/// <summary>
/// Find the distance on the XY plane between two points
/// </summary>
/// <param name="ptA"></param>
/// <param name="ptB"></param>
/// <returns></returns>
public static double XYDistanceTo(this Point3f ptA, Point3f ptB)
{
return(Math.Sqrt(ptA.XYSquaredDistanceTo(ptB)));
}