text: (function (global, factory) {
  	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
  	typeof define === 'function' && define.amd ? define(['exports'], factory) :
  	(factory((global.mgrs = global.mgrs || {})));
  }(this, (function (exports) { 'use strict';
  
  /**
   * UTM zones are grouped, and assigned to one of a group of 6
   * sets.
   *
   * {int} @private
   */
  var NUM_100K_SETS = 6;
  
  /**
   * The column letters (for easting) of the lower left value, per
   * set.
   *
   * {string} @private
   */
  var SET_ORIGIN_COLUMN_LETTERS = 'AJSAJS';
  
  /**
   * The row letters (for northing) of the lower left value, per
   * set.
   *
   * {string} @private
   */
  var SET_ORIGIN_ROW_LETTERS = 'AFAFAF';
  
  var A = 65; // A
  var I = 73; // I
  var O = 79; // O
  var V = 86; // V
  var Z = 90; // Z
  var mgrs = {
    forward: forward,
    inverse: inverse,
    toPoint: toPoint
  };
  /**
   * Conversion of lat/lon to MGRS.
   *
   * @param {object} ll Object literal with lat and lon properties on a
   *     WGS84 ellipsoid.
   * @param {int} accuracy Accuracy in digits (5 for 1 m, 4 for 10 m, 3 for
   *      100 m, 2 for 1000 m or 1 for 10000 m). Optional, default is 5.
   * @return {string} the MGRS string for the given location and accuracy.
   */
  function forward(ll, accuracy) {
    accuracy = accuracy || 5; // default accuracy 1m
    return encode(LLtoUTM({
      lat: ll[1],
      lon: ll[0]
    }), accuracy);
  }
  
  /**
   * Conversion of MGRS to lat/lon.
   *
   * @param {string} mgrs MGRS string.
   * @return {array} An array with left (longitude), bottom (latitude), right
   *     (longitude) and top (latitude) values in WGS84, representing the
   *     bounding box for the provided MGRS reference.
   */
  function inverse(mgrs) {
    var bbox = UTMtoLL(decode(mgrs.toUpperCase()));
    if (bbox.lat && bbox.lon) {
      return [bbox.lon, bbox.lat, bbox.lon, bbox.lat];
    }
    return [bbox.left, bbox.bottom, bbox.right, bbox.top];
  }
  
  function toPoint(mgrs) {
    var bbox = UTMtoLL(decode(mgrs.toUpperCase()));
    if (bbox.lat && bbox.lon) {
      return [bbox.lon, bbox.lat];
    }
    return [(bbox.left + bbox.right) / 2, (bbox.top + bbox.bottom) / 2];
  }
  /**
   * Conversion from degrees to radians.
   *
   * @private
   * @param {number} deg the angle in degrees.
   * @return {number} the angle in radians.
   */
  function degToRad(deg) {
    return (deg * (Math.PI / 180.0));
  }
  
  /**
   * Conversion from radians to degrees.
   *
   * @private
   * @param {number} rad the angle in radians.
   * @return {number} the angle in degrees.
   */
  function radToDeg(rad) {
    return (180.0 * (rad / Math.PI));
  }
  
  /**
   * Converts a set of Longitude and Latitude co-ordinates to UTM
   * using the WGS84 ellipsoid.
   *
   * @private
   * @param {object} ll Object literal with lat and lon properties
   *     representing the WGS84 coordinate to be converted.
   * @return {object} Object literal containing the UTM value with easting,
   *     northing, zoneNumber and zoneLetter properties, and an optional
   *     accuracy property in digits. Returns null if the conversion failed.
   */
  function LLtoUTM(ll) {
    var Lat = ll.lat;
    var Long = ll.lon;
    var a = 6378137.0; //ellip.radius;
    var eccSquared = 0.00669438; //ellip.eccsq;
    var k0 = 0.9996;
    var LongOrigin;
    var eccPrimeSquared;
    var N, T, C, A, M;
    var LatRad = degToRad(Lat);
    var LongRad = degToRad(Long);
    var LongOriginRad;
    var ZoneNumber;
    // (int)
    ZoneNumber = Math.floor((Long + 180) / 6) + 1;
  
    //Make sure the longitude 180.00 is in Zone 60
    if (Long === 180) {
      ZoneNumber = 60;
    }
  
    // Special zone for Norway
    if (Lat >= 56.0 && Lat < 64.0 && Long >= 3.0 && Long < 12.0) {
      ZoneNumber = 32;
    }
  
