[GRASS-user] integration of sample.c algorithms into r.resample

[Maciej Sieczka]

Dylan Beaudette napisa?(a):

> just to follow this above comment up: yes. drop r.bilinear, re-name current 
> r.resample to (?) and create new r.resample based on Gylnn's code

Glynn opts for keeping the old r.resample untouched, and I agree he has
a point. So I won't insist on replacing it, anymore.

Out of other names already suggested, having considered Glynn's
clarifications about interpolation vs resampling, I find r.interpolate
best, in this case.

> - with some 
> fixes for the bicubic case, as it appears to be broken.

Are you refferring to your observations of "weird" slope derivatives of
dems treated with bicubic, ie.

> ##Bicubic
> http://169.237.35.250/~dylan/temp/raster_sampling/c_bc_1m.slope.png

?

If so, how does 'gdawalrp -rc' perform for you? Semething like:

$ r.out.gdal input=dem type=Float32 output=dem.tif

$ gdalwarp -te 589980 4913685 609000 4928040 -tr 1 1 -rc dem.tif
gdal_dem.bic.tif
# you need to control the working window with -te switch explicitely to
# mimic Grass region handling

$ r.in.gdal input=gdal_dem.bic.tif output=gdal_dem.bic
$ r.slope.aspect ...

(I'm asking this becaues I always found 'gdalwarp -rc' output correct,
so the eventuall difference might be a pointer.)

???

Maciek