeridian ^ delta >= 0 ? -1 : 1) * asin$1(intersection[2]);
            if (phi > phiArc || phi === phiArc && (arc[0] || arc[1])) {
              winding += antimeridian ^ delta >= 0 ? 1 : -1;
            }
          }
        }
      }
  
      // First, determine whether the South pole is inside or outside:
      //
      // It is inside if:
      // * the polygon winds around it in a clockwise direction.
      // * the polygon does not (cumulatively) wind around it, but has a negative
      //   (counter-clockwise) area.
      //
      // Second, count the (signed) number of times a segment crosses a lambda
      // from the point to the South pole.  If it is zero, then the point is the
      // same side as the South pole.
  
      return (angle < -epsilon$4 || angle < epsilon$4 && sum$2 < -epsilon$4) ^ (winding & 1);
    }
  
    function clip(pointVisible, clipLine, interpolate, start) {
      return function(rotate, sink) {
        var line = clipLine(sink),
            rotatedStart = rotate.invert(start[0], start[1]),
            ringBuffer = clipBuffer(),
            ringSink = clipLine(ringBuffer),
            polygonStarted = false,
            polygon,
            segments,
            ring;
  
        var clip = {
          point: point,
          lineStart: lineStart,
          lineEnd: lineEnd,
          polygonStart: function() {
            clip.point = pointRing;
            clip.lineStart = ringStart;
            clip.lineEnd = ringEnd;
            segments = [];
            polygon = [];
          },
          polygonEnd: function() {
            clip.point = point;
            clip.lineStart = lineStart;
            clip.lineEnd = lineEnd;
            segments = merge(segments);
            var startInside = polygonContains(polygon, rotatedStart);
            if (segments.length) {
              if (!polygonStarted) sink.polygonStart(), polygonStarted = true;
              clipPolygon(segments, compareIntersection, startInside, interpolate, sink);
            } else if (startInside) {
              if (!polygonStarted) sink.polygonStart(), polygonStarted = true;
              sink.lineStart();
              interpolate(null, null, 1, sink);
              sink.lineEnd();
            }
            if (polygonStarted) sink.polygonEnd(), polygonStarted = false;
            segments = polygon = null;
          },
          sphere: function() {
            sink.polygonStart();
            sink.lineStart();
            interpolate(null, null, 1, sink);
            sink.lineEnd();
            sink.polygonEnd();
          }
        };
  
        function point(lambda, phi) {
          var point = rotate(lambda, phi);
          if (pointVisible(lambda = point[0], phi = point[1])) sink.point(lambda, phi);
        }
  
        function pointLine(lambda, phi) {
          var point = rotate(lambda, phi);
          line.point(point[0], point[1]);
        }
  
        function lineStart() {
          clip.point = pointLine;
          line.lineStart();
        }
  
        function lineEnd() {
          clip.point = point;
          line.lineEnd();
        }
  
        function pointRing(lambda, phi) {
          ring.push([lambda, phi]);
          var point = rotate(lambda, phi);
          ringSink.point(point[0], point[1]);
        }
  
        function ringStart() {
          ringSink.lineStart();
          ring = [];
        }
  
        function ringEnd() {
          pointRing(ring[0][0], ring[0][1]);
          ringSink.lineEnd();
  
          var clean = ringSink.clean(),
              ringSegments = ringBuffer.result(),
              i, n = ringSegments.length, m,
              segment,
              point;
  
          ring.pop();
          polygon.push(ring);
          ring = null;
  
          if (!n) return;
  
          // No intersections.
          if (clean & 1) {
            segment = ringSegments[0];
            if ((m = segment.length - 1) > 0) {
              if (!polygonStarted) sink.polygonStart(), polygonStarted = true;
              sink.lineStart();
              for (i = 0; i < m; ++i) sink.point((point = segment[i])[0], point[1]);
              sink.lineEnd();
            }
            return;
          }
  
          // Rejoin connected segments.
          // TODO reuse ringBuffer.rejoin()?
          if (n > 1 && clean & 2) ringSegments.push(ringSegments.pop().concat(ringSegments.shift()));
  
          segments.push(ringSegments.filter(validSegment));
        }
  
        return clip;
      };
    }
  
    function validSegment(segment) {
      return segment.length > 1;
    }
  
    // Intersections are sorted along the clip edge. For both antimeridian cutting
    // and circle clipping, the same comparison is used.
    function compareIntersection(a, b) {
      return ((a = a.x)[0] < 0 ? a[1] - halfPi$2 - epsilon$4 : halfPi$2 - a[1])
           - ((b = b.x)[0] < 0 ? b[1] - halfPi$2 - epsilon$4 : halfPi$2 - b[1]);
    }
  
    var clipAntimeridian = clip(
      function() { return true; },
      clipAntimeridianLine,
      clipAntimeridianInterpolate,
      [-pi$3, -halfPi$2]
    );
  
    // Takes a line and cuts into visible segments. Return values: 0 - there were
    // intersections or the line was empty; 1 - no intersections; 2 - there were
    // intersections, and the first and last segments should be rejoined.
    function clipAntimeridianLine(stream) {
      var lambda0 = NaN,
          phi0 = NaN,
          sign0 = NaN,
          clean; // no intersections
  
      return {
        lineStart: function() {
          stream.lineStart();
          clean = 1;
        },
        point: function(lambda1, phi1) {
          var sign1 = lambda1 > 0 ? pi$3 : -pi$3,
              delta = abs(lambda1 - lambda0);
          if (abs(delta - pi$3) < epsilon$4) { // line crosses a pole
            stream.point(lambda0, phi0 = (phi0 + phi1) / 2 > 0 ? halfPi$2 : -halfPi$2);
            stream.point(sign0, phi0);
            stream.lineEnd();
            stream.lineStart();
            stream.point(sign1, phi0);
            stream.point(lambda1, phi0);
            clean = 0;
          } else if (sign0 !== sign1 && delta >= pi$3) { // line crosses antimeridian
            if (abs(lambda0 - sign0) < epsilon$4) lambda0 -= sign0 * epsilon$4; // handle degeneracies
            if (abs(lambda1 - sign1) < epsilon$4) lambda1 -= sign1 * epsilon$4;
            phi0 = clipAntimeridianIntersect(lambda0, phi0, lambda1, phi1);
            stream.point(sign0, phi0);
            stream.lineEnd();
            stream.lineStart();
            stream.point(sign1, phi0);
            clean = 0;
          }
          stream.point(lambda0 = lambda1, phi0 = phi1);
          sign0 = sign1;
        },
        lineEnd: function() {
          stream.lineEnd();
          lambda0 = phi0 = NaN;
        },
        clean: function() {
          return 2 - clean; // if intersections, rejoin first and last segments
        }
      };
    }
  
    function clipAntimeridianIntersect(lambda0, phi0, lambda1, phi1) {
      var cosPhi0,
          cosPhi1,
          sinLambda0Lambda1 = sin(lambda0 - lambda1);
      return abs(sinLambda0Lambda1) > epsilon$4
          ? atan((sin(phi0) * (cosPhi1 = cos(phi1)) * sin(lambda1)
              - sin(phi1) * (cosPhi0 = cos(phi0)) * sin(lambda0))
              / (cosPhi0 * cosPhi1 * sinLambda0Lambda1))
          : (phi0 + phi1) / 2;
    }
  
    function clipAntimeridianInterpolate(from, to, direction, stream) {
      var phi;
      if (from == null) {
        phi = direction * halfPi$2;
        stream.point(-pi$3, phi);
        stream.point(0, phi);
        stream.point(pi$3, phi);
        stream.point(pi$3, 0);
        stream.point(pi$3, -phi);
        stream.point(0, -phi);
        stream.point(-pi$3, -phi);
        stream.point(-pi$3, 0);
        stream.point(-pi$3, phi);
      } else if (abs(from[0] - to[0]) > epsilon$4) {
        var lambda = from[0] < to[0] ? pi$3 : -pi$3;
        phi = direction * lambda / 2;
        stream.point(-lambda, phi);
        stream.point(0, phi);
        stream.point(lambda, phi);
      } else {
        stream.point(to[0], to[1]);
      }
    }
  
    function clipCircle(radius, delta) {
      var cr = cos(radius),
          smallRadius = cr > 0,
          notHemisphere = abs(cr) > epsilon$4; // TODO optimise for this common case
  
      function interpolate(from, to, direction, stream) {
        circleStream(stream, radius, delta, direction, from, to);
      }
  
      function visible(lambda, phi) {
        return cos(lambda) * cos(phi) > cr;
      }
  
