[GRASSLIST:4417] watershed delineation and stream map

[Thomas Dewez]

Dear all,

I looked at the different functions concerning the hydrological analyses
and I am baffled as to which is best suited for my purpose. I'd appreciate
some expert insight on the question.

My aim is to extract several morphotectonic parameters from a 10x10m DEM.
One of the features I am after is the presence of coastal terraces
preserved on valley ridges. To get them out of the DEM I was thinking of
extracting the ridges location (with perhaps a r.watershed command?) then
process each individual ridge profile looking for flat surfaces (perhaps
with a histogram of elevation of the ridge?). That's for the principle but
I am not sure how to implement this efficiently.

The r.watershed interactive module requires the manual input of the pour
point coordinates before it can run (is this correct?). Well, I'd rather
not have to input those manually and have an algorithm do it for me.
That's perhaps a little lazy but surely it exists. Does anybody have a
suggestion about this question?

Thanks for your help

Thomas