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Re: point inside polygon [message #11506 is a reply to message #11494]

Wed, 01 April 1998 00:00

wmc
Messages: 117
Registered: February 1995

Senior Member

In article C0684CDB@oma.be, Philippe Peeters <philp@oma.be> writes:
> Does anybody knows of an IDL function to test whether a given point is
> inside a polygon?

I needed to solve this recently (in a mapping context). The solution I came up
with works but its not elegant: use poly_fill to actually draw your polygon
(in a pixmap not the screen window if you prefer), then read off the pixel value
of your point to see if its in or out.

This is grotesquely inelegant, but its very simple and it works. I can
post the code if you're interested. A better solution
would be to look at polyfill and see how it does the fill... but sadly
polyfill seems to be one of the few routines not written in IDL.

- William

---
William M Connolley | wmc@bas.ac.uk | http://www.nbs.ac.uk/public/icd/wmc/
Climate Modeller, British Antarctic Survey | Disclaimer: I speak for myself

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[Message index]

		Re: point inside polygon By: LC's No-Spam Newsread on Thu, 09 April 1998 00:00
		Re: point inside polygon By: manizade on Wed, 01 April 1998 00:00
		Re: point inside polygon By: wmc on Wed, 01 April 1998 00:00
		Re: point inside polygon By: Philippe Peeters on Wed, 01 April 1998 00:00
		Re: point inside polygon By: B}rd Krane on Wed, 01 April 1998 00:00
		Re: point inside polygon By: Alex Schuster on Wed, 01 April 1998 00:00
		Re: point inside polygon By: wmc on Wed, 01 April 1998 00:00

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