Given a large set of vertices in a non-convex polygon, how can i find the edges?

Posted by tommy chheng on Stack Overflow See other posts from Stack Overflow or by tommy chheng
Published on 2010-04-30T00:19:35Z Indexed on 2010/04/30 0:27 UTC
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polygons

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concave

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outline

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vertices

I have a set of vertices(called A) and I want to find all the border vertices such that this border vertices set is an outline of the shape.

Many of the vertices in A are redundant because they are inside the shape, I want to get rid of these vertices.

My question is similar to http://stackoverflow.com/questions/477867/best-algorithm-to-find-the-edges-polygon-of-vertices but i need it to work for a non-convex polygon case.

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