/// <summary>
///The inverse of ToCartesian(). Always returns a FixedLatLng.
/// </summary>
public static LatLng FromCartesian(CartesianPoint pt)
{
int lat = pt.Y - 90 * FixedLatLng.ScaleFactorInt;
int lng = pt.X - 180 * FixedLatLng.ScaleFactorInt;
return new FixedLatLng(lat, lng);
}