    // Special zones for Svalbard
    if (Lat >= 72.0 && Lat < 84.0) {
      if (Long >= 0.0 && Long < 9.0) {
        ZoneNumber = 31;
      }
      else if (Long >= 9.0 && Long < 21.0) {
        ZoneNumber = 33;
      }
      else if (Long >= 21.0 && Long < 33.0) {
        ZoneNumber = 35;
      }
      else if (Long >= 33.0 && Long < 42.0) {
        ZoneNumber = 37;
      }
    }
  
    LongOrigin = (ZoneNumber - 1) * 6 - 180 + 3; //+3 puts origin
    // in middle of
    // zone
    LongOriginRad = degToRad(LongOrigin);
  
    eccPrimeSquared = (eccSquared) / (1 - eccSquared);
  
    N = a / Math.sqrt(1 - eccSquared * Math.sin(LatRad) * Math.sin(LatRad));
    T = Math.tan(LatRad) * Math.tan(LatRad);
    C = eccPrimeSquared * Math.cos(LatRad) * Math.cos(LatRad);
    A = Math.cos(LatRad) * (LongRad - LongOriginRad);
  
    M = a * ((1 - eccSquared / 4 - 3 * eccSquared * eccSquared / 64 - 5 * eccSquared * eccSquared * eccSquared / 256) * LatRad - (3 * eccSquared / 8 + 3 * eccSquared * eccSquared / 32 + 45 * eccSquared * eccSquared * eccSquared / 1024) * Math.sin(2 * LatRad) + (15 * eccSquared * eccSquared / 256 + 45 * eccSquared * eccSquared * eccSquared / 1024) * Math.sin(4 * LatRad) - (35 * eccSquared * eccSquared * eccSquared / 3072) * Math.sin(6 * LatRad));
  
    var UTMEasting = (k0 * N * (A + (1 - T + C) * A * A * A / 6.0 + (5 - 18 * T + T * T + 72 * C - 58 * eccPrimeSquared) * A * A * A * A * A / 120.0) + 500000.0);
  
    var UTMNorthing = (k0 * (M + N * Math.tan(LatRad) * (A * A / 2 + (5 - T + 9 * C + 4 * C * C) * A * A * A * A / 24.0 + (61 - 58 * T + T * T + 600 * C - 330 * eccPrimeSquared) * A * A * A * A * A * A / 720.0)));
    if (Lat < 0.0) {
      UTMNorthing += 10000000.0; //10000000 meter offset for
      // southern hemisphere
    }
  
    return {
      northing: Math.trunc(UTMNorthing),
      easting: Math.trunc(UTMEasting),
      zoneNumber: ZoneNumber,
      zoneLetter: getLetterDesignator(Lat)
    };
  }
  
  /**
   * Converts UTM coords to lat/long, using the WGS84 ellipsoid. This is a convenience
   * class where the Zone can be specified as a single string eg."60N" which
   * is then broken down into the ZoneNumber and ZoneLetter.
   *
   * @private
   * @param {object} utm An object literal with northing, easting, zoneNumber
   *     and zoneLetter properties. If an optional accuracy property is
   *     provided (in meters), a bounding box will be returned instead of
   *     latitude and longitude.
   * @return {object} An object literal containing either lat and lon values
   *     (if no accuracy was provided), or top, right, bottom and left values
   *     for the bounding box calculated according to the provided accuracy.
   *     Returns null if the conversion failed.
   */
  function UTMtoLL(utm) {
  
    var UTMNorthing = utm.northing;
    var UTMEasting = utm.easting;
    var zoneLetter = utm.zoneLetter;
    var zoneNumber = utm.zoneNumber;
    // check the ZoneNummber is valid
    if (zoneNumber < 0 || zoneNumber > 60) {
      return null;
    }
  
    var k0 = 0.9996;
    var a = 6378137.0; //ellip.radius;
    var eccSquared = 0.00669438; //ellip.eccsq;
    var eccPrimeSquared;
    var e1 = (1 - Math.sqrt(1 - eccSquared)) / (1 + Math.sqrt(1 - eccSquared));
    var N1, T1, C1, R1, D, M;
    var LongOrigin;
    var mu, phi1Rad;
  
    // remove 500,000 meter offset for longitude
    var x = UTMEasting - 500000.0;
    var y = UTMNorthing;
  
