[GRASS-user] i.atcorr (6S): implementing new airborne hyperspectral sensor

[Markus Neteler]

Hi Alexander,

On Wed, Jul 15, 2015 at 9:01 AM,  <stu112827 at mail.uni-kiel.de> wrote:
> Hello dear GRASS Users,
>
> I would like to carry out an atmospheric correction of some AISA Eagle data
> with 6S. It's a hyperspectral, airborne sensor. There are 60 bands in the
> range from 405 to 951 nm (about a 9,2 nm - step).
>
> So my question(s)... Is it possible to implement a new hyperspectral,
> airborne sensors in i.atcorr? I know there is already a hyperspectral
> satellite sensor included.

I'm not quite sure if *airborne* sensors can be added to 6S.
Did you find any research papers on that?

> If it is possible, how much time will be roughly consumed to undertake this
> task? Days, weeks or months?

Rather days (hours?) that anything else *if* it is possible.

> Furthermore, I've already read the i.atcorr README to "add new band filters"
> (http://trac.osgeo.org/grass/browser/grass/trunk/imagery/i.atcorr/README),
> but I'm an absolute beginner, so unfortunately I wasn't able to  figure out
> how to create the needed filter function.

In general:
You need to obtain the spectral curves of each band from the sensor provider.
This is then turned into a simple style formatted kind of ASCII table
and added to the software.
Essentially you need to write out the various spectral curves as CSV
table. See for example

https://trac.osgeo.org/grass/browser/grass/branches/releasebranch_7_0/imagery/i.atcorr/sensors_csv

Then use the create_iwave.py script which is in the parent directory
to turn the tables into code to be added to the iwave.cpp file, then
add the sensor to the sensor list and manual (see the README) and
recompile.

hope this helps
Markus