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Re: Locate pixels that fall within other pixel-geo search [message #72438]

Sat, 11 September 2010 09:16

rogass
Messages: 200
Registered: April 2008

Senior Member

On 11 Sep., 15:07, tegus <tegusbillhar...@gmail.com> wrote:
> On Sep 9, 4:07 pm, Snow53 <jennifer_wa...@hotmail.com> wrote:
>
>
>
>
>
>> Hi,
>
>> I have two images with slightly different dimensions, but the same
>> projection. Image 1 has coarse resolution. Image 2 has fine
>> resolution.
>
>> For each coarse pixel in Image 1, I need to find all fine resolution
>> pixels that fall within that pixel (based on the condition that they
>> fall within the same geographic extent of that coarse pixel).
>
>> I'm reading in the file with envi_open_file, so the files should have
>> all the geographic info needed.
>
>> Has anyone done something similar? Could anyone suggest a good way to
>> do this selection?
>
>> Thanks!
>
> Hi!
>
> In IDL you could do this using J.D. Smith's Hist_nd histogram routine
> which is available on David Fanning's website (dfanning.com). While on
> David's website you'll also want to check out JD Smith's HISTOGRAM:
> The Breathless Horror and Disgust.
> The way I work this problem is to rebin the fine resolution image
> (i.e., 2D histogram) to match the resolution (binning) of the coarse
> image (coverage and projection of the two images need to coincide).
> The key is to create a reverse index array using the REVERSE_INDICES
> keyword of Hist_nd. The reverse index allows you to look up the
> contents of each bin in the new histogram, based on the finer
> resolution, at the coarser resolution.
>
> Bill

Cool Way! Really.

Regards

Chris

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[Message index]

		Re: Locate pixels that fall within other pixel-geo search By: rogass on Sat, 11 September 2010 09:16
		Re: Locate pixels that fall within other pixel-geo search By: tegus on Sat, 11 September 2010 06:07
		Re: Locate pixels that fall within other pixel-geo search By: Maxwell Peck on Fri, 10 September 2010 01:28
		Re: Locate pixels that fall within other pixel-geo search By: rogass on Thu, 09 September 2010 13:41

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