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Re: How to extract pixel values from a GeoTIFF using an Esri Shapefile [message #74078 is a reply to message #74061]

Sat, 25 December 2010 07:34

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Paul Magdon writes:

> I tried your suggestion to use ROI_XRANGE and got the following Error:
> % Keyword ROI_XRANGE not allowed in call to: OBJ_NEW
> As fare as I understand the IDL documentation ROI_XRANGE can not be
> set for an IDLanROI object.

Ah, right, I didn't notice that. Sorry. :-)

OK, then I suppose you have to convert the pixel
locations into the same units as the ROI (probably
lat/lon). If your image coordinates are in projected
XY space, then you put them into lat/lon space with
Map_Proj_Inverse. Map_Proj_Forward goes the other way.

I tend to *always* work in projection XY space, so
I would probably convert the shape file to these
coordinates before I stored them in the ROI.

Anyway, if you send me the files, I'll write up an
example for you, although I can't promise to be
quick about it, unfortunately. Too much going on
here, and money is running out faster than my
fingers can type. :-)

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]

		Re: How to extract pixel values from a GeoTIFF using an Esri Shapefile By: David Fanning on Sat, 01 January 2011 10:32
		Re: How to extract pixel values from a GeoTIFF using an Esri Shapefile By: Paul Magdon on Sat, 01 January 2011 10:24
		Re: How to extract pixel values from a GeoTIFF using an Esri Shapefile By: David Fanning on Sat, 25 December 2010 07:34
		Re: How to extract pixel values from a GeoTIFF using an Esri Shapefile By: Paul Magdon on Sat, 25 December 2010 05:32
		Re: How to extract pixel values from a GeoTIFF using an Esri Shapefile By: David Fanning on Thu, 23 December 2010 13:34
		Re: How to extract pixel values from a GeoTIFF using an Esri Shapefile By: Paul Magdon on Mon, 03 January 2011 04:30

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