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

Markus Metz markus.metz.giswork at googlemail.com
Fri Apr 20 12:28:24 EDT 2012

On Fri, Apr 20, 2012 at 6:22 PM, Rich Shepard <rshepard at appl-ecosys.com> wrote:
> On Fri, 20 Apr 2012, Markus Metz wrote:
>> g.region res=10m -a

I meant
g.region res=30 -a

with 30 feet roughly equivalent to 10 meter

>> r.resamp.stats in=dem_proj out=dem_10m method=average -w
>  What is the reason to run r.resamp.stats if the region's resolution has
> been changed to that cell size?

The resolution has been decreased, in this case several of the
original cells fall into one new cell. A reasonably accurate new value
can be obtained by using the average of all cells falling into a new
cell. If on the contrary resolution is changed from e.g. 30 to 10 feet
(increased), r.resamp.interp with bilinear or bicubic resampling would
be a good choice.

Markus M

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