public static PointLatLngAlt Subtract(PointLatLngAlt pt, SizeLatLngAlt sz)
 {
     return(new PointLatLngAlt(pt.Lat + sz.HeightLat, pt.Lng - sz.WidthLng, pt.Alt - sz.Alt));
 }
 public SizeLatLngAlt(PointLatLngAlt pt)
 {
     this.heightLat = pt.Lat;
     this.widthLng  = pt.Lng;
     this.alt       = pt.Alt;
 }
 public static PointLatLngAlt Add(PointLatLngAlt pt, SizeLatLngAlt sz)
 {
     return(new PointLatLngAlt(pt.Lat - sz.HeightLat, pt.Lng + sz.WidthLng, pt.Alt + sz.Alt));
 }
 public void Offset(PointLatLngAlt pos)
 {
     this.Offset(pos.Lat, pos.Lng, pos.Alt);
 }