[GRASS-user] Generalizing SRTM DEM for hillshading

Markus Neteler neteler at itc.it
Tue Jun 20 09:35:25 EDT 2006

On Tue, Jun 20, 2006 at 03:17:43PM +0200, Lars Pennig wrote:
> Dear all,
> I'm trying to generalize the 90m SRTM DEM for use in cartography, e.g. for a hillshading in a 1:700.000 map. Emphasis is on a good-looking map, not on a hydrologic correct model. 
> For this scale, there is too much detail in the SRTM DEM, so I tried different filtering approaches: r.neigbors, r.resample.rst and other methods like resolution-bumping, but the output looks to soft: all the main ridges, which should give a quite crisp image have disappeared. I would like to keep the main structures (like high peaks and long ridges) and drop the small structures like short ridges, small gullys and channels.
> I know, automated generalizing of elevation models is one of the biggest topics in modern cartography, but maybe someone has a good hint :-)
> Thanks in advance, Lars 

Hi Lars,

what about r.contours (use cut= to avoid tiny lines), and then


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