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Re: Polygon Smoothing [message #70832 is a reply to message #70831]

Mon, 10 May 2010 13:03

Kenneth P. Bowman
Messages: 585
Registered: May 2000

Senior Member

In article <MPG.2651f81de68373869896d4@news.giganews.com>,
David Fanning <news@dfanning.com> wrote:

> Folks,
>
> I have a shape file describing a 2D polygon that is *extremely*
> complex and detailed. For my puposes, overly so. I would like
> to "simplify" or "smooth" this polygon to make it more suitable
> for my purpose (using it as a cookie-cutter for extracting data).
> Has anyone written a polygon smoothing routine, possibly using
> B�zier curves, in IDL to do such a thing? Would you be willing
> to share it?
>
> Thanks,
>
> David

One simple algorithm is to traverse the polygon and remove
points that are nearly collinear. For any three sequential
points you can get the angle at the middle point from the
dot product. If the curvature is less than some threshold,
remove the middle point. You probably want to check the
distance between the points as well as the curvature.

Apply repeatedly until satisfied.

Ken

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[Message index]

		Re: Polygon Smoothing By: KRDean on Tue, 11 May 2010 06:52
		Re: Polygon Smoothing By: Karl[1] on Mon, 10 May 2010 15:46
		Re: Polygon Smoothing By: Kenneth P. Bowman on Mon, 10 May 2010 13:03

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