| Tasselated Cap in IDL? [message #81191] |
Mon, 20 August 2012 09:59  |
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DavidF[1]
Messages: 94
Registered: April 2012
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Member |
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Folks,
Has anyone implemented a Tasselated Cap algorithm for LandSat data in IDL? I realize this exists in ENVI, but I am looking for an IDL-only solution.
Thanks,
David
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| Re: Tasselated Cap in IDL? [message #81219 is a reply to message #81191] |
Wed, 29 August 2012 05:45  |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Yngvar Larsen writes:
> Sorry for late answer, but since nobody answered yet...
> (Though likely you already resolved this by yourself,
> since Google knows the answer.)
Yes, but like most things, the answer is a little bit
more complicated than you think it is going to be. :-)
Anyway, I've written a cgTasseledCap function that goes
along with a cgTasseledCapCoeffs function that can
return a number (eight, if I remember correctly) of tasseled
cap matrices with coefficients for performing the
operation, depending upon what kind of data you have.
Most of the coefficients apply to various types of LandSat data,
but there are some Quickbird coefficients there as well.
I haven't officially released the code yet, as I am still
testing it. But, I'm reasonably sure it is working correctly.
Look for it by the end of the week.
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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| Re: Tasselated Cap in IDL? [message #81222 is a reply to message #81191] |
Tue, 28 August 2012 23:09 |
Yngvar Larsen
Messages: 134
Registered: January 2010
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Senior Member |
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On Monday, 20 August 2012 18:59:19 UTC+2, Coyote wrote:
> Folks,
> Has anyone implemented a Tasselated Cap algorithm for LandSat data in IDL? I realize this exists in ENVI, but I am looking for an IDL-only solution.
Sorry for late answer, but since nobody answered yet... (Though likely you already resolved this by yourself, since Google knows the answer.)
Not sure what your actual problem is? The Tasseled Cap transformation is just a linear combination of (a selection of) the bands of a multispectral imager. So the actual IDL code would be something you literally implement in 2 minutes. So I guess you are looking for the weights to use? That of course depends on which Landsat data you have.
For Landsat TM and the older Landsat MSS, there is a useful summary here: http://www.sjsu.edu/faculty/watkins/tassel.htm
For Landsat 7 ETM+, you can try Table 2 in the following document:
http://landcover.usgs.gov/pdf/tasseled.pdf
--
Yngvar
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