/// <summary>
/// Returns a rectangle representing the given ring - if it is an axis-parallel rectangle. Otherwise returns null;
/// </summary>
/// <param name="name"></param>
/// <returns></returns>
public RectangleF?GetRingAsRectF(string name)
{
var poly = this[name];
var rect = PolygonMath.GetBoundingBox(poly);
var poly2 = PolygonMath.ToPoly(rect);
return(PolygonMath.ArraysEqual(poly, poly2) ? (RectangleF?)rect : null);
}