[GRASS-dev] new flag to interpolate from nearby raster cells for v.what.rast

[Markus Metz]

On Thu, Nov 14, 2013 at 11:15 AM, Hamish <hamish_b at yahoo.com> wrote:
> Hi,
>
> I just added in the dev branches two new flags for v.what.rast.
> [...]
>
> The second flag changes the default containing-grid-cell method to a
> weighted avg. of the 4 nearest raster cell centers (IDW). The search radius
> is not very big [...]

AFAIK, IDW takes as argument the radius which is fixed to 1 which is
questionable. Since v.what.rast samples a raster value at a given
location, why not use the standard raster sampling methods
                nearest: nearest neighbor
                linear: linear interpolation
                cubic: cubic convolution
                lanczos: lanczos filter
                linear_f: linear interpolation with fallback
                cubic_f: cubic convolution with fallback
                lanczos_f: lanczos filter with fallback

which are used by r.proj and i.rectify? The concept is essentially the
same: for a given location, estimate the corresponding raster value.

Markus M