s.surf.tps

[mike at ce.umanitoba.ca]

> Hello!
> 
>       I want to built a DEM using s.surf.tps from a contour lines map
> and some reference heights I digitized before. The result of this process 
> is quite nice ussually. But my problem now is that I'm working in a very 
> flat area. The contour interval in the maps I vectorized was of 10 metres.
> So, in the flatest zone I may have more than 1 square kilometre without
> any data. I thought I could improve the DEM if I could use streams and
> rivers as topographic data, I mean forcing s.surf.tps to consider that
> stream cells are in lower heights than their neighbors.
>       Is this possible in s.surf.tps?
>       Is this possible in any other interpolation algorithm in Grass?
> 
> 
>                               Xavier Ros
>                       Unitat de Geodinamica Externa i d'Hidrogeologia
>                       Universitat Autonoma Barcelona
>                       e-mail: xavi at cataw.uab.es
> 

Xavier,

I didn't notice if anybody has responded to your notice.  Hopefully this will h
elp.

I have been through the same thing with flat areas.  I did not like the results
 from s.surf.tps.  I think s.surf.contour will do a good job for you, especiall
y since your area is flat.  The only problem is that it may take a very long ti
me to run since there are large open areas with no data.  Any additional elevat
ion information you can give it would be beneficial.

__________________________________________________________________
Mike Bender
Facility for Intelligent Decision Support in Water Resources
Civil & Geological Engineering
University of Manitoba
Winnipeg, Manitoba, R3T 2N2, CANADA

(204) 474-6746 [phone]
(204) 261-9534 [fax]

mike at fids.ce.umanitoba.ca