private void TestAlogrithms()
{
GPSPoint p1 = new GPSPoint(117.282203, 31.86491, 0);
GPSPoint p2 = new GPSPoint(117.281501, 31.86434, 0);
//答案是91.65m
double distance1 = p1.DistanceToOtherPointOnEarth(p2);
double[] xy1 = p1.ProjectedPoint;
double[] xy2 = p2.ProjectedPoint;
double distance2 = Math.Sqrt((xy1[0] - xy2[0]) * (xy1[0] - xy2[0]) + (xy1[1] - xy2[1]) * (xy1[1] - xy2[1]));
MessageBox.Show(distance1 + "----" + distance2);
}