[GRASS-user] Problem with slope modeling .

[Maciej Sieczka]

Radomir wrote:
> Hi all,
> I'm preparing the slope and elevation map from digitised isolines. 
> I'm using v.surf.rst to do that with the following options:
> 
> v.surf.rst input="izolinie_punkty" layer=1 zcolumn="wysokosc_m_npm"
> dmax=3.174812 dmin=0.634962 elev="mapa_wystaw" slope="mapa_spadk"
> maskmap="maska" zmult=1.0 tension=40. segmax=40 npmin=300
> 
> The screenshot from small part of resulting map is here:
> http://mort.no-ip.org/screen.png
> 
> 
> On this screen you can see the valley in the center. I expect that the
> slope between two isolines on the bottom of the valley will be similar.
> But it is changing and gives an effect of "wave" between isolines.

I had this problem too when interpolating DEM from contour lines with
RST. Try to interploate DEM with r.surf.nnbathy from GRASS WIKI add-ons
page and let us know if the artifact hollow between 2 adjacent contour
lines still remains. I'm not 100% sure it will help. It might.

Maciek