On Thu, Jun 28, 2018 at 2:23 PM, Stefan Blumentrath < stefan.blumentr...@nina.no> wrote: > > 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?
feed the visibility map as input to i.atcorr with the visibility option. The corresponding options in the 6s input file are then ignored by i.atcorr. > > 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. such a long manual, and still not complete... If a visibility map is provided, the parameters regarding AOD at 550nm in the 6s input file are ignored. I added a short note in trunk r72917. Markus M > > > > 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.gisw...@gmail.com> > Sent: torsdag 28. juni 2018 14:09 > To: Stefan Blumentrath <stefan.blumentr...@nina.no> > Cc: Yann Chemin <dr.yann.che...@gmail.com>; mlenn...@club.worldonline.be; GRASS-dev <grass-dev@lists.osgeo.org>; Roberta Fagandini < robifagand...@gmail.com> > > > Subject: Re: [GRASS-dev] compile 6S library in GRASS > > > > > > On Thu, Jun 28, 2018 at 2:03 PM, Stefan Blumentrath < stefan.blumentr...@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-boun...@lists.osgeo.org> On Behalf Of Yann Chemin > > Sent: torsdag 28. juni 2018 13:38 > > To: mlenn...@club.worldonline.be > > Cc: Markus Metz <markus.metz.gisw...@gmail.com>; GRASS-dev < grass-dev@lists.osgeo.org>; Roberta Fagandini <robifagand...@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 < mlenn...@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@lists.osgeo.org > > https://lists.osgeo.org/mailman/listinfo/grass-dev
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