public Polygon TwoPieces(Polygon polygon1, Polygon polygon2, LineString line1, LineString line2)
{
if (polygon1.Intersects(polygon2) || polygon1.Touches(polygon2))
{
return polygon1.Union(polygon2) as Polygon;
}
else
{
var pg = GetConvexHull(line1, line2);
return pg.Union(polygon1).Union(polygon2) as Polygon;
}
}
