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Re: plots [message #52821 is a reply to message #31799]

Fri, 02 March 2007 08:13

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

David Fanning writes:

>
>> These are integer pixel coordinates which form a closed boundary of an
>> object, so each pixel will have at least two neighbours. I guess my
>> question is how do you trace the boundary of an object if the all you
>> have is an 2D array of noncontiguous pixel coordinates.
>
> I think the answer was, you don't. At least not in
> any unique way. If you DO want a unique path, you
> are going to have to come up with something other than
> this. :-)

One possibility might be to find the convex hull of these
points. This is not the polygon formed by the points, but rather
the polygon that encloses all the points. Maybe that's good
enough for what you have in mind.

If so, here is an article:

http://www.dfanning.com/tips/convex_hull.html

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

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[Message index]

		plots? By: bin_zheng_99 on Mon, 19 August 2002 15:33
		Re: plots By: David Fanning on Fri, 02 March 2007 08:13
		Re: plots By: ashraf on Tue, 06 March 2007 07:59
		Re: plots By: David Fanning on Fri, 02 March 2007 08:05
		Re: plots By: ashraf on Fri, 02 March 2007 07:57
		Re: plots By: Paolo Grigis on Fri, 02 March 2007 05:18

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