      // Takes a line and cuts into visible segments. Return values used for polygon
      // clipping: 0 - there were intersections or the line was empty; 1 - no
      // intersections 2 - there were intersections, and the first and last segments
      // should be rejoined.
      function clipLine(stream) {
        var point0, // previous point
            c0, // code for previous point
            v0, // visibility of previous point
            v00, // visibility of first point
            clean; // no intersections
        return {
          lineStart: function() {
            v00 = v0 = false;
            clean = 1;
          },
          point: function(lambda, phi) {
            var point1 = [lambda, phi],
                point2,
                v = visible(lambda, phi),
                c = smallRadius
                  ? v ? 0 : code(lambda, phi)
                  : v ? code(lambda + (lambda < 0 ? pi$3 : -pi$3), phi) : 0;
            if (!point0 && (v00 = v0 = v)) stream.lineStart();
            // Handle degeneracies.
            // TODO ignore if not clipping polygons.
            if (v !== v0) {
              point2 = intersect(point0, point1);
              if (pointEqual(point0, point2) || pointEqual(point1, point2)) {
                point1[0] += epsilon$4;
                point1[1] += epsilon$4;
                v = visible(point1[0], point1[1]);
              }
            }
            if (v !== v0) {
              clean = 0;
              if (v) {
                // outside going in
                stream.lineStart();
                point2 = intersect(point1, point0);
                stream.point(point2[0], point2[1]);
              } else {
                // inside going out
                point2 = intersect(point0, point1);
                stream.point(point2[0], point2[1]);
                stream.lineEnd();
              }
              point0 = point2;
            } else if (notHemisphere && point0 && smallRadius ^ v) {
              var t;
              // If the codes for two points are different, or are both zero,
              // and there this segment intersects with the small circle.
              if (!(c & c0) && (t = intersect(point1, point0, true))) {
                clean = 0;
                if (smallRadius) {
                  stream.lineStart();
                  stream.point(t[0][0], t[0][1]);
                  stream.point(t[1][0], t[1][1]);
                  stream.lineEnd();
                } else {
                  stream.point(t[1][0], t[1][1]);
                  stream.lineEnd();
                  stream.lineStart();
                  stream.point(t[0][0], t[0][1]);
                }
              }
            }
            if (v && (!point0 || !pointEqual(point0, point1))) {
              stream.point(point1[0], point1[1]);
            }
            point0 = point1, v0 = v, c0 = c;
          },
          lineEnd: function() {
            if (v0) stream.lineEnd();
            point0 = null;
          },
          // Rejoin first and last segments if there were intersections and the first
          // and last points were visible.
          clean: function() {
            return clean | ((v00 && v0) << 1);
          }
        };
      }
  
      // Intersects the great circle between a and b with the clip circle.
      function intersect(a, b, two) {
        var pa = cartesian(a),
            pb = cartesian(b);
  
        // We have two planes, n1.p = d1 and n2.p = d2.
        // Find intersection line p(t) = c1 n1 + c2 n2 + t (n1 ⨯ n2).
        var n1 = [1, 0, 0], // normal
            n2 = cartesianCross(pa, pb),
            n2n2 = cartesianDot(n2, n2),
            n1n2 = n2[0], // cartesianDot(n1, n2),
            determinant = n2n2 - n1n2 * n1n2;
  
        // Two polar points.
        if (!determinant) return !two && a;
  
        var c1 =  cr * n2n2 / determinant,
            c2 = -cr * n1n2 / determinant,
            n1xn2 = cartesianCross(n1, n2),
            A = cartesianScale(n1, c1),
            B = cartesianScale(n2, c2);
        cartesianAddInPlace(A, B);
  
        // Solve |p(t)|^2 = 1.
        var u = n1xn2,
            w = cartesianDot(A, u),
            uu = cartesianDot(u, u),
            t2 = w * w - uu * (cartesianDot(A, A) - 1);
  
        if (t2 < 0) return;
  
        var t = sqrt$1(t2),
            q = cartesianScale(u, (-w - t) / uu);
        cartesianAddInPlace(q, A);
        q = spherical(q);
  
        if (!two) return q;
  
        // Two intersection points.
        var lambda0 = a[0],
            lambda1 = b[0],
            phi0 = a[1],
            phi1 = b[1],
            z;
  
        if (lambda1 < lambda0) z = lambda0, lambda0 = lambda1, lambda1 = z;
  
        var delta = lambda1 - lambda0,
            polar = abs(delta - pi$3) < epsilon$4,
            meridian = polar || delta < epsilon$4;
  
        if (!polar && phi1 < phi0) z = phi0, phi0 = phi1, phi1 = z;
  
        // Check that the first point is between a and b.
        if (meridian
            ? polar
              ? phi0 + phi1 > 0 ^ q[1] < (abs(q[0] - lambda0) < epsilon$4 ? phi0 : phi1)
              : phi0 <= q[1] && q[1] <= phi1
            : delta > pi$3 ^ (lambda0 <= q[0] && q[0] <= lambda1)) {
          var q1 = cartesianScale(u, (-w + t) / uu);
          cartesianAddInPlace(q1, A);
          return [q, spherical(q1)];
        }
      }
  
      // Generates a 4-bit vector representing the location of a point relative to
      // the small circle's bounding box.
      function code(lambda, phi) {
        var r = smallRadius ? radius : pi$3 - radius,
            code = 0;
        if (lambda < -r) code |= 1; // left
        else if (lambda > r) code |= 2; // right
        if (phi < -r) code |= 4; // below
        else if (phi > r) code |= 8; // above
        return code;
      }
  
      return clip(visible, clipLine, interpolate, smallRadius ? [0, -radius] : [-pi$3, radius - pi$3]);
    }
  
    function transform$1(prototype) {
      return {
        stream: transform$2(prototype)
      };
    }
  
    function transform$2(prototype) {
      function T() {}
      var p = T.prototype = Object.create(Transform$1.prototype);
      for (var k in prototype) p[k] = prototype[k];
      return function(stream) {
        var t = new T;
        t.stream = stream;
        return t;
      };
    }
  
    function Transform$1() {}
  
    Transform$1.prototype = {
      point: function(x, y) { this.stream.point(x, y); },
      sphere: function() { this.stream.sphere(); },
      lineStart: function() { this.stream.lineStart(); },
      lineEnd: function() { this.stream.lineEnd(); },
      polygonStart: function() { this.stream.polygonStart(); },
      polygonEnd: function() { this.stream.polygonEnd(); }
    };
  
    function fit(project, extent, object) {
      var w = extent[1][0] - extent[0][0],
          h = extent[1][1] - extent[0][1],
          clip = project.clipExtent && project.clipExtent();
  
      project
          .scale(150)
          .translate([0, 0]);
  
      if (clip != null) project.clipExtent(null);
  
      geoStream(object, project.stream(boundsStream$1));
  
      var b = boundsStream$1.result(),
          k = Math.min(w / (b[1][0] - b[0][0]), h / (b[1][1] - b[0][1])),
          x = +extent[0][0] + (w - k * (b[1][0] + b[0][0])) / 2,
          y = +extent[0][1] + (h - k * (b[1][1] + b[0][1])) / 2;
  
