[GRASS-user] i.atcorr for GeoEye-1 and Worldview-3

Kamhul Camhol monk_purple at yahoo.com
Wed Jun 3 19:27:58 PDT 2015


Dear Nikos,
Thanks for the advice! The imagery are Ortho-Ready Standard 2A, already radiometrically and sensor-corrected but not atmospherically and geometrically corrected. Are they already in radiance or reflectance values? Sometimes, I am confused as radiometric correction appears to be interchanged or taken similarly with atmospheric correction. 

Anyway, of course I would be willing to support the testing as you said. May I know how this is done?
 



     On Thursday, June 4, 2015 12:28 AM, Nikos Alexandris <nik at nikosalexandris.net> wrote:
   

 * Kamhul Camhol <monk_purple at yahoo.com> [2015-06-03 04:56:37 +0000]:

> Hello. I'm quite new with GRASS but I need to atmospherically process high-resolution imagery with i.atcorr. I have three images Quickbird, GeoEye-1 and Worldview-3 imagery of a single scene across three time periods.

Hi!

You would need, I think, to convert the raw Digital Numbers first to
radiance/reflectance values. Please have a look at [0][1].


> For Quickbird, I have all the data needed but basing from the following manual GRASS GIS manual: i.atcorr  there appears to be novalues for two required inputs for GeoEye-1 and Worldview-3.

I have prepared months ago the numbes for QB2 and WV2 Yet, there has been no successful test so far (from my side at
least). I need to try again :-/. Are you willing to support testing?


> These are geometrical conditions and band. May I know if GRASS has updated the i.atcorrmanual to include these sensors as well?

> Can I use the values ofWorldview-2 for Worldview-3?

I think not. We need to get the radiometric response values for WV3.
Then we can prepare the required data for i.atcorr.  But, as with the
other two, it needs testing.

> Or is there any other way to do the atmospheric correction for these two sensors?

There are other tools that could do this. I think ORFEO ToolBox is one
(from which I stole the numbers for QB2 back then).

Yet, having this option in GRASS will make the workflow easier. We need
it.

Nikos

  
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