[GRASS-user] r.watershed: Problems Using

[Rich Shepard]

On Wed, 10 Feb 2010, Jarek Jasiewicz wrote:

> not so large, I'd rather say moderate

Jarek,

   I have larger maps.

>>   OK. Please explain 'exterior watershed basin' in the context of
>> r.watershed.
> it is the size (in cells number) of flow accumulation when r.watershed starts 
> delineate streams

   OK. Because I have a vector map of drainage basins I was thinking exterior
to the basin of interest. Now I know better. Thank you.

   Now this is interesting: The basin of interest covers about 9,550 ha. When
I try running r.watershed with the DEM resolution of 5m it keeps failing.
However, running the module on the 10m resolution DEM is working. There's
still 18G of free space on that partition; could the temporary file be
greater than that?

   For a drainage basin of 9,550 ha, would there be meaningful differences in
r.watershed output between 10m and 5m cell size?

Thanks,

Rich