[GRASS-user] r.stream.extract: map mis-match error

[Rich Shepard]

On Fri, 20 Apr 2012, Markus Metz wrote:

> Try to set the region and MASK before the analysis, then don't modify
> these settings during the analysis. Something like
>
> g.region vect=basins align=dem_proj
> g.region res=10m -a
> r.resamp.stats in=dem_proj out=dem_10m method=average -w
> v.to.rast in=basins out=MASK type=area use=val val=1
> r.watershed elevation=dem_10m acc=dem_10m.acc basin=dem_10m.basin
> threshold=150000
> r.mapcalc "dem_10m.acc.w = dem_10m.acc * weight"
> r.stream.extract elevation=dem_10m acc=dem_10m.acc.w
> stream_rast=dem_10m.streams stream_vect=dem_10m_streams threshold=???

   My only modifications to the above were to run r.param.scale after
r.watershed and r.mapcalc to calculate weight from the r.param.scale
tangential curve output maps before calling r.mapcalc to apply the weights.
Could these be problematic?

   The results are still

GRASS 6.5.svn :~/grassdata > r.stream.extract
elev=dem_10m acc=dem_10m.acc.w stream_rast=dem_10m.rstreams.w
stream_vect=dem_10m.vstreams.w thresh=1000 --o
Load input maps and get start points...
ERROR: Accumulation map does not match elevation map!

   I'm completely puzzled ... and a bit frustrated that the same error is
thrown so consistently.

Rich