      if (clip != null) project.clipExtent(clip);
  
      return project
          .scale(k * 150)
          .translate([x, y]);
    }
  
    function fitSize(project) {
      return function(size, object) {
        return fit(project, [[0, 0], size], object);
      };
    }
  
    function fitExtent(project) {
      return function(extent, object) {
        return fit(project, extent, object);
      };
    }
  
    var maxDepth = 16;
    var cosMinDistance = cos(30 * radians);
    // cos(minimum angular distance)
  
    function resample(project, delta2) {
      return +delta2 ? resample$1(project, delta2) : resampleNone(project);
    }
  
    function resampleNone(project) {
      return transform$2({
        point: function(x, y) {
          x = project(x, y);
          this.stream.point(x[0], x[1]);
        }
      });
    }
  
    function resample$1(project, delta2) {
  
      function resampleLineTo(x0, y0, lambda0, a0, b0, c0, x1, y1, lambda1, a1, b1, c1, depth, stream) {
        var dx = x1 - x0,
            dy = y1 - y0,
            d2 = dx * dx + dy * dy;
        if (d2 > 4 * delta2 && depth--) {
          var a = a0 + a1,
              b = b0 + b1,
              c = c0 + c1,
              m = sqrt$1(a * a + b * b + c * c),
              phi2 = asin$1(c /= m),
              lambda2 = abs(abs(c) - 1) < epsilon$4 || abs(lambda0 - lambda1) < epsilon$4 ? (lambda0 + lambda1) / 2 : atan2(b, a),
              p = project(lambda2, phi2),
              x2 = p[0],
              y2 = p[1],
              dx2 = x2 - x0,
              dy2 = y2 - y0,
              dz = dy * dx2 - dx * dy2;
          if (dz * dz / d2 > delta2 // perpendicular projected distance
              || abs((dx * dx2 + dy * dy2) / d2 - 0.5) > 0.3 // midpoint close to an end
              || a0 * a1 + b0 * b1 + c0 * c1 < cosMinDistance) { // angular distance
            resampleLineTo(x0, y0, lambda0, a0, b0, c0, x2, y2, lambda2, a /= m, b /= m, c, depth, stream);
            stream.point(x2, y2);
            resampleLineTo(x2, y2, lambda2, a, b, c, x1, y1, lambda1, a1, b1, c1, depth, stream);
          }
        }
      }
      return function(stream) {
        var lambda00, x00, y00, a00, b00, c00, // first point
            lambda0, x0, y0, a0, b0, c0; // previous point
  
        var resampleStream = {
          point: point,
          lineStart: lineStart,
          lineEnd: lineEnd,
          polygonStart: function() { stream.polygonStart(); resampleStream.lineStart = ringStart; },
          polygonEnd: function() { stream.polygonEnd(); resampleStream.lineStart = lineStart; }
        };
  
        function point(x, y) {
          x = project(x, y);
          stream.point(x[0], x[1]);
        }
  
        function lineStart() {
          x0 = NaN;
          resampleStream.point = linePoint;
          stream.lineStart();
        }
  
        function linePoint(lambda, phi) {
          var c = cartesian([lambda, phi]), p = project(lambda, phi);
          resampleLineTo(x0, y0, lambda0, a0, b0, c0, x0 = p[0], y0 = p[1], lambda0 = lambda, a0 = c[0], b0 = c[1], c0 = c[2], maxDepth, stream);
          stream.point(x0, y0);
        }
  
        function lineEnd() {
          resampleStream.point = point;
          stream.lineEnd();
        }
  
        function ringStart() {
          lineStart();
          resampleStream.point = ringPoint;
          resampleStream.lineEnd = ringEnd;
        }
  
        function ringPoint(lambda, phi) {
          linePoint(lambda00 = lambda, phi), x00 = x0, y00 = y0, a00 = a0, b00 = b0, c00 = c0;
          resampleStream.point = linePoint;
        }
  
        function ringEnd() {
          resampleLineTo(x0, y0, lambda0, a0, b0, c0, x00, y00, lambda00, a00, b00, c00, maxDepth, stream);
          resampleStream.lineEnd = lineEnd;
          lineEnd();
        }
  
        return resampleStream;
      };
    }
  
    var transformRadians = transform$2({
      point: function(x, y) {
        this.stream.point(x * radians, y * radians);
      }
    });
  
    function projection(project) {
      return projectionMutator(function() { return project; })();
    }
  
    function projectionMutator(projectAt) {
      var project,
          k = 150, // scale
          x = 480, y = 250, // translate
          dx, dy, lambda = 0, phi = 0, // center
          deltaLambda = 0, deltaPhi = 0, deltaGamma = 0, rotate, projectRotate, // rotate
          theta = null, preclip = clipAntimeridian, // clip angle
          x0 = null, y0, x1, y1, postclip = identity$7, // clip extent
          delta2 = 0.5, projectResample = resample(projectTransform, delta2), // precision
          cache,
          cacheStream;
  
      function projection(point) {
        point = projectRotate(point[0] * radians, point[1] * radians);
        return [point[0] * k + dx, dy - point[1] * k];
      }
  
      function invert(point) {
        point = projectRotate.invert((point[0] - dx) / k, (dy - point[1]) / k);
        return point && [point[0] * degrees$1, point[1] * degrees$1];
      }
  
      function projectTransform(x, y) {
        return x = project(x, y), [x[0] * k + dx, dy - x[1] * k];
      }
  
      projection.stream = function(stream) {
        return cache && cacheStream === stream ? cache : cache = transformRadians(preclip(rotate, projectResample(postclip(cacheStream = stream))));
      };
  
      projection.clipAngle = function(_) {
        return arguments.length ? (preclip = +_ ? clipCircle(theta = _ * radians, 6 * radians) : (theta = null, clipAntimeridian), reset()) : theta * degrees$1;
      };
  
      projection.clipExtent = function(_) {
        return arguments.length ? (postclip = _ == null ? (x0 = y0 = x1 = y1 = null, identity$7) : clipExtent(x0 = +_[0][0], y0 = +_[0][1], x1 = +_[1][0], y1 = +_[1][1]), reset()) : x0 == null ? null : [[x0, y0], [x1, y1]];
      };
  
      projection.scale = function(_) {
        return arguments.length ? (k = +_, recenter()) : k;
      };
  
      projection.translate = function(_) {
        return arguments.length ? (x = +_[0], y = +_[1], recenter()) : [x, y];
      };
  
      projection.center = function(_) {
        return arguments.length ? (lambda = _[0] % 360 * radians, phi = _[1] % 360 * radians, recenter()) : [lambda * degrees$1, phi * degrees$1];
      };
  
      projection.rotate = function(_) {
        return arguments.length ? (deltaLambda = _[0] % 360 * radians, deltaPhi = _[1] % 360 * radians, deltaGamma = _.length > 2 ? _[2] % 360 * radians : 0, recenter()) : [deltaLambda * degrees$1, deltaPhi * degrees$1, deltaGamma * degrees$1];
      };
  
      projection.precision = function(_) {
        return arguments.length ? (projectResample = resample(projectTransform, delta2 = _ * _), reset()) : sqrt$1(delta2);
      };
  
      projection.fitExtent = fitExtent(projection);
  
      projection.fitSize = fitSize(projection);
  
      function recenter() {
        projectRotate = compose(rotate = rotateRadians(deltaLambda, deltaPhi, deltaGamma), project);
        var center = project(lambda, phi);
        dx = x - center[0] * k;
        dy = y + center[1] * k;
        return reset();
      }
  
      function reset() {
        cache = cacheStream = null;
        return projection;
      }
  
      return function() {
        project = projectAt.apply(this, arguments);
        projection.invert = project.invert && invert;
        return recenter();
      };
    }
  
    function conicProjection(projectAt) {
      var phi0 = 0,
          phi1 = pi$3 / 3,
          m = projectionMutator(projectAt),
          p = m(phi0, phi1);
  
