text: /**
   * 坐标转换基础库
   *
   * Created by liulin on 2017/2/22.
   */
  
  
  ES.CoordTrans = {
      PI : 3.14159265358979324,
      x_pi : 3.14159265358979324 * 3000.0 / 180.0,
  
      delta : function (lat, lon) {
          // Krasovsky 1940
          //
          // a = 6378245.0, 1/f = 298.3
          // b = a * (1 - f)
          // ee = (a^2 - b^2) / a^2;
          var a = 6378245.0; //  a: 卫星椭球坐标投影到平面地图坐标系的投影因子。
          var ee = 0.00669342162296594323; //  ee: 椭球的偏心率。
          var dLat = this.transformLat(lon - 105.0, lat - 35.0);
          var dLon = this.transformLon(lon - 105.0, lat - 35.0);
          var radLat = lat / 180.0 * this.PI;
          var magic = Math.sin(radLat);
          magic = 1 - ee * magic * magic;
          var sqrtMagic = Math.sqrt(magic);
          dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * this.PI);
          dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * this.PI);
          return {'lat': dLat, 'lon': dLon};
      },
  
      //WGS-84 to GCJ-02
      gcj_encrypt : function (wgsLat, wgsLon) {
          if (this.outOfChina(wgsLat, wgsLon))
              return {'lat': wgsLat, 'lon': wgsLon};
  
          var d = this.delta(wgsLat, wgsLon);
          return {'lat' : wgsLat + d.lat,'lon' : wgsLon + d.lon};
      },
  
      //GCJ-02 to WGS-84
      gcj_decrypt : function (gcjLat, gcjLon) {
          if (this.outOfChina(gcjLat, gcjLon))
              return {'lat': gcjLat, 'lon': gcjLon};
  
          var d = this.delta(gcjLat, gcjLon);
          return {'lat': gcjLat - d.lat, 'lon': gcjLon - d.lon};
      },
  
      //GCJ-02 to WGS-84 exactly
      gcj_decrypt_exact : function (gcjLat, gcjLon) {
          var initDelta = 0.01;
          var threshold = 0.000000001;
          var dLat = initDelta, dLon = initDelta;
          var mLat = gcjLat - dLat, mLon = gcjLon - dLon;
          var pLat = gcjLat + dLat, pLon = gcjLon + dLon;
          var wgsLat, wgsLon, i = 0;
          while (1) {
              wgsLat = (mLat + pLat) / 2;
              wgsLon = (mLon + pLon) / 2;
              var tmp = this.gcj_encrypt(wgsLat, wgsLon);
              dLat = tmp.lat - gcjLat;
              dLon = tmp.lon - gcjLon;
              if ((Math.abs(dLat) < threshold) && (Math.abs(dLon) < threshold))
                  break;
  
              if (dLat > 0) pLat = wgsLat; else mLat = wgsLat;
              if (dLon > 0) pLon = wgsLon; else mLon = wgsLon;
  
              if (++i > 10000) break;
          }
          //console.log(i);
          return {'lat': wgsLat, 'lon': wgsLon};
      },
  
      //GCJ-02 to BD-09
      bd_encrypt : function (gcjLat, gcjLon) {
          var x = gcjLon, y = gcjLat;
          var z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * this.x_pi);
          var theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * this.x_pi);
          var bdLon = z * Math.cos(theta) + 0.0065;
          var bdLat = z * Math.sin(theta) + 0.006;
          return {'lat' : bdLat,'lon' : bdLon};
      },
  
      //BD-09 to GCJ-02
      bd_decrypt : function (bdLat, bdLon) {
          var x = bdLon - 0.0065, y = bdLat - 0.006;
          var z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * this.x_pi);
          var theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * this.x_pi);
          var gcjLon = z * Math.cos(theta);
          var gcjLat = z * Math.sin(theta);
          return {lat : gcjLat, lng : gcjLon};
      },
  
