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
<[email protected]> wrote:
* Kamhul Camhol <[email protected]> [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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