    // We must know somehow if we are in the Northern or Southern
    // hemisphere, this is the only time we use the letter So even
    // if the Zone letter isn't exactly correct it should indicate
    // the hemisphere correctly
    if (zoneLetter < 'N') {
      y -= 10000000.0; // remove 10,000,000 meter offset used
      // for southern hemisphere
    }
  
    // There are 60 zones with zone 1 being at West -180 to -174
    LongOrigin = (zoneNumber - 1) * 6 - 180 + 3; // +3 puts origin
    // in middle of
    // zone
  
    eccPrimeSquared = (eccSquared) / (1 - eccSquared);
  
    M = y / k0;
    mu = M / (a * (1 - eccSquared / 4 - 3 * eccSquared * eccSquared / 64 - 5 * eccSquared * eccSquared * eccSquared / 256));
  
    phi1Rad = mu + (3 * e1 / 2 - 27 * e1 * e1 * e1 / 32) * Math.sin(2 * mu) + (21 * e1 * e1 / 16 - 55 * e1 * e1 * e1 * e1 / 32) * Math.sin(4 * mu) + (151 * e1 * e1 * e1 / 96) * Math.sin(6 * mu);
    // double phi1 = ProjMath.radToDeg(phi1Rad);
  
    N1 = a / Math.sqrt(1 - eccSquared * Math.sin(phi1Rad) * Math.sin(phi1Rad));
    T1 = Math.tan(phi1Rad) * Math.tan(phi1Rad);
    C1 = eccPrimeSquared * Math.cos(phi1Rad) * Math.cos(phi1Rad);
    R1 = a * (1 - eccSquared) / Math.pow(1 - eccSquared * Math.sin(phi1Rad) * Math.sin(phi1Rad), 1.5);
    D = x / (N1 * k0);
  
    var lat = phi1Rad - (N1 * Math.tan(phi1Rad) / R1) * (D * D / 2 - (5 + 3 * T1 + 10 * C1 - 4 * C1 * C1 - 9 * eccPrimeSquared) * D * D * D * D / 24 + (61 + 90 * T1 + 298 * C1 + 45 * T1 * T1 - 252 * eccPrimeSquared - 3 * C1 * C1) * D * D * D * D * D * D / 720);
    lat = radToDeg(lat);
  
    var lon = (D - (1 + 2 * T1 + C1) * D * D * D / 6 + (5 - 2 * C1 + 28 * T1 - 3 * C1 * C1 + 8 * eccPrimeSquared + 24 * T1 * T1) * D * D * D * D * D / 120) / Math.cos(phi1Rad);
    lon = LongOrigin + radToDeg(lon);
  
    var result;
    if (utm.accuracy) {
      var topRight = UTMtoLL({
        northing: utm.northing + utm.accuracy,
        easting: utm.easting + utm.accuracy,
        zoneLetter: utm.zoneLetter,
        zoneNumber: utm.zoneNumber
      });
      result = {
        top: topRight.lat,
        right: topRight.lon,
        bottom: lat,
        left: lon
      };
    }
    else {
      result = {
        lat: lat,
        lon: lon
      };
    }
    return result;
  }
  
  /**
   * Calculates the MGRS letter designator for the given latitude.
   *
   * @private
   * @param {number} lat The latitude in WGS84 to get the letter designator
   *     for.
   * @return {char} The letter designator.
   */
  function getLetterDesignator(lat) {
    //This is here as an error flag to show that the Latitude is
    //outside MGRS limits
    var LetterDesignator = 'Z';
  