      p.parallels = function(_) {
        return arguments.length ? m(phi0 = _[0] * radians, phi1 = _[1] * radians) : [phi0 * degrees$1, phi1 * degrees$1];
      };
  
      return p;
    }
  
    function conicEqualAreaRaw(y0, y1) {
      var sy0 = sin(y0),
          n = (sy0 + sin(y1)) / 2,
          c = 1 + sy0 * (2 * n - sy0),
          r0 = sqrt$1(c) / n;
  
      function project(x, y) {
        var r = sqrt$1(c - 2 * n * sin(y)) / n;
        return [r * sin(x *= n), r0 - r * cos(x)];
      }
  
      project.invert = function(x, y) {
        var r0y = r0 - y;
        return [atan2(x, r0y) / n, asin$1((c - (x * x + r0y * r0y) * n * n) / (2 * n))];
      };
  
      return project;
    }
  
    function conicEqualArea() {
      return conicProjection(conicEqualAreaRaw)
          .scale(155.424)
          .center([0, 33.6442]);
    }
  
    function albers() {
      return conicEqualArea()
          .parallels([29.5, 45.5])
          .scale(1070)
          .translate([480, 250])
          .rotate([96, 0])
          .center([-0.6, 38.7]);
    }
  
    // The projections must have mutually exclusive clip regions on the sphere,
    // as this will avoid emitting interleaving lines and polygons.
    function multiplex(streams) {
      var n = streams.length;
      return {
        point: function(x, y) { var i = -1; while (++i < n) streams[i].point(x, y); },
        sphere: function() { var i = -1; while (++i < n) streams[i].sphere(); },
        lineStart: function() { var i = -1; while (++i < n) streams[i].lineStart(); },
        lineEnd: function() { var i = -1; while (++i < n) streams[i].lineEnd(); },
        polygonStart: function() { var i = -1; while (++i < n) streams[i].polygonStart(); },
        polygonEnd: function() { var i = -1; while (++i < n) streams[i].polygonEnd(); }
      };
    }
  
    // A composite projection for the United States, configured by default for
    // 960×500. The projection also works quite well at 960×600 if you change the
    // scale to 1285 and adjust the translate accordingly. The set of standard
    // parallels for each region comes from USGS, which is published here:
    // http://egsc.usgs.gov/isb/pubs/MapProjections/projections.html#albers
    function albersUsa() {
      var cache,
          cacheStream,
          lower48 = albers(), lower48Point,
          alaska = conicEqualArea().rotate([154, 0]).center([-2, 58.5]).parallels([55, 65]), alaskaPoint, // EPSG:3338
          hawaii = conicEqualArea().rotate([157, 0]).center([-3, 19.9]).parallels([8, 18]), hawaiiPoint, // ESRI:102007
          point, pointStream = {point: function(x, y) { point = [x, y]; }};
  
      function albersUsa(coordinates) {
        var x = coordinates[0], y = coordinates[1];
        return point = null,
            (lower48Point.point(x, y), point)
            || (alaskaPoint.point(x, y), point)
            || (hawaiiPoint.point(x, y), point);
      }
  
      albersUsa.invert = function(coordinates) {
        var k = lower48.scale(),
            t = lower48.translate(),
            x = (coordinates[0] - t[0]) / k,
            y = (coordinates[1] - t[1]) / k;
        return (y >= 0.120 && y < 0.234 && x >= -0.425 && x < -0.214 ? alaska
            : y >= 0.166 && y < 0.234 && x >= -0.214 && x < -0.115 ? hawaii
            : lower48).invert(coordinates);
      };
  
      albersUsa.stream = function(stream) {
        return cache && cacheStream === stream ? cache : cache = multiplex([lower48.stream(cacheStream = stream), alaska.stream(stream), hawaii.stream(stream)]);
      };
  
      albersUsa.precision = function(_) {
        if (!arguments.length) return lower48.precision();
        lower48.precision(_), alaska.precision(_), hawaii.precision(_);
        return albersUsa;
      };
  
      albersUsa.scale = function(_) {
        if (!arguments.length) return lower48.scale();
        lower48.scale(_), alaska.scale(_ * 0.35), hawaii.scale(_);
        return albersUsa.translate(lower48.translate());
      };
  
      albersUsa.translate = function(_) {
        if (!arguments.length) return lower48.translate();
        var k = lower48.scale(), x = +_[0], y = +_[1];
  
        lower48Point = lower48
            .translate(_)
            .clipExtent([[x - 0.455 * k, y - 0.238 * k], [x + 0.455 * k, y + 0.238 * k]])
            .stream(pointStream);
  
        alaskaPoint = alaska
            .translate([x - 0.307 * k, y + 0.201 * k])
            .clipExtent([[x - 0.425 * k + epsilon$4, y + 0.120 * k + epsilon$4], [x - 0.214 * k - epsilon$4, y + 0.234 * k - epsilon$4]])
            .stream(pointStream);
  
        hawaiiPoint = hawaii
            .translate([x - 0.205 * k, y + 0.212 * k])
            .clipExtent([[x - 0.214 * k + epsilon$4, y + 0.166 * k + epsilon$4], [x - 0.115 * k - epsilon$4, y + 0.234 * k - epsilon$4]])
            .stream(pointStream);
  
        return albersUsa;
      };
  
      albersUsa.fitExtent = fitExtent(albersUsa);
  
      albersUsa.fitSize = fitSize(albersUsa);
  
      return albersUsa.scale(1070);
    }
  
    function azimuthalRaw(scale) {
      return function(x, y) {
        var cx = cos(x),
            cy = cos(y),
            k = scale(cx * cy);
        return [
          k * cy * sin(x),
          k * sin(y)
        ];
      }
    }
  
    function azimuthalInvert(angle) {
      return function(x, y) {
        var z = sqrt$1(x * x + y * y),
            c = angle(z),
            sc = sin(c),
            cc = cos(c);
        return [
          atan2(x * sc, z * cc),
          asin$1(z && y * sc / z)
        ];
      }
    }
  
    var azimuthalEqualAreaRaw = azimuthalRaw(function(cxcy) {
      return sqrt$1(2 / (1 + cxcy));
    });
  
    azimuthalEqualAreaRaw.invert = azimuthalInvert(function(z) {
      return 2 * asin$1(z / 2);
    });
  
    function azimuthalEqualArea() {
      return projection(azimuthalEqualAreaRaw)
          .scale(124.75)
          .clipAngle(180 - 1e-3);
    }
  
    var azimuthalEquidistantRaw = azimuthalRaw(function(c) {
      return (c = acos(c)) && c / sin(c);
    });
  
    azimuthalEquidistantRaw.invert = azimuthalInvert(function(z) {
      return z;
    });
  
    function azimuthalEquidistant() {
      return projection(azimuthalEquidistantRaw)
          .scale(79.4188)
          .clipAngle(180 - 1e-3);
    }
  
    function mercatorRaw(lambda, phi) {
      return [lambda, log$1(tan((halfPi$2 + phi) / 2))];
    }
  
    mercatorRaw.invert = function(x, y) {
      return [x, 2 * atan(exp(y)) - halfPi$2];
    };
  
    function mercator() {
      return mercatorProjection(mercatorRaw)
          .scale(961 / tau$3);
    }
  
    function mercatorProjection(project) {
      var m = projection(project),
          scale = m.scale,
          translate = m.translate,
          clipExtent = m.clipExtent,
          clipAuto;
  
      m.scale = function(_) {
        return arguments.length ? (scale(_), clipAuto && m.clipExtent(null), m) : scale();
      };
  
      m.translate = function(_) {
        return arguments.length ? (translate(_), clipAuto && m.clipExtent(null), m) : translate();
      };
  
