Returns the coordinates from position in meters

def unproject(self, xy):
        """
        Returns the coordinates from position in meters
        """
        (x, y) = xy
        lng = x/EARTH_RADIUS * RAD_TO_DEG
        lat = 2 * atan(exp(y/EARTH_RADIUS)) - pi/2 * RAD_TO_DEG
        return (lng, lat)