    if ((84 >= lat) && (lat >= 72)) {
      LetterDesignator = 'X';
    }
    else if ((72 > lat) && (lat >= 64)) {
      LetterDesignator = 'W';
    }
    else if ((64 > lat) && (lat >= 56)) {
      LetterDesignator = 'V';
    }
    else if ((56 > lat) && (lat >= 48)) {
      LetterDesignator = 'U';
    }
    else if ((48 > lat) && (lat >= 40)) {
      LetterDesignator = 'T';
    }
    else if ((40 > lat) && (lat >= 32)) {
      LetterDesignator = 'S';
    }
    else if ((32 > lat) && (lat >= 24)) {
      LetterDesignator = 'R';
    }
    else if ((24 > lat) && (lat >= 16)) {
      LetterDesignator = 'Q';
    }
    else if ((16 > lat) && (lat >= 8)) {
      LetterDesignator = 'P';
    }
    else if ((8 > lat) && (lat >= 0)) {
      LetterDesignator = 'N';
    }
    else if ((0 > lat) && (lat >= -8)) {
      LetterDesignator = 'M';
    }
    else if ((-8 > lat) && (lat >= -16)) {
      LetterDesignator = 'L';
    }
    else if ((-16 > lat) && (lat >= -24)) {
      LetterDesignator = 'K';
    }
    else if ((-24 > lat) && (lat >= -32)) {
      LetterDesignator = 'J';
    }
    else if ((-32 > lat) && (lat >= -40)) {
      LetterDesignator = 'H';
    }
    else if ((-40 > lat) && (lat >= -48)) {
      LetterDesignator = 'G';
    }
    else if ((-48 > lat) && (lat >= -56)) {
      LetterDesignator = 'F';
    }
    else if ((-56 > lat) && (lat >= -64)) {
      LetterDesignator = 'E';
    }
    else if ((-64 > lat) && (lat >= -72)) {
      LetterDesignator = 'D';
    }
    else if ((-72 > lat) && (lat >= -80)) {
      LetterDesignator = 'C';
    }
    return LetterDesignator;
  }
  
  /**
   * Encodes a UTM location as MGRS string.
   *
   * @private
   * @param {object} utm An object literal with easting, northing,
   *     zoneLetter, zoneNumber
   * @param {number} accuracy Accuracy in digits (1-5).
   * @return {string} MGRS string for the given UTM location.
   */
  function encode(utm, accuracy) {
    // prepend with leading zeroes
    var seasting = "00000" + utm.easting,
      snorthing = "00000" + utm.northing;
  
    return utm.zoneNumber + utm.zoneLetter + get100kID(utm.easting, utm.northing, utm.zoneNumber) + seasting.substr(seasting.length - 5, accuracy) + snorthing.substr(snorthing.length - 5, accuracy);
  }
  
  /**
   * Get the two letter 100k designator for a given UTM easting,
   * northing and zone number value.
   *
   * @private
   * @param {number} easting
   * @param {number} northing
   * @param {number} zoneNumber
   * @return {string} the two letter 100k designator for the given UTM location.
   */
  function get100kID(easting, northing, zoneNumber) {
    var setParm = get100kSetForZone(zoneNumber);
    var setColumn = Math.floor(easting / 100000);
    var setRow = Math.floor(northing / 100000) % 20;
    return getLetter100kID(setColumn, setRow, setParm);
  }
  
  /**
   * Given a UTM zone number, figure out the MGRS 100K set it is in.
   *
   * @private
   * @param {number} i An UTM zone number.
   * @return {number} the 100k set the UTM zone is in.
   */
  function get100kSetForZone(i) {
    var setParm = i % NUM_100K_SETS;
    if (setParm === 0) {
      setParm = NUM_100K_SETS;
    }
  
    return setParm;
  }
  
  /**
   * Get the two-letter MGRS 100k designator given information
   * translated from the UTM northing, easting and zone number.
   *
   * @private
   * @param {number} column the column index as it relates to the MGRS
   *        100k set spreadsheet, created from the UTM easting.
   *        Values are 1-8.
   * @param {number} row the row index as it relates to the MGRS 100k set
   *        spreadsheet, created from the UTM northing value. Values
   *        are from 0-19.
   * @param {number} parm the set block, as it relates to the MGRS 100k set
   *        spreadsheet, created from the UTM zone. Values are from
   *        1-60.
   * @return {string} two letter MGRS 100k code.
   */
  function getLetter100kID(column, row, parm) {
    // colOrigin and rowOrigin are the letters at the origin of the set
    var index = parm - 1;
    var colOrigin = SET_ORIGIN_COLUMN_LETTERS.charCodeAt(index);
    var rowOrigin = SET_ORIGIN_ROW_LETTERS.charCodeAt(index);
  
