[GRASSLIST:4590] Re: aggregate a higher resolution to a lower resolution

[Ulrich Leopold]

which version has the s.cellstats? 5.1? I have currently 5.0.0pre5.

The problem about s.windavg is I will not get the variance. But maybe it's a 
good idea to convert to an ascii file and do the aggregation outside grass 
with awk etc..

Thanks very much,
Ulrich

Gordon Keith wrote:
> On Thu, 26 Sep 2002 18:45, Glynn Clements wrote:
> 
>>Ulrich is looking for something which maps multiple input cells to a
>>single output cell. Similar to r.resample/r.resamp.rst, but using an
>>average rather than nearest-neighbour (r.resample, i.e. the automatic
>>resampling built into the libgis raster functions) or spline
>>interpolation (r.resamp.rst).
>>
>>Unfortunately, this isn't straightforward (or efficient) to
>>implement, as libgis' raster handling assumes a common region and
>>resolution (i.e. cellhd) for all input and output maps.
>>
>>The easiest approach would be r.neighbors to perform the average,
>>followed by g.region/r.resample to downsample the data. *Except* that
>>r.neighbors only allows odd-sized windows (so that there is an
>>unambiguous "centre" cell).
> 
> 
> 
> How about:
> r.to.sites
> g.region
> s.windavg (or the new s.cellstats)
> s.to.rast
> 
> Regards
> Gordon
>