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Re: image interplate and overlay lat/lon? [message #81177 is a reply to message #81176]

Wed, 22 August 2012 09:26

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

go cats writes:

> My goal is to take an image(s) and overlay geographic lat/lon information onto the image. I have lat/lon information of four boundaries and tried to create a regular grid using them.
>
> I?ve used David?s code to generate a regular lat/lon grid, and tried to interpolate image with gridded lat/lon data.
>
> However, outImage looks blank and only geographin lat/lon data are shown with 0 image pixel values. I am working on 8-bit tif images.
>
> Would anybody give me some tips how to make this work or what I did wrong?

Maybe there are GeoTiff files that use latitude and longitude values for
the tie points and scales, but I've never seen any. All the GeoTiff
files I've ever worked with use projected meter values and include
information about the map projection in the file.

You shouldn't have to do any image interpolation. Basically,
what you want to do it just fit a projected map grid around
the image itself.

http://www.idlcoyote.com/map_tips/ephemeral.php

Then, you put the parameters of the grid into the appropriate
spots in your geoTiff structure and you are good to go.

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: image interplate and overlay lat/lon? By: beardown911 on Wed, 22 August 2012 10:13
		Re: image interplate and overlay lat/lon? By: David Fanning on Wed, 22 August 2012 09:49
		Re: image interplate and overlay lat/lon? By: David Fanning on Wed, 22 August 2012 09:26
		Re: image interplate and overlay lat/lon? By: Yngvar Larsen on Mon, 27 August 2012 03:49

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