[gdal-dev] Converting contour lines (Shape files) into DEM

Frank Warmerdam warmerdam at pobox.com
Tue Mar 30 08:12:20 EDT 2010

Jan Hartmann wrote:
> Frank, is there a description of the way the smoothing is done, or 
> should I look it up in the code?


It does a user defined number of iterations of 3x3 average filtering,
only altering the interpolated pixels.   The algorithm discussion,
such as it is, is attached to the API function:


> BTW: there is a description of the algorithm used in GRASS to create 
> contour lines:
> https://trac.osgeo.org/grass/browser/grass/trunk/raster/r.contour/README
> This looks much more adapted to the specific case of contour lines than 
> the general weighted distance model in GDAL (which is the best one for 
> general purposes IMHO). Would it make sense/be possible to adapt the 
> GRASS code for GDAL? Doesn't look all too difficult to me.
st regards,

My reading of r.contour is that it creates contours from a raster, the
process equivelent to what gdal_contour does, not gdal_rasterize + gdal_fillnodata.

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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