      //WGS-84 to Web mercator
      //mercatorLat -> y mercatorLon -> x
      mercator_encrypt : function(wgsLat, wgsLon) {
          var x = wgsLon * 20037508.34 / 180.;
          var y = Math.log(Math.tan((90. + wgsLat) * this.PI / 360.)) / (this.PI / 180.);
          y = y * 20037508.34 / 180.;
          return {'lat' : y, 'lon' : x};
          /*
           if ((Math.abs(wgsLon) > 180 || Math.abs(wgsLat) > 90))
           return null;
           var x = 6378137.0 * wgsLon * 0.017453292519943295;
           var a = wgsLat * 0.017453292519943295;
           var y = 3189068.5 * Math.log((1.0 + Math.sin(a)) / (1.0 - Math.sin(a)));
           return {'lat' : y, 'lon' : x};
           //*/
      },
  
      // Web mercator to WGS-84
      // mercatorLat -> y mercatorLon -> x
      mercator_decrypt : function(mercatorLat, mercatorLon) {
          var x = mercatorLon / 20037508.34 * 180.;
          var y = mercatorLat / 20037508.34 * 180.;
          y = 180 / this.PI * (2 * Math.atan(Math.exp(y * this.PI / 180.)) - this.PI / 2);
          return {'lat' : y, 'lon' : x};
          /*
           if (Math.abs(mercatorLon) < 180 && Math.abs(mercatorLat) < 90)
           return null;
           if ((Math.abs(mercatorLon) > 20037508.3427892) || (Math.abs(mercatorLat) > 20037508.3427892))
           return null;
           var a = mercatorLon / 6378137.0 * 57.295779513082323;
           var x = a - (Math.floor(((a + 180.0) / 360.0)) * 360.0);
           var y = (1.5707963267948966 - (2.0 * Math.atan(Math.exp((-1.0 * mercatorLat) / 6378137.0)))) * 57.295779513082323;
           return {'lat' : y, 'lon' : x};
           //*/
      },
  
      // two point's distance
      distance : function (latA, lonA, latB, lonB) {
          var earthR = 6371000.;
          var x = Math.cos(latA * this.PI / 180.) * Math.cos(latB * this.PI / 180.) * Math.cos((lonA - lonB) * this.PI / 180);
          var y = Math.sin(latA * this.PI / 180.) * Math.sin(latB * this.PI / 180.);
          var s = x + y;
          if (s > 1) s = 1;
          if (s < -1) s = -1;
          var alpha = Math.acos(s);
          var distance1 = alpha * earthR;
          return distance1;
      },
  
      outOfChina : function (lat, lon) {
          if (lon < 72.004 || lon > 137.8347)
              return true;
          if (lat < 0.8293 || lat > 55.8271)
              return true;
          return false;
      },
  
      transformLat : function (x, y) {
          var ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
          ret += (20.0 * Math.sin(6.0 * x * this.PI) + 20.0 * Math.sin(2.0 * x * this.PI)) * 2.0 / 3.0;
          ret += (20.0 * Math.sin(y * this.PI) + 40.0 * Math.sin(y / 3.0 * this.PI)) * 2.0 / 3.0;
          ret += (160.0 * Math.sin(y / 12.0 * this.PI) + 320 * Math.sin(y * this.PI / 30.0)) * 2.0 / 3.0;
          return ret;
      },
  
      transformLon : function (x, y) {
          var ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
          ret += (20.0 * Math.sin(6.0 * x * this.PI) + 20.0 * Math.sin(2.0 * x * this.PI)) * 2.0 / 3.0;
          ret += (20.0 * Math.sin(x * this.PI) + 40.0 * Math.sin(x / 3.0 * this.PI)) * 2.0 / 3.0;
          ret += (150.0 * Math.sin(x / 12.0 * this.PI) + 300.0 * Math.sin(x / 30.0 * this.PI)) * 2.0 / 3.0;
          return ret;
      }
  
  };
  
  