code: public double distanceFrom(LatLong end) {
  
          double dLat = (end.getLatitude() - getLatitude()) * Math.PI / 180;
          double dLon = (end.getLongitude() - getLongitude()) * Math.PI / 180;
  
          double a = Math.sin(dLat / 2) * Math.sin(dLat / 2)
                  + Math.cos(getLatitude() * Math.PI / 180)
                  * Math.cos(end.getLatitude() * Math.PI / 180)
                  * Math.sin(dLon / 2) * Math.sin(dLon / 2);
  
          double c = 2.0 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
          double d = EarthRadiusMeters * c;
          return d;
      }
docs: From v3_epoly.js, calculates the distance between this LatLong point and
  another.
  
  @param end The end point to calculate the distance to.
  @return The distance, in metres, to the end point.