Hi Clemens, To smooth dems, use the following:
Install http://www.saga-gis.org/en/index.html saga gis & install the sextante plugin. Under the Analysis menu, open the Sextante options & configuration, click on saga. Sextante should find your install of saga (I'm assuming a windows platform here) at something like c:/program files/saga-gis/. Ensure the "use min covering grid system for resampling" is checked. Click Analysis menu -- Sextante Toolbar. This opens the toolbox, you can type filter in the text search. Alternatively, just expand saga -- grid filter, you will have ~ 10 filter choices. Not sure of the filtering application (cartographic or analytical) you can employ the "simple" filter with its default smooth using 11*11 for ~ 990m output. If maintaining slopes are important, review the multi-directional filter as it implements a lee based filter. I'm pretty sure the input raster must be tif. #----- Moving the srtm 90m? to 1km resolution is resampling the dataset. You can use the built in gdal tools-- http://www.gdal.org/gdalwarp.html warp dialog for this. In the dialog after you have entered the information click the pencil to allow editing of the config text, add the following argument (before the -r method) to allow resample to 1km -tr 1000 1000. Ensure resample method is not near but bicubic. #----- You can empose spatial scale on your orginial srtm90m by filtering with a large filter say 11*11 (~990m support area) but the dem posting will remain 90m. This avoids resampling & may be a better way forward, I've used the aforementioned approach for some soil tools. Cheers, Richard -- View this message in context: http://osgeo-org.1560.n6.nabble.com/Smooth-DEMs-tp4987519p4987640.html Sent from the Quantum GIS - User mailing list archive at Nabble.com. _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user