[GRASS-user] Building topologically correct stream network

Hamish hamish_b at yahoo.com
Wed Jul 22 22:35:50 EDT 2009

stephen wrote:
>> Well, I am not sure what I am going to do.  I would look at the
>> code, but I am not adept at C.

none the less, it doesn't hurt to look, depending on how it is written
it might be understandable / tweakable.

> > What exactly is wrong with topology? The existence of these dangles?

note the v.strahler help page makes special mention that if you used
r.watershed you should check the topology. Maybe it makes a bitter deal
out of that than is really the case?

> Maybe there is nothing wrong.  On further reflection the area that
> I am trying to use this procedure on is very flat and there are
> intermittent streams and wetlands (site visit) all over the
> study area.  These non-connected lines maybe showing
> intermittentancy?

do you see a "ladder effect" in the r.to.vect river network?
(like a braided river with all joins at right angles)
maybe that is the problematic topology the module is concerned about?



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