Find any point that is beyond the right most point of the polygon. That's easy, just find a x that is greater than the greatest x of the polygon, with any reasonable y. Call this point ForSureOutside.

Then draw a line between the point under investigation and ForSureOutside. (Not physically draw, but find the equation of the line with those two points)

If this line intersects with any line SEGMENT that form the polygon, then the point under investigation is inside the polygon.

In reply to Re: Determing whether point falls inside or outside a complex polygon by pg
in thread Determing whether point falls inside or outside a complex polygon by Anonymous Monk

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