      m.clipExtent = function(_) {
        if (!arguments.length) return clipAuto ? null : clipExtent();
        if (clipAuto = _ == null) {
          var k = pi$3 * scale(),
              t = translate();
          _ = [[t[0] - k, t[1] - k], [t[0] + k, t[1] + k]];
        }
        clipExtent(_);
        return m;
      };
  
      return m.clipExtent(null);
    }
  
    function tany(y) {
      return tan((halfPi$2 + y) / 2);
    }
  
    function conicConformalRaw(y0, y1) {
      var cy0 = cos(y0),
          n = y0 === y1 ? sin(y0) : log$1(cy0 / cos(y1)) / log$1(tany(y1) / tany(y0)),
          f = cy0 * pow$1(tany(y0), n) / n;
  
      if (!n) return mercatorRaw;
  
      function project(x, y) {
        if (f > 0) { if (y < -halfPi$2 + epsilon$4) y = -halfPi$2 + epsilon$4; }
        else { if (y > halfPi$2 - epsilon$4) y = halfPi$2 - epsilon$4; }
        var r = f / pow$1(tany(y), n);
        return [r * sin(n * x), f - r * cos(n * x)];
      }
  
      project.invert = function(x, y) {
        var fy = f - y, r = sign$1(n) * sqrt$1(x * x + fy * fy);
        return [atan2(x, fy) / n, 2 * atan(pow$1(f / r, 1 / n)) - halfPi$2];
      };
  
      return project;
    }
  
    function conicConformal() {
      return conicProjection(conicConformalRaw)
          .scale(109.5)
          .parallels([30, 30]);
    }
  
    function equirectangularRaw(lambda, phi) {
      return [lambda, phi];
    }
  
    equirectangularRaw.invert = equirectangularRaw;
  
    function equirectangular() {
      return projection(equirectangularRaw)
          .scale(152.63);
    }
  
    function conicEquidistantRaw(y0, y1) {
      var cy0 = cos(y0),
          n = y0 === y1 ? sin(y0) : (cy0 - cos(y1)) / (y1 - y0),
          g = cy0 / n + y0;
  
      if (abs(n) < epsilon$4) return equirectangularRaw;
  
      function project(x, y) {
        var gy = g - y, nx = n * x;
        return [gy * sin(nx), g - gy * cos(nx)];
      }
  
      project.invert = function(x, y) {
        var gy = g - y;
        return [atan2(x, gy) / n, g - sign$1(n) * sqrt$1(x * x + gy * gy)];
      };
  
      return project;
    }
  
    function conicEquidistant() {
      return conicProjection(conicEquidistantRaw)
          .scale(131.154)
          .center([0, 13.9389]);
    }
  
    function gnomonicRaw(x, y) {
      var cy = cos(y), k = cos(x) * cy;
      return [cy * sin(x) / k, sin(y) / k];
    }
  
    gnomonicRaw.invert = azimuthalInvert(atan);
  
    function gnomonic() {
      return projection(gnomonicRaw)
          .scale(144.049)
          .clipAngle(60);
    }
  
    function orthographicRaw(x, y) {
      return [cos(y) * sin(x), sin(y)];
    }
  
    orthographicRaw.invert = azimuthalInvert(asin$1);
  
    function orthographic() {
      return projection(orthographicRaw)
          .scale(249.5)
          .clipAngle(90 + epsilon$4);
    }
  
    function stereographicRaw(x, y) {
      var cy = cos(y), k = 1 + cos(x) * cy;
      return [cy * sin(x) / k, sin(y) / k];
    }
  
    stereographicRaw.invert = azimuthalInvert(function(z) {
      return 2 * atan(z);
    });
  
    function stereographic() {
      return projection(stereographicRaw)
          .scale(250)
          .clipAngle(142);
    }
  
    function transverseMercatorRaw(lambda, phi) {
      return [log$1(tan((halfPi$2 + phi) / 2)), -lambda];
    }
  
    transverseMercatorRaw.invert = function(x, y) {
      return [-y, 2 * atan(exp(x)) - halfPi$2];
    };
  
    function transverseMercator() {
      var m = mercatorProjection(transverseMercatorRaw),
          center = m.center,
          rotate = m.rotate;
  
      m.center = function(_) {
        return arguments.length ? center([-_[1], _[0]]) : (_ = center(), [_[1], -_[0]]);
      };
  
      m.rotate = function(_) {
        return arguments.length ? rotate([_[0], _[1], _.length > 2 ? _[2] + 90 : 90]) : (_ = rotate(), [_[0], _[1], _[2] - 90]);
      };
  
      return rotate([0, 0, 90])
          .scale(159.155);
    }
  
    function attrsFunction(selection, map) {
      return selection.each(function() {
        var x = map.apply(this, arguments), s = select(this);
        for (var name in x) s.attr(name, x[name]);
      });
    }
  
    function attrsObject(selection, map) {
      for (var name in map) selection.attr(name, map[name]);
      return selection;
    }
  
    function selection_attrs(map) {
      return (typeof map === "function" ? attrsFunction : attrsObject)(this, map);
    }
  
    function stylesFunction(selection, map, priority) {
      return selection.each(function() {
        var x = map.apply(this, arguments), s = select(this);
        for (var name in x) s.style(name, x[name], priority);
      });
    }
  
    function stylesObject(selection, map, priority) {
      for (var name in map) selection.style(name, map[name], priority);
      return selection;
    }
  
    function selection_styles(map, priority) {
      return (typeof map === "function" ? stylesFunction : stylesObject)(this, map, priority == null ? "" : priority);
    }
  
    function propertiesFunction(selection, map) {
      return selection.each(function() {
        var x = map.apply(this, arguments), s = select(this);
        for (var name in x) s.property(name, x[name]);
      });
    }
  
    function propertiesObject(selection, map) {
      for (var name in map) selection.property(name, map[name]);
      return selection;
    }
  
    function selection_properties(map) {
      return (typeof map === "function" ? propertiesFunction : propertiesObject)(this, map);
    }
  
    function attrsFunction$1(transition, map) {
      return transition.each(function() {
        var x = map.apply(this, arguments), t = select(this).transition(transition);
        for (var name in x) t.attr(name, x[name]);
      });
    }
  
    function attrsObject$1(transition, map) {
      for (var name in map) transition.attr(name, map[name]);
      return transition;
    }
  
    function transition_attrs(map) {
      return (typeof map === "function" ? attrsFunction$1 : attrsObject$1)(this, map);
    }
  
    function stylesFunction$1(transition, map, priority) {
      return transition.each(function() {
        var x = map.apply(this, arguments), t = select(this).transition(transition);
        for (var name in x) t.style(name, x[name], priority);
      });
    }
  
    function stylesObject$1(transition, map, priority) {
      for (var name in map) transition.style(name, map[name], priority);
      return transition;
    }
  
    function transition_styles(map, priority) {
      return (typeof map === "function" ? stylesFunction$1 : stylesObject$1)(this, map, priority == null ? "" : priority);
    }
  
    selection.prototype.attrs = selection_attrs;
    selection.prototype.styles = selection_styles;
    selection.prototype.properties = selection_properties;
    transition.prototype.attrs = transition_attrs;
    transition.prototype.styles = transition_styles;
  
    function translateSelection(xy) {
      return this.attr('transform', function(d,i) {
        return 'translate('+[typeof xy == 'function' ? xy.call(this, d,i) : xy]+')';
      });
    };
  
    function parseAttributes(name) {
      if (typeof name === "string") {
        var attr = {},
          parts = name.split(/([\.#])/g), p;
          name = parts.shift();
        while ((p = parts.shift())) {
          if (p == '.') attr['class'] = attr['class'] ? attr['class'] + ' ' + parts.shift() : parts.shift();
          else if (p == '#') attr.id = parts.shift();
        }
        return {tag: name, attr: attr};
      }
      return name;
    }
  
    function append(name) {
      var n = parseAttributes(name), s;
      name = creator(n.tag);
      s = this.select(function() {
        return this.appendChild(name.apply(this, arguments));
      });
  
