private float PointToSegmentClosestPoint(geoPoint P, geoPoint V0, ref geoPoint V1, ref geoPoint projection)
{
// Input: P = a 3D point
// PL = a plane with point V0 and normal n
// Output: ClosestPt = base point on segment of perpendicular from P
// Return: the minimum distance from P to the segment
float length = 0;
float t = 0;
length = (V1.subtract(V0)).DotProduct(V1.subtract(V0));
if (length == 0)
{
projection = V1;
}
else
{
t = Math.Max(0, Math.Min(1, (P.subtract(V0)).DotProduct(V1.subtract(V0)) / length));
projection = V0.Addition((V1.subtract(V0)).Multiply(t));
}
return(projection.distance(ref P));
}
private float PintToPlaneClosestPoint(geoPoint Q, geoPoint V0, ref geoPoint V1, geoPoint V2, ref geoPoint projection)
{
// Input: P = a 3D point
// PL = a plane with point V0 and normal n
// Output: ClosestPt = base point on PL of perpendicular from P
float sb = 0;
float sn = 0;
float sd = 0;
geoPoint a = null;
geoPoint b = null;
geoPoint n = null;
a = V0.subtract(V1);
b = V0.subtract(V2);
n = a.CrossProduct(b);
sn = -n.DotProduct(Q.subtract(V0));
sd = n.DotProduct(n);
sb = sn / sd;
projection = Q.Addition(n.Multiply(sb));
return(projection.distance(ref Q));
}