[GRASS-user] Estimating Albedo from Landsat

Hamish hamish_b at yahoo.com
Mon Sep 13 08:27:46 EDT 2010

> Did you finally used i.landsat.toar for the Landsat5 - TM bands?

I haven't tried with landsat 5 data from glovis yet, have some scenes
on order, expect them to arrive in the next few days. It seems to be
working for me with landsat7 data. Band 61 temperatures seem plausible
anyway & metadata file is read cleanly.
> I am trying to use the module on the LT51830332007248MOR00
> image(s) and have  several (expected) problems, like:
> (note that the metadata file I downloaded via GLOVis has a
> ".meta" extension)
> 1. the "LT51830332007248MOR00.meta" isn't read correctly or
> the module is  looking for a string other than the "date_acquired =
> 20070905" string which is the only "date-string" included in the ".meta"
> file
> 2. does not recognize the solar elevation value
> (the above "cases" are mentioned in the manual, so manual
> feed is required  here)
> 3. after manually providing the "solar_elevation" and the
> "product_date" and using the "-v" flag, some random (?) segfaults occur.

I am a bit suspicious of the if(flag->answer) bits of the code, if pointers
and boolean integers are getting mixed up.

I think over the next week or two I'll continue to make small cleanups and
improvements to the i.landsat.toar and i.landsat.acca code.

> 4. without the "-v" flag it runs but seems to take too much
> time? OK, the image set is large ( 7654 cols x 7127 rows x 7 bands). ---
> Is it really taking so long or is there something wrong?

how much time? for me it takes a few minutes.



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