      //attrs not provided by default in v4
      for (var key in n.attr) { s.attr(key, n.attr[key]) }
      return s;
    };
  
    function selectAppend(name) {
      var select = selector(name),
         n = parseAttributes(name), s;
  
      name = creator(n.tag);
  
      s = this.select(function() {
        return select.apply(this, arguments)
            || this.appendChild(name.apply(this, arguments));
      });
  
      //attrs not provided by default in v4
      for (var key in n.attr) { s.attr(key, n.attr[key]) }
      return s;
    };
  
    function tspans(lines, lh) {
      return this.selectAll('tspan')
          .data(lines).enter()
        .append('tspan')
          .text(function(d) { return d; })
          .attr('x', 0)
          .attr('dy', function(d, i) { return i ? lh || 15 : 0; });
    };
  
    function appendMany(data, name){
      return this.selectAll(null).data(data).enter().append(name);
    };
  
    function at(name, value) {
      if (typeof(name) == 'object'){
        for (var key in name){
          this.attr(key.replace(/([a-z\d])([A-Z])/g, '$1-$2').toLowerCase(), name[key]) 
        }
        return this
      } else{
        return arguments.length == 1 ? this.attr(name) : this.attr(name, value)
      }
    };
  
    function f(){
      var functions = arguments
      
      //convert all string arguments into field accessors
      var i = 0, l = functions.length
      while (i < l) {
        if (typeof(functions[i]) === 'string' || typeof(functions[i]) === 'number'){
          functions[i] = (function(str){ return function(d){ return d[str] } })(functions[i])
        }
        i++
      }
  
       //return composition of functions
      return function(d) {
        var i=0, l = functions.length
        while (i++ < l) d = functions[i-1].call(this, d)
        return d
      }
    }
  
    f.not = function(d){ return !d }
    f.run = function(d){ return d() }
    f.objToFn = function(obj, defaultVal){
      if (arguments.length == 1) defaultVal = undefined
  
      return function(str){
        return typeof(obj[str]) !== undefined ? obj[str] : defaultVal }
    }
  
    function st(name, value) {
      if (typeof(name) == 'object'){
        for (var key in name){
          addStyle(this, key, name[key])
        }
        return this
      } else{
        return arguments.length == 1 ? this.style(name) : addStyle(this, name, value)
      }
  
  
      function addStyle(sel, style, value){
        var style = style.replace(/([a-z\d])([A-Z])/g, '$1-$2').toLowerCase()
  
        var pxStyles = 'top left bottom right padding-top padding-left padding-bottom padding-right border-top b-width border-left-width border-botto-width m border-right-width  margin-top margin-left margin-bottom margin-right font-size width height stroke-width line-height margin padding border max-width min-width'
  
        if (~pxStyles.indexOf(style) ){
          sel.style(style, typeof value == 'function' ? f(value, addPx) : addPx(value))
        } else{
          sel.style(style, value)
        }
  
        return sel
      } 
  
      function addPx(d){ return d.match ? d : d + 'px' }
    };
  
    function wordwrap(line, maxCharactersPerLine) {
      var w = line.split(' '),
        lines = [],
        words = [],
        maxChars = maxCharactersPerLine || 40,
        l = 0;
  
      w.forEach(function(d) {
        if (l+d.length > maxChars) {
          lines.push(words.join(' '));
          words.length = 0;
          l = 0;
        }
        l += d.length;
        words.push(d);
      });
      if (words.length) {
        lines.push(words.join(' '));
      }
      return lines.filter(function(d){ return d != '' });
    };
  
    function ascendingKey(key) {
      return typeof key == 'function' ? function (a, b) {
        return key(a) < key(b) ? -1 : key(a) > key(b) ? 1 : key(a) >= key(b) ? 0 : NaN;
      } : function (a, b) {
        return a[key] < b[key] ? -1 : a[key] > b[key] ? 1 : a[key] >= b[key] ? 0 : NaN;
      };
    };
  
    function descendingKey(key) {
      return typeof key == 'function' ? function (a, b) {
        return key(b) < key(a) ? -1 : key(b) > key(a) ? 1 : key(b) >= key(a) ? 0 : NaN;
      } : function (a, b) {
        return b[key] < a[key] ? -1 : b[key] > a[key] ? 1 : b[key] >= a[key] ? 0 : NaN;
      };
    };
  
    function conventions(c){
      c = c || {}
  
      c.margin = c.margin || {top: 20, right: 20, bottom: 20, left: 20}
      ;['top', 'right', 'bottom', 'left'].forEach(function(d){
        if (!c.margin[d] && c.margin[d] != 0) c.margin[d] = 20 
      })
  
      c.width  = c.width  || c.totalWidth  - c.margin.left - c.margin.right || 900
      c.height = c.height || c.totalHeight - c.margin.top - c.margin.bottom || 460
  
      c.totalWidth = c.width + c.margin.left + c.margin.right
      c.totalHeight = c.height + c.margin.top + c.margin.bottom
  
      c.parentSel = c.parentSel || select('body')
  
      c.rootsvg = c.parentSel.append('svg')
  
      c.svg = c.rootsvg
          .attr('width', c.totalWidth)
          .attr('height', c.totalHeight)
        .append('g')
          .attr('transform', 'translate(' + c.margin.left + ',' + c.margin.top + ')')
  
      c.x = c.x || linear$2().range([0, c.width])
      c.y = c.y || linear$2().range([c.height, 0])
  
      c.xAxis = c.xAxis || axisBottom().scale(c.x)
      c.yAxis = c.yAxis || axisLeft().scale(c.y)
  
      c.drawAxis = function(){
        c.svg.append('g')
            .attr('class', 'x axis')
            .attr('transform', 'translate(0,' + c.height + ')')
            .call(c.xAxis);
  
        c.svg.append('g')
            .attr('class', 'y axis')
            .call(c.yAxis);
      }
      
      return c
    }
  
    function attachTooltip(sel, tooltipSel, fieldFns){
      if (!sel.size()) return
  
      tooltipSel = tooltipSel || select('.tooltip')
  
      sel 
          .on('mouseover.attachTooltip', ttDisplay)
          .on('mousemove.attachTooltip', ttMove)
          .on('mouseout.attachTooltip',  ttHide)
          .on('click.attachTooltip', function(d){ console.log(d) })
  
      var d = sel.datum()
      fieldFns = fieldFns || d3keys(d)
          .filter(function(str){
            return (typeof d[str] != 'object') && (d[str] != 'array')
          })
          .map(function(str){
            return function(d){ return str + ': <b>' + d[str] + '</b>'} })
  
      function ttDisplay(d){
        tooltipSel
            .classed('tooltip-hidden', false)
            .html('')
          .appendMany(fieldFns, 'div')
            .html(function(fn){ return fn(d) })
  
        select(this).classed('tooltipped', true)
      }
  
      function ttMove(d){
        var tt = tooltipSel
        if (!tt.size()) return
        var e = exports.event,
            x = e.clientX,
            y = e.clientY,
            n = tt.node(),
            nBB = n.getBoundingClientRect(),
            doctop = (window.scrollY)? window.scrollY : (document.documentElement && document.documentElement.scrollTop)? document.documentElement.scrollTop : document.body.scrollTop,
            topPos = y+doctop-nBB.height-18;
  
        tt.style('top', (topPos < 0 ? 18 + y : topPos)+'px');
        tt.style('left', Math.min(Math.max(20, (x-nBB.width/2)), window.innerWidth - nBB.width - 20)+'px');
      }
  
      function ttHide(d){
        tooltipSel.classed('tooltip-hidden', true);
  
        selectAll('.tooltipped').classed('tooltipped', false)
      }
    }
  
    function loadData(files, cb){
      var q = queue()
      files.forEach(function(d){
        var type = d.split('.').reverse()[0]
  
