[GRASS-user] interpolating with a covariate - v.vol.rst

Dylan Beaudette dylan.beaudette at gmail.com
Wed Jan 7 11:19:37 EST 2009


On Tue, Jan 6, 2009 at 2:33 PM, Markus Neteler <neteler at osgeo.org> wrote:
> Dylan,
>
> On Tue, Jan 6, 2009 at 10:01 PM, Dylan Beaudette
> <debeaudette at ucdavis.edu> wrote:
>> Hi,
>>
>> For some crazy reason I was under the impression that it is possible to do
>> interpolation with a covariate with v.vol.rst. Are there any examples on how
>> to parameterize this module, when a 2D surface is requested, rather than a 3D
>> volume. I noticed the 'cellinp' argument for a cross-section, but this is not
>> quite what I am after. I am looking to do something very similar to
>> interpolation of rainfall data, taking into account the orographic effect of
>> terrain.
>
> This was my main business (say, of our cluster) over the last months :)
> You can do that. I am using the elevation model as auxiliary variable:
>
> # something like this:
> v.vol.rst in=vectpoints cellinp=dem wcolumn=pointval cellout=rst2d
>
> cellout delivers the 2D map, extracted from the volume along the
> dem map.
>
> Hope this helps
> Markus
>

Thanks Markus. One more question: have you found a good compromise in
the 3D region settings- i.e. some ratio of horizontal:vertical
resolution that gives good results and doesn't take too long to
compute?

Cheers,

Dylan


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