private string CreateSvgPoint(DblPoint2 p1, double r)
 {
     return string.Format(GetCI(), "  <circle cx=\"{0}\" cy=\"{1}\" r=\"{2}\"/>\r\n", p1.x, p1.y, r);
 }
 private string CreateSvgPoint(DblPoint2 p1)
 {
     return CreateSvgPoint(p1, 5);
 }