[OSGeo-Discuss] Built a mask

[Richard Greenwood]

Elena,

I have not worked with a GRASS mask for many years, but my
recollection is that any raster layer can be a mask if you just name
it as such. You might get more responses if you pose your question on
the GRASS user's list
    http://grass.fbk.eu/community/support.php
This list is for more general Open Source Geospatial discussion than
for questions specific to a particular software.

Rich

On Thu, Feb 16, 2012 at 10:28 AM, Elena Bastianon
<elena.bastianon at gmail.com> wrote:
> Hello,
> What I must do is create a mask in GRASS which takes consideration on the
> slope of the study area.
> I'm studying a river and I have the GDEM of the area, what I've done so far
> it was extrapolate some sections in order to have the longitudinal profile /
> slope (and that is a line), to do that I used the GDEM, following the main
> channel line's.
> Now my problem  is how to transform this informations in a surface.
> My idea would be to create something like a GDEM from the longitudinal
> profile (I tried with v.surf.rast) and then with r.mapcalc get the mask
> (with r.mapcalc, define the mask choosing the points of the GDEM which are
> located at an altitude of about 5-6m larger than that of the longitudinal
> profile).
>
> Does anyone have any suggestions?
>
> Thanks in advance for availability
> Have a nice day
>
> --
> Elena
>
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-- 
Richard Greenwood
richard.greenwood at gmail.com
www.greenwoodmap.com