Compares X, Y, M, Z, ID of this point (in that order) with that of the other point. Returns -1 if this point's value is less, 1 if greater, and 0 otherwise. Useful for sorting a group of points.
Projects this point to the point on the infinite line defined by anchor and angle (in radians). If allowOpposite is true, then the point can also snap to angle + pi radians.