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Subscribe to eAlerts for Geom Site Updates CLICK HERE by Dan Sunday Determining the inclusion of a point P in a 2D planar polygon is a geometric problem that results in interesting algorithms. Two commonly used methods are: The Crossing Number (cn) method - which counts the number of times a ray starting from the point P crosses the polygon boundary edges. The point is outside when this "crossing number" is even; otherwise, when it is odd, the point is inside. This method is sometimes referred to as the "even-odd" test. The Winding Number (wn) method - which counts the number of times the polygon winds around the point P . The point is outside only when this "winding number" wn = 0; otherwise, the point is inside. If a polygon is simple (i.e., it has no self intersecti...

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