        var loadFn = {csv: csv$1, tsv: tsv$1, json: json}[type]
        if (!loadFn) return cb(new Error('Invalid type', d))
        q.defer(loadFn, d) 
      })
      q.awaitAll(cb)
    }
  
    function nestBy(array, key){
      return nest().key(key).entries(array).map(function(d){
        d.values.key = d.key
        return d.values
      })
    }
  
    function round(n, p) {
      return p ? Math.round(n * (p = Math.pow(10, p))) / p : Math.round(n);
    };
  
    selection.prototype.translate = translateSelection
    selection.prototype.append = append
    selection.prototype.selectAppend = selectAppend
    selection.prototype.tspans = tspans
    selection.prototype.appendMany = appendMany
    selection.prototype.at = at
    selection.prototype.st = st
    selection.prototype.prop = selection.prototype.property
  
    exports.bisect = bisectRight;
    exports.bisectRight = bisectRight;
    exports.bisectLeft = bisectLeft;
    exports.ascending = ascending;
    exports.bisector = bisector;
    exports.descending = descending;
    exports.deviation = deviation;
    exports.extent = extent;
    exports.histogram = histogram;
    exports.thresholdFreedmanDiaconis = freedmanDiaconis;
    exports.thresholdScott = scott;
    exports.thresholdSturges = sturges;
    exports.max = max;
    exports.mean = mean;
    exports.median = median;
    exports.merge = merge;
    exports.min = min;
    exports.pairs = pairs;
    exports.permute = permute;
    exports.quantile = threshold;
    exports.range = range;
    exports.scan = scan;
    exports.shuffle = shuffle;
    exports.sum = sum;
    exports.ticks = ticks;
    exports.tickStep = tickStep;
    exports.transpose = transpose;
    exports.variance = variance;
    exports.zip = zip;
    exports.entries = entries;
    exports.keys = d3keys;
    exports.values = values;
    exports.map = map$1;
    exports.set = set;
    exports.nest = nest;
    exports.randomUniform = uniform;
    exports.randomNormal = normal;
    exports.randomLogNormal = logNormal;
    exports.randomBates = bates;
    exports.randomIrwinHall = irwinHall;
    exports.randomExponential = exponential;
    exports.easeLinear = linear;
    exports.easeQuad = quadInOut;
    exports.easeQuadIn = quadIn;
    exports.easeQuadOut = quadOut;
    exports.easeQuadInOut = quadInOut;
    exports.easeCubic = easeCubicInOut;
    exports.easeCubicIn = cubicIn;
    exports.easeCubicOut = cubicOut;
    exports.easeCubicInOut = easeCubicInOut;
    exports.easePoly = polyInOut;
    exports.easePolyIn = polyIn;
    exports.easePolyOut = polyOut;
    exports.easePolyInOut = polyInOut;
    exports.easeSin = sinInOut;
    exports.easeSinIn = sinIn;
    exports.easeSinOut = sinOut;
    exports.easeSinInOut = sinInOut;
    exports.easeExp = expInOut;
    exports.easeExpIn = expIn;
    exports.easeExpOut = expOut;
    exports.easeExpInOut = expInOut;
    exports.easeCircle = circleInOut;
    exports.easeCircleIn = circleIn;
    exports.easeCircleOut = circleOut;
    exports.easeCircleInOut = circleInOut;
    exports.easeBounce = bounceOut;
    exports.easeBounceIn = bounceIn;
    exports.easeBounceOut = bounceOut;
    exports.easeBounceInOut = bounceInOut;
    exports.easeBack = backInOut;
    exports.easeBackIn = backIn;
    exports.easeBackOut = backOut;
    exports.easeBackInOut = backInOut;
    exports.easeElastic = elasticOut;
    exports.easeElasticIn = elasticIn;
    exports.easeElasticOut = elasticOut;
    exports.easeElasticInOut = elasticInOut;
    exports.polygonArea = area;
    exports.polygonCentroid = centroid;
    exports.polygonHull = hull;
    exports.polygonContains = contains;
    exports.polygonLength = length$1;
    exports.path = path;
    exports.quadtree = quadtree;
    exports.queue = queue;
    exports.arc = arc;
    exports.area = area$1;
    exports.line = line;
    exports.pie = pie;
    exports.radialArea = radialArea;
    exports.radialLine = radialLine$1;
    exports.symbol = symbol;
    exports.symbols = symbols;
    exports.symbolCircle = circle;
    exports.symbolCross = cross$1;
    exports.symbolDiamond = diamond;
    exports.symbolSquare = square;
    exports.symbolStar = star;
    exports.symbolTriangle = triangle;
    exports.symbolWye = wye;
    exports.curveBasisClosed = basisClosed;
    exports.curveBasisOpen = basisOpen;
    exports.curveBasis = basis;
    exports.curveBundle = bundle;
    exports.curveCardinalClosed = cardinalClosed;
    exports.curveCardinalOpen = cardinalOpen;
    exports.curveCardinal = cardinal;
    exports.curveCatmullRomClosed = catmullRomClosed;
    exports.curveCatmullRomOpen = catmullRomOpen;
    exports.curveCatmullRom = catmullRom;
    exports.curveLinearClosed = linearClosed;
    exports.curveLinear = curveLinear;
    exports.curveMonotoneX = monotoneX;
    exports.curveMonotoneY = monotoneY;
    exports.curveNatural = natural;
    exports.curveStep = step;
    exports.curveStepAfter = stepAfter;
    exports.curveStepBefore = stepBefore;
    exports.stack = stack;
    exports.stackOffsetExpand = expand;
    exports.stackOffsetNone = none;
    exports.stackOffsetSilhouette = silhouette;
    exports.stackOffsetWiggle = wiggle;
    exports.stackOrderAscending = ascending$1;
    exports.stackOrderDescending = descending$2;
    exports.stackOrderInsideOut = insideOut;
    exports.stackOrderNone = none$1;
    exports.stackOrderReverse = reverse;
    exports.color = color;
    exports.rgb = colorRgb;
    exports.hsl = colorHsl;
    exports.lab = lab;
    exports.hcl = colorHcl;
    exports.cubehelix = cubehelix;
    exports.interpolate = interpolate;
    exports.interpolateArray = array$1;
    exports.interpolateNumber = interpolateNumber;
    exports.interpolateObject = object;
    exports.interpolateRound = interpolateRound;
    exports.interpolateString = interpolateString;
    exports.interpolateTransformCss = interpolateTransform$1;
    exports.interpolateTransformSvg = interpolateTransform$2;
    exports.interpolateZoom = interpolateZoom;
    exports.interpolateRgb = interpolateRgb;
    exports.interpolateRgbBasis = rgbBasis;
    exports.interpolateRgbBasisClosed = rgbBasisClosed;
    exports.interpolateHsl = hsl$1;
    exports.interpolateHslLong = hslLong;
    exports.interpolateLab = lab$1;
    exports.interpolateHcl = hcl$1;
    exports.interpolateHclLong = hclLong;
    exports.interpolateCubehelix = cubehelix$2;
    exports.interpolateCubehelixLong = interpolateCubehelixLong;
    exports.interpolateBasis = basis$2;
    exports.interpolateBasisClosed = basisClosed$1;
    exports.quantize = quantize;
    exports.dispatch = dispatch;
    exports.dsvFormat = dsv;
    exports.csvParse = csvParse;
    exports.csvParseRows = csvParseRows;
    exports.csvFormat = csvFormat;
    exports.csvFormatRows = csvFormatRows;
    exports.tsvParse = tsvParse;
    exports.tsvParseRows = tsvParseRows;
    exports.tsvFormat = tsvFormat;
    exports.tsvFormatRows = tsvFormatRows;
    exports.request = request;
    exports.html = html;
    exports.json = json;
    exports.text = text;
    exports.xml = xml;
    exports.csv = csv$1;
    exports.tsv = tsv$1;
    exports.now = now;
    exports.timer = timer;
