[GRASSLIST:5123] Re: adding stream axis to dem

[Markus Neteler]

On Fri, Dec 10, 2004 at 06:15:34PM +0100, Maciek Sieczka wrote:
> >Thank you, Maciek. I have this article for time and it is well-read often.
> >What it proposes is exactly what I want to do, but the article doesn't say
> >anything about how to incorporate the skeleton of valleys and ridges
> 
> You can't simply input vector lines indicating valleys and ridges for *.rst
> modules (nor for other interpolation modules in Grass, such a shame). But
> you can do it in e.g. Catchment SIMGIS.

You can do it, with s/v.surf.rst.

Briefly: first interpolate without valleys (or gullies for gully erosion),
then interpolate with valleys. Then use r.mapcalc to merge both maps.
The trick is to use the "mask" parameter of s.surf.rst.

The tha manual page and/or see our book:
 Open Source GIS: A GRASS GIS Approach, chapter 7.3.5 in
 the 2nd edition 2004.
 http://mpa.itc.it/grassbook2/

Best

 Markus