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
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
v.surf.rst?
Markus
On Tue, 20 Jun 2006 15:35:25 +0200
Markus Neteler <neteler@itc.it> wrote:
what about r.contours (use cut= to avoid tiny lines), and then
v.surf.rst?
For a predictable DEM from contours, I'd recommend r.surf.nnbathy (see
WIKI).
Maciek
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On 6/21/06, maning sambale <emmanuel.sambale@gmail.com> wrote:
I tried making a script creating a multidirectional, oblique-weighted,
shaded-relief image from an input DEM image. Might be useful.
link:
http://esambale.wikispaces.com/hillshade+multi
Maning
On 6/21/06, Maciek Sieczka <werchowyna@epf.pl> wrote:
> On Tue, 20 Jun 2006 15:35:25 +0200
> Markus Neteler <neteler@itc.it> wrote:
>
> > what about r.contours (use cut= to avoid tiny lines), and then
> > v.surf.rst?
>
> For a predictable DEM from contours, I'd recommend r.surf.nnbathy (see
> WIKI).
>
> Maciek
>
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