Dear Yann Chemin,
have many thanks for your reply regarding i.dn2full.l5/17:
The background of my question was that we want to calculate
evapotranspiration from desert and semi desert areas. According to your
and other users' experience, which add on performs better:
i.evapo.potrad, i.evapo.senay, or i.eb.evapfr ?
Regarding the required input parameter for i.evapo.potrad and
i.evapo.senay, can I use r.albedo and where do I find it ? Can I derive
the surface skin temperature through i.dn2full.l5/17 ? I was wundering
because in the description for i.dn2full.l5/17 there was written that DN
is calculated into radiance at top of the athmosphere. Furthermore, what
is the single way transmissivity ?
Best regards
Niels
Yann Chemin schrieb:
Hi Niels,
in grass-Addons/gipe/ there are a couple of functions to get L1b
Landsat 5/7 into radiant temperature at top of atmosphere.
i.dn2full.l5
i.dn2full.l7
this corrects standard images having .met standard metadata file or
NLAPS metadata (.txt) file.
You may try and see if you get to some useful ends.
You may also see some fast method to get surface temperature from this
product by using emissivity. As it was used for AVHRR 15 years ago.
in Grass-Addons, i.landsat.toar may also help you out, but it is a
long time I have had a look at it.
Cheers,
Yann
2008/9/25 Niels Thevs <[EMAIL PROTECTED]>:
Dear Grass users,
does anybody have experience with the calibration of the Landsat thermal
data ? I have a few ground measurements of temperature (air temperature in 2
m above surface) and want to relate them to a corresponding Landsat image
(band 6). In the papers which I read there are listed a lot of working steps
like calibration for at sensor radiance, surface radiance, etc. Is it
necessary to do all those steps or does anybody know a more simple algorithm
?
Best regards
Niels
--
-----------------------------------------------------
Dr. Niels Thevs
Chair of Geobotany and Landscape Ecology
Institute of Botany and Landscape Ecology
Greifswald University
Grimmer Strasse 88
17487 Greifswald
Germany
Tel.: +49-3834-86-4137
Fax: +49-3834-86-4114
-----------------------------------------------------
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--
-----------------------------------------------------
Dr. Niels Thevs
Chair of Geobotany and Landscape Ecology
Institute of Botany and Landscape Ecology
Greifswald University
Grimmer Strasse 88
17487 Greifswald
Germany
Tel.: +49-3834-86-4137
Fax: +49-3834-86-4114
-----------------------------------------------------
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grass-user mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/grass-user
