[GRASS-user] Interpolation of regular gridded continous data

[Markus Neteler]

On Mon, Mar 31, 2014 at 11:16 AM, Christian Willmes
<c.willmes at uni-koeln.de> wrote:
> Hello,
>
> I want to interpolate a regular 1° x 1° temperature (°K) data vector
> point grid to a higher resolution, say a regular 0.1° x 0.1° raster grid.
>
> I assume that the temperature data is continous and the data between the
> cells should be interpolated as if they were on a straight gradient
> line/plane between the given 1° points, by keeping the originial input
> value for the given points (on the 1° x 1° grid).
>
> What would be the best interpolation method in GRASS to get this result?
>
> I assume, a simple bilinear interpolation would be fine? Is that
> correct?

Yes, I think so: you should just be aware that a "lot" of increase
needs to be supported by information, otherwise it is pure cosmetics.

see
http://grasswiki.osgeo.org/wiki/Interpolation#Resampling_of_raster_maps_to_finer_resolution

> Which tool does this from vector points (r.bilin only takes
> raster)?

Be sure to use a fresh GRASS version.

If you have points, you can use the fast module
* Interpolating from vector points with B-splines (v.surf.bspline)

Best
Markus