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Re: How to extract pixel values from a GeoTIFF using an Esri Shapefile [message #74061 is a reply to message #74060]

Sat, 01 January 2011 10:24

Paul Magdon
Messages: 8
Registered: January 2011

Junior Member

On Dec 25 2010, 4:34 pm, David Fanning <n...@dfanning.com> wrote:
> 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.")

Hi,
In my case both the shape and the raster are in UTM projection which
is already a Cartesian projection. So why should I convert them into a
lat/long projection?
@David: I send send you the example files or is there an option to
'post' them here?
Cheers Paul

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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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