[GRASS-user] Creating a ground water from a vector files of contours?

[Dylan Beaudette]

On Monday 05 February 2007 23:13, Hamish wrote:
> Dylan Beaudette wrote:
> > > Bob wrote:
> > > > Like the subject line says, I need help creating a ground water
> > > > map using a vector file of contours.  The ground water file came
> > > > from a E00 file that was read into Grass using v.in.e00.  I am
> > > > currently running v.surf.rst which is taking a long time to run.
> > > > Are there other ways to do this problem?
>
> H:
> > > r.surf.contour - Surface generation program from rasterized
> > > contours.
>
> Dylan:
> > not sure how well this would work, but ...
>
> (r.surf.contour does work well!, also try r.surf.nnbathy from wiki addons)

Oops, looks like I commented without reading. I meant to say that gridding 
from contour data can be problematic as compared to a pile of points. 

> Dylan:
> > how about
> >
> > v.to.points
> > transfer elevation from contour lines to point [z] coordinates
> > v.surf.rst or other interpolator...
>
> that doesn't work very well as it aliases results at areas of high point
> density. (ie along the contour lines)

Good point.

> Imagine what the quadtree segmentation vector looks like in that case.
> (v.surf.rst treefile=)
>

will have to try that some time...

Cheers,

-- 
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341