code: public double getAngle(Location location) {
          // Euclidean distance (Pythagorean theorem) - not correct when the surface is a sphere
          double latitudeDifference = location.latitude - latitude;
          double longitudeDifference = location.longitude - longitude;
          return Math.atan2(latitudeDifference, longitudeDifference);
      }
docs: The angle relative to the direction EAST.
  @param location never null
  @return in Cartesian coordinates