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 <[email protected]> Sent: torsdag 28. juni 2018 14:09 To: Stefan Blumentrath <[email protected]> Cc: Yann Chemin <[email protected]>; [email protected]; GRASS-dev <[email protected]>; Roberta Fagandini <[email protected]> Subject: Re: [GRASS-dev] compile 6S library in GRASS On Thu, Jun 28, 2018 at 2:03 PM, Stefan Blumentrath <[email protected]<mailto:[email protected]>> 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 > <[email protected]<mailto:[email protected]>> > On Behalf Of Yann Chemin > Sent: torsdag 28. juni 2018 13:38 > To: [email protected]<mailto:[email protected]> > Cc: Markus Metz > <[email protected]<mailto:[email protected]>>; > GRASS-dev <[email protected]<mailto:[email protected]>>; > Roberta Fagandini <[email protected]<mailto:[email protected]>> > 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 > <[email protected]<mailto:[email protected]>> 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 > [email protected]<mailto:[email protected]> > https://lists.osgeo.org/mailman/listinfo/grass-dev
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