    // colInt and rowInt are the letters to build to return
    var colInt = colOrigin + column - 1;
    var rowInt = rowOrigin + row;
    var rollover = false;
  
    if (colInt > Z) {
      colInt = colInt - Z + A - 1;
      rollover = true;
    }
  
    if (colInt === I || (colOrigin < I && colInt > I) || ((colInt > I || colOrigin < I) && rollover)) {
      colInt++;
    }
  
    if (colInt === O || (colOrigin < O && colInt > O) || ((colInt > O || colOrigin < O) && rollover)) {
      colInt++;
  
      if (colInt === I) {
        colInt++;
      }
    }
  
    if (colInt > Z) {
      colInt = colInt - Z + A - 1;
    }
  
    if (rowInt > V) {
      rowInt = rowInt - V + A - 1;
      rollover = true;
    }
    else {
      rollover = false;
    }
  
    if (((rowInt === I) || ((rowOrigin < I) && (rowInt > I))) || (((rowInt > I) || (rowOrigin < I)) && rollover)) {
      rowInt++;
    }
  
    if (((rowInt === O) || ((rowOrigin < O) && (rowInt > O))) || (((rowInt > O) || (rowOrigin < O)) && rollover)) {
      rowInt++;
  
      if (rowInt === I) {
        rowInt++;
      }
    }
  
    if (rowInt > V) {
      rowInt = rowInt - V + A - 1;
    }
  
    var twoLetter = String.fromCharCode(colInt) + String.fromCharCode(rowInt);
    return twoLetter;
  }
  
  /**
   * Decode the UTM parameters from a MGRS string.
   *
   * @private
   * @param {string} mgrsString an UPPERCASE coordinate string is expected.
   * @return {object} An object literal with easting, northing, zoneLetter,
   *     zoneNumber and accuracy (in meters) properties.
   */
  function decode(mgrsString) {
  
    if (mgrsString && mgrsString.length === 0) {
      throw ("MGRSPoint coverting from nothing");
    }
  
    var length = mgrsString.length;
  
    var hunK = null;
    var sb = "";
    var testChar;
    var i = 0;
  
    // get Zone number
    while (!(/[A-Z]/).test(testChar = mgrsString.charAt(i))) {
      if (i >= 2) {
        throw ("MGRSPoint bad conversion from: " + mgrsString);
      }
      sb += testChar;
      i++;
    }
  
    var zoneNumber = parseInt(sb, 10);
  
    if (i === 0 || i + 3 > length) {
      // A good MGRS string has to be 4-5 digits long,
      // ##AAA/#AAA at least.
      throw ("MGRSPoint bad conversion from: " + mgrsString);
    }
  
    var zoneLetter = mgrsString.charAt(i++);
  
    // Should we check the zone letter here? Why not.
    if (zoneLetter <= 'A' || zoneLetter === 'B' || zoneLetter === 'Y' || zoneLetter >= 'Z' || zoneLetter === 'I' || zoneLetter === 'O') {
      throw ("MGRSPoint zone letter " + zoneLetter + " not handled: " + mgrsString);
    }
  
    hunK = mgrsString.substring(i, i += 2);
  
    var set = get100kSetForZone(zoneNumber);
  
    var east100k = getEastingFromChar(hunK.charAt(0), set);
    var north100k = getNorthingFromChar(hunK.charAt(1), set);
  
    // We have a bug where the northing may be 2000000 too low.
    // How
    // do we know when to roll over?
  
    while (north100k < getMinNorthing(zoneLetter)) {
      north100k += 2000000;
    }
  
    // calculate the char index for easting/northing separator
    var remainder = length - i;
  
    if (remainder % 2 !== 0) {
      throw ("MGRSPoint has to have an even number \nof digits after the zone letter and two 100km letters - front \nhalf for easting meters, second half for \nnorthing meters" + mgrsString);
    }
  
    var sep = remainder / 2;
  
    var sepEasting = 0.0;
    var sepNorthing = 0.0;
    var accuracyBonus, sepEastingString, sepNorthingString, easting, northing;
    if (sep > 0) {
      accuracyBonus = 100000.0 / Math.pow(10, sep);
      sepEastingString = mgrsString.substring(i, i + sep);
      sepEasting = parseFloat(sepEastingString) * accuracyBonus;
      sepNorthingString = mgrsString.substring(i + sep);
      sepNorthing = parseFloat(sepNorthingString) * accuracyBonus;
    }
  
    easting = sepEasting + east100k;
    northing = sepNorthing + north100k;
  
    return {
      easting: easting,
      northing: northing,
      zoneLetter: zoneLetter,
      zoneNumber: zoneNumber,
      accuracy: accuracyBonus
    };
  }
  
