[GRASS-user] i.maxlik problem
giucillis at gmail.com
Wed Sep 19 03:43:28 PDT 2018
Thanks for the message,
but when I try to run i.cluster with just one raster, the module doesn't
work because: " subgroup need two images" .
Il giorno mar 18 set 2018 alle ore 21:34 Markus Metz <
markus.metz.giswork at gmail.com> ha scritto:
> On Tue, Sep 18, 2018 at 3:38 PM Giuseppe Cillis <giucillis at gmail.com>
> > Hi,
> > I am in the first experiences with GRASS and I have a problem with the
> i.maxlik module.
> > I have to semi-automatically classify two orthophotos already
> geo-referenced and rectified. As a first operation, I create a group and a
> subgroup in which I put the two orthophotos. Next, I create a signature
> with the i.cluster module (initial number of class = 5; iterations = 30;
> percent convergence = 95%; minimum number of pixels = 5). But in the
> resulting output there is a problem because the only classified part is the
> overlap zone between the two orthophotos ... why?
> you need to either classify each orthophoto separately (which is probably
> not what you want) or first patch (the different bands of) the two
> orthophotos together with r.patch, then run i.cluster + i.maxlik. When
> patching the two orthophotos together, make sure the current region covers
> both orthophotos, e.g.
> g.region -p rast=orthophoto1,orthophoto2
> Markus M
> > I hope I was clear
> > GC
> > _______________________________________________
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> > grass-user at lists.osgeo.org
> > https://lists.osgeo.org/mailman/listinfo/grass-user
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