[GRASS-user] exporting single banded float raster to true color geotiff (i.e. 3 Byte bands with color interpretation)

[G. Allegri]

I Thanks Markus, I didn't know I could export image groups directly from
r.out.gdal. The GUI doesn't list image groups from the available inputs... I
will tell Martin.

giovanni

2011/9/19 Markus Metz <markus.metz.giswork at googlemail.com>

> On Mon, Sep 19, 2011 at 11:15 AM, G. Allegri <giohappy at gmail.com> wrote:
> > Thanks Hamish, r.out.tiff did the work. I already had tried it but I
> failed
> > because I dind't set the region correctly.
> > Anyway, setting the -t flag writes the TFW but doesn't make it a *true*
> > GTiff, because r.out.tiff writes a Baseline tiff, without the GTiff tags.
> > But that isn't a problem of course, I can produce a GTiff with another
> step
> > (eg gdal tools).
>
> You can export a true GTiff with color as cell values instead of
> original cell values with
>
> # extract RGB values
> r.mapcalc "mymap.r = r#mymap; mymap.g = g#mymap; mymap.b = b#mymap"
>
> # create RGB group
> i.group group=mymap.rgb in=mymap.r,mymap.g,mymap.b
>
> # export RGB group
> r.out.gdal in=mymap.rgb out=mymap.tif -c
>
> The -c flag to skip export of the colortable because the raster values
> themselves hold the color info.
>
> Markus M
>
> > giovanni
> >
> > 2011/9/17 Hamish <hamish_b at yahoo.com>
> >>
> >> Giovanni wrote:
> >> > The question is the object :)I have a Float raster which GRASS
> >> > displays with a certain color table (I haven't set it...
> >> > PS: what table is used by default?). What's the most effective
> >> > way to export the raster into a true color Geotiff (as a 3 Byte
> >> > bands with color interpretation) using a certain color table?
> >>
> >> I believe that r.out.tiff will export using colors, not data.
> >> Add the -t flag to get a world file & so make it a geotiff.
> >>
> >> In GRASS 6.4 the d.out.file module is another option, set the
> >> size= parameter to the number of rows and columns, and select
> >> format=geotiff.
> >>
> >> The default color table is "rainbow", see the r.colors help page
> >> for details.
> >>
> >>
> >> Hamish
> >
> >
> > _______________________________________________
> > grass-user mailing list
> > grass-user at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/grass-user
> >
> >
>
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