[GRASS-user] new addon for multivariate surface interpolation from sparse points with smoothing

[Vaclav Petras]

On Fri, Aug 26, 2016 at 12:32 AM, Markus Metz <markus.metz.giswork at gmail.com
> wrote:

> >> If you ever wondered
> >> why worldclim data (http://worldclim.org) follow so nicely elevation,
> >> the reason is multivariate thin plate spline interpolation of
> >> meteorological station data with elevation as a covariate.
> >> [...] The module works only with GRASS 7.2+.
> >
> > It may be useful to note that you can preform similar operation with any
> > version of GRASS GIS using v.vol.rst (3D interpolation using regularized
> > spline with tension). The trick is using cross_* parameters to extract
> the
> > desired 2D raster.
>
> For one covariable, yes, but not for more covariables. E.g. worldclim
> has been interpolated using elevation, latitude and longitude as
> covariables.


...and the results from v.vol.rst are different from v.surf.rst with one
variable (well, the logic/model behind is different). I actually missed
that v.surf.tps can handle multiple covariables, so that's good to know.

And v.vol.rst is rather slow.


I didn't want to post this just yet, but yes, my preliminary tests showed
that v.surf.tps is much faster than v.vol.rst.
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