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Re: Getting ROI data from an image [message #77857 is a reply to message #77853]

Fri, 30 September 2011 14:32

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Rebecca writes:

> That's great, and it makes so much sense, but it doesn't seem like IDL
> obeys those laws of indexing. Using
> temp = img[x,y,*]
> produces an out of memory error. It's not hard to figure out why-
> temp = img[x,y,0]
> Produces a [npix, npix] array, where npix is the number of pixels
> referenced in 'indices'. What I was expecting to happen was a [npix]
> vector! IDL is playing by different rules here.
>
> npix = N_ELEMENTS(indices)
> z = INTARR(npix)
> temp = img[x,y,z]
>
> That produces the magical vector array I want. So, is there any way to
> play by these rules and grab 300 bands worth of data at once so I have
> a [npix, bands] array? Or should I give up the chase and just FOR loop
> it?

Actually, you are doing this correctly by making
your own index vector. See the latter half of
this article:

http://www.idlcoyote.com/misc_tips/submemory.html

Cheers,

David

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

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[Message index]

		Re: Getting ROI data from an image By: Rebecca on Mon, 03 October 2011 06:15
		Re: Getting ROI data from an image By: David Fanning on Fri, 30 September 2011 14:32
		Re: Getting ROI data from an image By: Rebecca on Fri, 30 September 2011 14:16
		Re: Getting ROI data from an image By: David Fanning on Fri, 30 September 2011 13:41
		Re: Getting ROI data from an image By: Rebecca on Fri, 30 September 2011 12:41
		Re: Getting ROI data from an image By: David Fanning on Fri, 30 September 2011 12:19
		Re: Getting ROI data from an image By: Brian Daniel on Fri, 30 September 2011 11:42

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