[GRASS-user] Derivation of Landsat 8 Tasseled Cap coefficients for certain scene in Grass

[Kozlova Maria]

Dear Nikos, 
TCT5 may contain atmospheric effects and TCT6 mainly represent noise. Though as far as I know it is not well explored if this information is quite useful.
Maybe it may be valuable in some cases....
 Anyway first 4 components represent most image information.
-- 
Best regards,

Maria V. Kozlova

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10.06.2015, 03:05, "Nikos Alexandris" <nik at nikosalexandris.net>:
> * Kozlova Maria <kclo at yandex.ru> [2015-06-10 00:42:21 +0300]:
>
>>  Dear all,
>>  Asking for help in sudden difficult situation:
>>  I need to derive proper, 'personal', Tasseled Cap coefficients for some scenes of my study area.
>>  I know, such procedure can be done by Matlab, but unfortunately, my colleague who could do this have now some troubles and cannot help me at the moment.
>>
>>  I need to do this work but can use only Grass. So is it possible to derive my own TC coefficients for each scene using Grass? If so, which modules should I use?
>
> First, what is the plan to derive the custom coefficients?
>
>>  Is it possible to do image Tasseled cap transformation with these new coeficients?
>
> Sure, as far as I understand, it's a simple sum. Something similar like (stolen
> from the i.tasscap script):
>
> r.mapcalc "output = k1 * in1band + k2 * in2band + k3 * in3band + k4 * in4band + k5 * in5band + k6 * in6band + k0"
>
>>  Am I right, that Grass module i.tasscap only provide TCT with use of
>>  standard TC coefficients (in the case of OLI images derived by M.H.A
>>  Baig et al, 2014)?
>
> I quickly checked the numbers in the script and the paper by Baig 2014.
> They are the same for *only* Brightness, Greenness, Wetness, TCT4. The
> coefficients for TCT5, TCT6 are missing (compare the numbers in the
> paper, page 428 with
> <https://trac.osgeo.org/grass/browser/grass/branches/releaseb…>).
>
> Are these required? They can be added quickly I think.
>
>>  Would be appreciate for any information
>
> Hope the above helps a bit, Nikos