[GRASS-dev] compile 6S library in GRASS

[Stefan Blumentrath]

Thanks for clarification, Markus.

So, what would a module that puts together an 6s input file (which is what Roberta is about to produce if I understood correctly) have to do with a visibility map then? Nothing, probably?

Would visibility values in the 6s parameter file be overwritten if a AOD map is provided to i.atcorr?
The i.atcorr manual[1] is not particularly clear on this…
In fact handling of visibility map is mentioned as a remaining documentation issue in the manual.

Maybe something you could have a look at in your GSoC project, Roberta?

Cheers
Stefan

1: https://grass.osgeo.org/grass75/manuals/i.atcorr.html

From: Markus Metz <markus.metz.giswork at gmail.com>
Sent: torsdag 28. juni 2018 14:09
To: Stefan Blumentrath <Stefan.Blumentrath at nina.no>
Cc: Yann Chemin <dr.yann.chemin at gmail.com>; mlennert at club.worldonline.be; GRASS-dev <grass-dev at lists.osgeo.org>; Roberta Fagandini <robifagandini at gmail.com>
Subject: Re: [GRASS-dev] compile 6S library in GRASS



On Thu, Jun 28, 2018 at 2:03 PM, Stefan Blumentrath <Stefan.Blumentrath at nina.no<mailto:Stefan.Blumentrath at nina.no>> wrote:
>
> Just one quick follow up question regarding your wild guess:
>
>
>
> With a raster map option, the module would have to make assumptions on units / scale of values in the map (documented in the manual), so in the further process e.g. average or median could be extracted (r.univar) and fed to 6s input file, right?

no, i.atcorr accepts a visibility raster map as input, equivalent to aerosol optical depth at 550nm.

Note that internally i.atcorr converts AOD at 550nm to visibility with
v = exp(-log(taer55 / 2.7628f) / 0.79902f);

Markus M
>
>
>
> Cheers
>
> Stefan
>
>
>
>
>
> From: grass-dev <grass-dev-bounces at lists.osgeo.org<mailto:grass-dev-bounces at lists.osgeo.org>> On Behalf Of Yann Chemin
> Sent: torsdag 28. juni 2018 13:38
> To: mlennert at club.worldonline.be<mailto:mlennert at club.worldonline.be>
> Cc: Markus Metz <markus.metz.giswork at gmail.com<mailto:markus.metz.giswork at gmail.com>>; GRASS-dev <grass-dev at lists.osgeo.org<mailto:grass-dev at lists.osgeo.org>>; Roberta Fagandini <robifagandini at gmail.com<mailto:robifagandini at gmail.com>>
> Subject: Re: [GRASS-dev] compile 6S library in GRASS
>
>
>
> a wild guess: specify a raster input option for AOT (alongside other options), let user find its image source and use it.
>
>
>
> Very limited requirement for the GSoC student, most latitude for the the modules user.
>
>
>
> ----------
> Dr. Yann Chemin
>
> Freelancer
>
> +33 7 83 85 5234
>
> 3 Toulmelin, 56400 Plumergat, FR
>
> https://www.paypal.me/yannchemin
>
>
>
>
>
> On Thu, 28 Jun 2018 at 13:35, Moritz Lennert <mlennert at club.worldonline.be<mailto:mlennert at club.worldonline.be>> wrote:
>
> On 28/06/18 12:17, Roberta Fagandini wrote:
> > I'm not an expert in MODIS data so if someone wants to give
> > suggestions about how to retrieve the AOT from these data, I will
> > definitely add this option too.
>
> I'm not an expert, and MarkusM can probably provide you with more info,
> but you can already see https://lpdaac.usgs.gov/node/1265.
>
> Moritz
>
>
> _______________________________________________
> grass-dev mailing list
> grass-dev at lists.osgeo.org<mailto:grass-dev at lists.osgeo.org>
> https://lists.osgeo.org/mailman/listinfo/grass-dev
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/grass-dev/attachments/20180628/477f82e3/attachment-0001.html>