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.
In *.rst it has to be a set of points along valleys and rigdes - each point
of known elevation. How to obtain such data from a topo map quick and
accurate - I don't know.
nor how to set a different smoothing for points, lines and input data.
5.4 s.surf.rst - smatt
5.7 v.surf.rst - scol
Any idea using only GNU-Linux GPL software?
I'd love to know too if there is something like Catchment SIMGIS or
Topogrid/Anudem on a GPL basis. Has anybody heard of?
Best
Maciek
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
Markus Neteler <neteler@itc.it> wrote:
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.
Great to hear this though I don't understand yet how possible just from your
brief expl. Anyway a friend of mine is going to borrow "A GRASS GIS
Approach" to me soon so then I'll see. Many thanks. Juan - sorry for missinformation.
Maciek