[GRASS-user] Derivation of Landsat 8 Tasseled Cap coefficients for certain scene in Grass
mlennert at club.worldonline.be
Wed Jun 10 04:56:20 PDT 2015
On 10/06/15 13:18, Nikos Alexandris wrote:
> * Kozlova Maria <kclo at yandex.ru> [2015-06-10 11:48:44 +0300]:
>> Dear colleagues,
>> Thank you for response.
>> a little bit later I will type the full procedure for derivation of TC coefficients.
>> PCA itself cannot be applied here as it is based only on statistical information of the image. TCT is physically based transformation and PCA is only the first step.
>> The main problem I see here is the 'soil line' which must be determined (manually or automatically) and PCA axes rotation to align 1st PCA component in accordance to the soil line.
>> Though I have to describe it in more details later...
> This introduction <http://www.sjsu.edu/faculty/watkins/tassel.htm> looks
> good for me :-)
I don't have access to the paper used for the OLI version, but from the
abstract the authors do "just" use PCA + rotation to get a result that
is as close as possible to a direct tasselled cap transformation using
the original 1970s coefficients.
And when you run PCA on MSS images you often get quite close results to
what Kauth and Thomas arrived at through their clustering approach.
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