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Re: pollyfillv, area of a blob, etc... [message #59646 is a reply to message #59581]

Fri, 04 April 2008 07:18

pgrigis
Messages: 436
Registered: September 2007

Senior Member

JP wrote:
> G'day everyone,
>
> I need to create a mask of pixels contained within a polygon. I tried
> with POLYFILLV, but the problem I have is that my polygons are small
> compared to the pixel size and in some cases there are no pixel
> centers within my polygon and POLYFILLV returns -1.
>
> I found the discussions about this, including "POLYFILLV weirdness",
> "Area of a Blob", etc. For my particular application it doesn't really
> matter the criteria I use for selecting the pixels, but at least I
> need to get the array indices for the pixels that "touch" each
> polygon.

Then you just need to add to the mask all pixels that contain at least
one vertex and you will have solved your problem with small polygons.

Paolo

>
> By the way, ENVI's vector to ROI procedure is probably using
> POLYFILLV as well and I don't get any ROI out of those small
> polygons.
>
> Any help will be very much appreciated.
>
> JP

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[Message index]

		pollyfillv, area of a blob, etc... By: JP on Wed, 02 April 2008 23:16
		Re: pollyfillv, area of a blob, etc... By: pgrigis on Fri, 04 April 2008 07:18
		Re: pollyfillv, area of a blob, etc... By: David Fanning on Fri, 04 April 2008 05:31
		Re: pollyfillv, area of a blob, etc... By: jameskuyper on Fri, 04 April 2008 04:03

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