[GRASS-user] intersection of network-lines and areas

[Markus Metz]

achim wrote:
> ...but how can I query my raster-streams in r.water.outlet? I cannot
> write in all points manually. Do I have to write a script for that?
>   
You can query the raster streams in the GUI map display, then cut and 
paste the coordinates to r.water.outlet as easting and northing.
I'm not sure I understood your question correctly, clarification from my 
side: for each river network you need only one point/set of coordinates 
in r.water.outlet, namely the outlet point.

Regarding your other post, only one cell as output: this would happen if 
the outlet point specified for r.water.outlet is not exactly on the 
stream, but one cell (or more cells) off.

Going back to the vector approach, maybe v.overlay can help.