I would like to be able to sample a raster map using bilinear
interpolation at points in a vector map. I want the resulting raster
value to end up in an attribute column of the vector map. With existing
6.3 tools, this becomes a several step process.v.what.rast does what I need, but only with nearest neighbor sampling.
I could use v.sample, but that creates a new map/table, and the only
way to get the attribute back to the original map is to use an SQL
join, which is unsupported in dbf and sqlite databases. v.drape could
also be used, but it also creates a new vector map, which has to
replace the original, and sometimes the raster information does not
make sense as a Z-coordinate.I've made some changes to v.sample so that it will update a column (and
not create a new map). However, I think the cleanest approach would be
to have a new option for v.what.rast. Furthermore, IMHO, v.rast.what
should, through options, do whatever v.sample does and v.sample should
be be eliminated.
v.buffer + v.rast.stats? Then if you like attach v.buffer centroid
attributes to original points with v.distance or just extract the
centroids and convert them to points (v.extract + v.type).
Hamish