    exports.timerFlush = timerFlush;
    exports.timeout = timeout$1;
    exports.interval = interval$1;
    exports.timeInterval = newInterval;
    exports.timeMillisecond = millisecond;
    exports.timeMilliseconds = milliseconds;
    exports.timeSecond = second;
    exports.timeSeconds = seconds;
    exports.timeMinute = minute;
    exports.timeMinutes = minutes;
    exports.timeHour = hour;
    exports.timeHours = hours;
    exports.timeDay = day;
    exports.timeDays = days;
    exports.timeWeek = timeWeek;
    exports.timeWeeks = sundays;
    exports.timeSunday = timeWeek;
    exports.timeSundays = sundays;
    exports.timeMonday = timeMonday;
    exports.timeMondays = mondays;
    exports.timeTuesday = tuesday;
    exports.timeTuesdays = tuesdays;
    exports.timeWednesday = wednesday;
    exports.timeWednesdays = wednesdays;
    exports.timeThursday = thursday;
    exports.timeThursdays = thursdays;
    exports.timeFriday = friday;
    exports.timeFridays = fridays;
    exports.timeSaturday = saturday;
    exports.timeSaturdays = saturdays;
    exports.timeMonth = month;
    exports.timeMonths = months;
    exports.timeYear = year;
    exports.timeYears = years;
    exports.utcMillisecond = millisecond;
    exports.utcMilliseconds = milliseconds;
    exports.utcSecond = second;
    exports.utcSeconds = seconds;
    exports.utcMinute = utcMinute;
    exports.utcMinutes = utcMinutes;
    exports.utcHour = utcHour;
    exports.utcHours = utcHours;
    exports.utcDay = utcDay;
    exports.utcDays = utcDays;
    exports.utcWeek = utcWeek;
    exports.utcWeeks = utcSundays;
    exports.utcSunday = utcWeek;
    exports.utcSundays = utcSundays;
    exports.utcMonday = utcMonday;
    exports.utcMondays = utcMondays;
    exports.utcTuesday = utcTuesday;
    exports.utcTuesdays = utcTuesdays;
    exports.utcWednesday = utcWednesday;
    exports.utcWednesdays = utcWednesdays;
    exports.utcThursday = utcThursday;
    exports.utcThursdays = utcThursdays;
    exports.utcFriday = utcFriday;
    exports.utcFridays = utcFridays;
    exports.utcSaturday = utcSaturday;
    exports.utcSaturdays = utcSaturdays;
    exports.utcMonth = utcMonth;
    exports.utcMonths = utcMonths;
    exports.utcYear = utcYear;
    exports.utcYears = utcYears;
    exports.formatLocale = formatLocale;
    exports.formatDefaultLocale = defaultLocale;
    exports.formatSpecifier = formatSpecifier;
    exports.precisionFixed = precisionFixed;
    exports.precisionPrefix = precisionPrefix;
    exports.precisionRound = precisionRound;
    exports.isoFormat = formatIso;
    exports.isoParse = parseIso;
    exports.timeFormatLocale = formatLocale$1;
    exports.timeFormatDefaultLocale = defaultLocale$1;
    exports.scaleBand = band;
    exports.scalePoint = point$4;
    exports.scaleIdentity = identity$4;
    exports.scaleLinear = linear$2;
    exports.scaleLog = log;
    exports.scaleOrdinal = ordinal;
    exports.scaleImplicit = implicit;
    exports.scalePow = pow;
    exports.scaleSqrt = sqrt;
    exports.scaleQuantile = quantile;
    exports.scaleQuantize = quantize$1;
    exports.scaleThreshold = threshold$1;
    exports.scaleTime = time;
    exports.scaleUtc = utcTime;
    exports.schemeCategory10 = category10;
    exports.schemeCategory20b = category20b;
    exports.schemeCategory20c = category20c;
    exports.schemeCategory20 = category20;
    exports.scaleSequential = sequential;
    exports.interpolateCubehelixDefault = cubehelix$3;
    exports.interpolateRainbow = rainbow$1;
    exports.interpolateWarm = warm;
    exports.interpolateCool = cool;
    exports.interpolateViridis = viridis;
    exports.interpolateMagma = magma;
    exports.interpolateInferno = inferno;
    exports.interpolatePlasma = plasma;
    exports.creator = creator;
    exports.customEvent = customEvent;
    exports.local = local;
    exports.matcher = matcher$1;
    exports.mouse = mouse;
    exports.namespace = namespace;
    exports.namespaces = namespaces;
    exports.select = select;
    exports.selectAll = selectAll;
    exports.selection = selection;
    exports.selector = selector;
    exports.selectorAll = selectorAll;
    exports.touch = touch;
    exports.touches = touches;
    exports.window = window$1;
    exports.active = active;
    exports.interrupt = interrupt;
    exports.transition = transition;
    exports.axisTop = axisTop;
    exports.axisRight = axisRight;
    exports.axisBottom = axisBottom;
    exports.axisLeft = axisLeft;
    exports.cluster = cluster;
    exports.hierarchy = hierarchy;
    exports.pack = index;
    exports.packSiblings = siblings;
    exports.packEnclose = enclose;
    exports.partition = partition;
    exports.stratify = stratify;
    exports.tree = tree;
    exports.treemap = index$1;
    exports.treemapBinary = binary;
    exports.treemapDice = treemapDice;
    exports.treemapSlice = treemapSlice;
    exports.treemapSliceDice = sliceDice;
    exports.treemapSquarify = squarify;
    exports.treemapResquarify = resquarify;
    exports.forceCenter = center$1;
    exports.forceCollide = collide;
    exports.forceLink = link;
    exports.forceManyBody = manyBody;
    exports.forceSimulation = simulation;
    exports.forceX = x$3;
    exports.forceY = y$3;
    exports.drag = drag;
    exports.dragDisable = dragDisable;
    exports.dragEnable = dragEnable;
    exports.voronoi = voronoi;
    exports.zoom = zoom;
    exports.zoomIdentity = identity$6;
    exports.zoomTransform = transform;
    exports.brush = brush;
    exports.brushX = brushX;
    exports.brushY = brushY;
    exports.brushSelection = brushSelection;
    exports.geoArea = area$2;
    exports.geoBounds = bounds;
    exports.geoCentroid = centroid$1;
    exports.geoCircle = circle$1;
    exports.geoClipExtent = extent$1;
    exports.geoDistance = distance;
    exports.geoGraticule = graticule;
    exports.geoInterpolate = interpolate$2;
    exports.geoLength = length$2;
    exports.geoPath = index$3;
    exports.geoAlbers = albers;
    exports.geoAlbersUsa = albersUsa;
    exports.geoAzimuthalEqualArea = azimuthalEqualArea;
    exports.geoAzimuthalEquidistant = azimuthalEquidistant;
    exports.geoConicConformal = conicConformal;
    exports.geoConicEqualArea = conicEqualArea;
    exports.geoConicEquidistant = conicEquidistant;
    exports.geoEquirectangular = equirectangular;
    exports.geoGnomonic = gnomonic;
    exports.geoProjection = projection;
    exports.geoProjectionMutator = projectionMutator;
    exports.geoMercator = mercator;
    exports.geoOrthographic = orthographic;
    exports.geoStereographic = stereographic;
    exports.geoTransverseMercator = transverseMercator;
    exports.geoRotation = rotation;
    exports.geoStream = geoStream;
    exports.geoTransform = transform$1;
    exports.wordwrap = wordwrap;
    exports.parseAttributes = parseAttributes;
    exports.f = f;
    exports.ascendingKey = ascendingKey;
    exports.descendingKey = descendingKey;
    exports.conventions = conventions;
    exports.attachTooltip = attachTooltip;
    exports.loadData = loadData;
    exports.nestBy = nestBy;
    exports.round = round;
  
    Object.defineProperty(exports, '__esModule', { value: true });
  
  }));