  /**
   * Given the first letter from a two-letter MGRS 100k zone, and given the
   * MGRS table set for the zone number, figure out the easting value that
   * should be added to the other, secondary easting value.
   *
   * @private
   * @param {char} e The first letter from a two-letter MGRS 100´k zone.
   * @param {number} set The MGRS table set for the zone number.
   * @return {number} The easting value for the given letter and set.
   */
  function getEastingFromChar(e, set) {
    // colOrigin is the letter at the origin of the set for the
    // column
    var curCol = SET_ORIGIN_COLUMN_LETTERS.charCodeAt(set - 1);
    var eastingValue = 100000.0;
    var rewindMarker = false;
  
    while (curCol !== e.charCodeAt(0)) {
      curCol++;
      if (curCol === I) {
        curCol++;
      }
      if (curCol === O) {
        curCol++;
      }
      if (curCol > Z) {
        if (rewindMarker) {
          throw ("Bad character: " + e);
        }
        curCol = A;
        rewindMarker = true;
      }
      eastingValue += 100000.0;
    }
  
    return eastingValue;
  }
  
  /**
   * Given the second letter from a two-letter MGRS 100k zone, and given the
   * MGRS table set for the zone number, figure out the northing value that
   * should be added to the other, secondary northing value. You have to
   * remember that Northings are determined from the equator, and the vertical
   * cycle of letters mean a 2000000 additional northing meters. This happens
   * approx. every 18 degrees of latitude. This method does *NOT* count any
   * additional northings. You have to figure out how many 2000000 meters need
   * to be added for the zone letter of the MGRS coordinate.
   *
   * @private
   * @param {char} n Second letter of the MGRS 100k zone
   * @param {number} set The MGRS table set number, which is dependent on the
   *     UTM zone number.
   * @return {number} The northing value for the given letter and set.
   */
  function getNorthingFromChar(n, set) {
  
    if (n > 'V') {
      throw ("MGRSPoint given invalid Northing " + n);
    }
  
    // rowOrigin is the letter at the origin of the set for the
    // column
    var curRow = SET_ORIGIN_ROW_LETTERS.charCodeAt(set - 1);
    var northingValue = 0.0;
    var rewindMarker = false;
  
    while (curRow !== n.charCodeAt(0)) {
      curRow++;
      if (curRow === I) {
        curRow++;
      }
      if (curRow === O) {
        curRow++;
      }
      // fixing a bug making whole application hang in this loop
      // when 'n' is a wrong character
      if (curRow > V) {
        if (rewindMarker) { // making sure that this loop ends
          throw ("Bad character: " + n);
        }
        curRow = A;
        rewindMarker = true;
      }
      northingValue += 100000.0;
    }
  
    return northingValue;
  }
  
  /**
   * The function getMinNorthing returns the minimum northing value of a MGRS
   * zone.
   *
   * Ported from Geotrans' c Lattitude_Band_Value structure table.
   *
   * @private
   * @param {char} zoneLetter The MGRS zone to get the min northing for.
   * @return {number}
   */
  function getMinNorthing(zoneLetter) {
    var northing;
    switch (zoneLetter) {
    case 'C':
      northing = 1100000.0;
      break;
    case 'D':
      northing = 2000000.0;
      break;
    case 'E':
      northing = 2800000.0;
      break;
    case 'F':
      northing = 3700000.0;
      break;
    case 'G':
      northing = 4600000.0;
      break;
    case 'H':
      northing = 5500000.0;
      break;
    case 'J':
      northing = 6400000.0;
      break;
    case 'K':
      northing = 7300000.0;
      break;
    case 'L':
      northing = 8200000.0;
      break;
    case 'M':
      northing = 9100000.0;
      break;
    case 'N':
      northing = 0.0;
      break;
    case 'P':
      northing = 800000.0;
      break;
    case 'Q':
      northing = 1700000.0;
      break;
    case 'R':
      northing = 2600000.0;
      break;
    case 'S':
      northing = 3500000.0;
      break;
    case 'T':
      northing = 4400000.0;
      break;
    case 'U':
      northing = 5300000.0;
      break;
    case 'V':
      northing = 6200000.0;
      break;
    case 'W':
      northing = 7000000.0;
      break;
    case 'X':
      northing = 7900000.0;
      break;
    default:
      northing = -1.0;
    }
    if (northing >= 0.0) {
      return northing;
    }
    else {
      throw ("Invalid zone letter: " + zoneLetter);
    }
  
  }
  
  exports['default'] = mgrs;
  exports.forward = forward;
  exports.inverse = inverse;
  exports.toPoint = toPoint;
  
  Object.defineProperty(exports, '__esModule', { value: true });
  
  })));