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

[Andrea Ricci]

Andreas Neumann wrote:
> 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
>
>
>   
Try with increasing dmin= 2 or try with other values. Normally, in case  
of visible segmentation, this value must be increased.
hope that's helpful
Andrea Ricci