Returns that latitude and longitude that this point represents
    under a spherical Earth model.

def ToLatLng(self):
    """
    Returns that latitude and longitude that this point represents
    under a spherical Earth model.
    """
    rad_lat = math.atan2(self.z, math.sqrt(self.x * self.x + self.y * self.y))
    rad_lng = math.atan2(self.y, self.x)
    return (rad_lat * 180.0 / math.pi, rad_lng * 180.0 / math.pi)