[GRASS-user] Artefacts when interpolating DTM from Contour Lines with v.surf.rst

[Andreas Neumann]

Hello,

I am trying to interpolate a raster DTM from contour lines. I like the
results from v.surf.rst, however, this algorithm, at least with my
settings seams to generate rectangular artefacts in the resulting DTM. See
a hillshade of my result at
http://www.carto.net/neumann/temp/hs_dtm_tension5_smooth2.png - if it
weren't for these artefacts I would like the results very much.

Here are the parameters I used:
v.surf.rst input=hl layer=1 zcolumn=elev_m dmax=10 dmin=0.5
elev=dtm_tension5_smooth2 zmult=1.0 tension=5 smooth=2 segmax=40 npmin=300
--overwrite

The idea is to get a smooth, not too detailed DTM, hence the small tension
and higher smooth values.

Are there any parameters or postprocessing steps that would help me remove
these rectangular artefacts? Or alternatively, are there better methods to
interpolate DTMs from contour lines?

Thanks for any ideas,
Andreas


-- 
Andreas Neumann
Böschacherstrasse 6, CH-8624 Grüt/Gossau, Switzerland
Email: a.neumann at carto.net, Web:
* http://www.carto.net/ (Carto and SVG resources)
* http://www.carto.net/neumann/ (personal page)
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