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Re: Map to data coordinate conversion [message #83927 is a reply to message #83926]

Thu, 18 April 2013 08:12

chris_torrence@NOSPAM is currently offline

chris_torrence@NOSPAM
Messages: 528
Registered: March 2007

Senior Member

On Thursday, April 18, 2013 8:19:48 AM UTC-6, Paul Mallas wrote:
> Hello all,
>
>
>
> I am looking to convert, given a geotff image with map info, the lat/lon data to a pixel location in an image.
>
>
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> What I want to do seems pretty easy, but I am having a hard time coding it in IDL for some reason. I must be missing something.
>
>
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> Using the ENVI() API, this was straight forward:
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>
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> oEnvi = envi(/headless)
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> eMask = oEnvi->openRaster(file)
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> fid = ENVIRasterToFID(eMask)
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> envi_convert_file_coordinates, fid, xf, yf, lon, lat
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>
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> with lon, lat being my predefined input and xf, yf being my desired output.
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> The analogous way to do this in IDL is (I think):
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> img = image(file, /buffer)
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> xy = img->convertcoord(lon, lat, /to_data)
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>
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> however the image() function won't read the geotiff properly (but ENVI() accepts it just fine). Perhaps my geotiff tag is not properly formed or something. Ideas on another way?

Hi Paul,

I think you want to use the MapForward method. Something like this:

i = image(FILEPATH('boulder.tif',SUBDIR=['examples','data']))
print, i.mapforward(-105,40)

The ConvertCoord is just for converting between screen/normalized/data coordinates, and not between lat/lon and data.

Hope this helps.
-Chris
ExelisVIS

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[Message index]

		Re: Map to data coordinate conversion By: PMan on Thu, 18 April 2013 08:27
		Re: Map to data coordinate conversion By: Fabzi on Thu, 18 April 2013 08:20
		Re: Map to data coordinate conversion By: PMan on Thu, 18 April 2013 08:15
		Re: Map to data coordinate conversion By: chris_torrence@NOSPAM on Thu, 18 April 2013 08:12
		Re: Map to data coordinate conversion By: David Fanning on Thu, 18 April 2013 07:40
		Re: Map to data coordinate conversion By: David Fanning on Mon, 22 April 2013 05:20
		Re: Map to data coordinate conversion By: chris_torrence@NOSPAM on Fri, 19 April 2013 16:06

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