[GRASS-dev] r.resamp.stats method=sum artifacts

Hamish hamish_nospam at yahoo.com
Mon Oct 30 23:00:06 EST 2006

Glynn Clements wrote:
> Hamish wrote:
> > with "r.resamp.stats method=sum", I'm seeing banding. Is this
> > expected or a case of it including points falling on the northern
> > and eastern bounds? so the same input cell gets counted for multiple
> > output cells? i.e. is it doing ( <= x <= , <= y <= ) instead of ( <=
> > x < , <= y < ) ?
> Unless the destination resolution is an integer multiple of the source
> resolution, the total number of source cells used for each destination
> cell will vary.
> E.g. if the source resolution is 10m, and the destination resolution
> is 25m, then the output cells will be based upon grids of 2x2, 2x3,
> 3x2 and 3x3 source cells, in equal proportions.
> The banding effect should go away if you use the -w switch. That will
> cause the aggregates to use proportional fractions of each source
> cell's value, rather than attributing the entire source cell to
> whichever destination cell contains the source cell's centre.

Yes, adding the -w flag did the trick now it looks good. Both slope and
curvature derivatives are perfectly clean as well.


ps - I've added metadata (hist/) support to r.resamp.stats & .interp,
and they now copy over the source map's color table, for all cases but

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