[GRASS-user] Re: understanding r.watershed
markus.metz.giswork at googlemail.com
Mon Feb 2 13:31:06 EST 2009
Georg Kaspar wrote:
> ok, so I only need to specify depressions that do not loose water!?
> Artificial depressions like postholes or pits for example!?
Rather something with a few hectares in size (at least), e.g. water
reservoirs where water is pumped out, no overground outflow. Postholes
and small pits are not able to distort r.watershed. The best example for
a real depression is the Dead Sea, a big lake with no outflow.
> What would be
> the difference between purging the DEM from those depressions and
> providing them as binary input for r.watershed?
Generally there is no need to purge the input DEM from depressions, why
do you insist on doing so?
The difference between purging a DEM and providing an option
depression=<map with real depressions> has been explained before in this
thread , .
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