| Re: Mosaic_doit in IDL gives a different result that the ENVI mosaic tool [message #69458] |
Thu, 07 January 2010 08:26 |
Mort Canty
Messages: 134
Registered: March 2003
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Senior Member |
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Am 07.01.2010 14:14, schrieb David Fanning:
>
> I don't know anything about this particular problem, but
> it has been my experience with ENVI's mapping routines
> that the functionality available through ENVI's GUI can
> be different than the functionality available through its
> API routines. So much so, that I feel confident in saying
> that ENVI doesn't always use its own API.
Amen to that. I recall that the first version of ENVI_SVM_DOIT didn't do
it, while the GUI did do it :-)
Mort
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| Re: Mosaic_doit in IDL gives a different result that the ENVI mosaic tool [message #69464 is a reply to message #69458] |
Thu, 07 January 2010 05:14  |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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laureroupioz writes:
> I have a question regarding the mosaic_doit command in IDL. I used
> this command to mosaic several images extracted from Modis hdf data
> using the Modis conversion toolkit. In order to valid the result
> obtained using IDL, I mosaicked the same images using the mosaicking
> tool in ENVI. The results are quite similar however the pixel values
> can slightly vary between the two methods. I tried to look at all the
> parameters that can be set in mosaic_doit but I don?t understand where
> this difference comes from. When looking closer at the result, the
> pixel size of the 2 outputs is the same however the number of rows and
> columns is different, the mosaic performed in ENVI present one row and
> one column more. Then I assume that the difference comes from a shift
> in pixels due to this lacking column and row. By comparing with the
> original image the result of ENVI seems to be the correct one. Do you
> think the problem could come from the georef_mosaic_setup script? Do
> you know how I could solve this problem in IDL?
I don't know anything about this particular problem, but
it has been my experience with ENVI's mapping routines
that the functionality available through ENVI's GUI can
be different than the functionality available through its
API routines. So much so, that I feel confident in saying
that ENVI doesn't always use its own API. Or, at the very
least, tweaks are made to it that are not available to the
API user. This could be something like that. I've always
found ITTVIS to be responsive to direct inquiries about
this kind of thing.
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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