[GRASS-user] obtaining raster map from point values

Hamish hamish_b at yahoo.com
Tue Jul 14 08:40:21 EDT 2009

Alberto Pettazzi wrote:
> I am trying to obtain a raster map of precipitation derived
> from MSG satellite. I imported in GRASS from a txt file
> containing lon-lat-precipitation values.
> I used
> r.in.xyz
> and what I obtained is the jpeg file attached. As you can
> see, only a series of dots is represented, corresponding to
> the lon-lat-precipitation values contained in the file. what
> can I do in order to convert the dots in something that
> looks more like a "cloud"?
> I also tried
> v.in.ascii + v.to.rast, but the result was almost identical.

I suspect you should try v.in.ascii + v.surf.rst.

v.in.ascii + v.to.rast, or r.in.xyz makes no attempt to
interpolate between data points. So you only see data at exact
stations. You may use one of the v.surf.* or r.surf.* modules
to do the interpolation; using whichever intererpolation method
is most appropriate for your data. See also r.surf.nnbathy and
v.autokridge from addons and v.kridge now in development.



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