On Mon, May 18, 2015 at 4:47 PM, Irantzu Alvarez <irantzu.alva...@gmail.com> wrote: > > I am trying to create a DEM from a bathymetric contour lines.
To replicate, I have downloaded a bathymetric DEM portion from http://www.marine-geo.org/tools/maps_grids.php (downloaded as GeoTIFF, LatLong, imported with r.in.gdal). I am using GRASS GIS 7.0.svn here. > Contours are > in vector format and the elevation value is negative (integers). ok, in my test case I have run r.contour GMRTv2_7_bathy_mediterranean step=100 min=-4000 max=3500 output=GMRTv2_7_bathy_mediterranean_contours_100m > To create > the surface I have converted the contours in raster (v.to rast) Yes: v.to.rast input=GMRTv2_7_bathy_mediterranean_contours_100m output=GMRTv2_7_bathy_mediterranean_contours_100m use=attr attribute_column=level > and then I > have used r.surf.contour, but It doesn't work (there is no error but the > resulting output raster is exactly the same as the previous one, without any > interpolation). Strange. Here, with r.surf.contour input=GMRTv2_7_bathy_mediterranean_contours_100m output=GMRTv2_7_bathy_mediterranean_interpol ... I got back a nice bathymetric DEM (naturally, the "differences" map generated with r.mapcalc shows some differences to the original map I derived the contour lines from given the oversimplification done with the vectorization). > This are my region settings: > > g.region -p -a raster=contours@iiaa nsres=1 ewres=1 > projection: 1 (UTM) > zone: 30 ... > rows: 27443 > cols: 114763 > cells: 3149441009 Which GRASS GIS version are you using? > I need a DEM of very high resolution of a wide area. I am using a computer > with large capacities for it. Yes, but which operating system? My full procedure below. HTH, Markus -- http://consulting.neteler.org http://courses.neteler.org/next-training/ http://gis.cri.fmach.it/neteler/ ######## Test case procedure (GRASS GIS 7) # import bathymetric map, downloaded from http://www.marine-geo.org/tools/maps_grids.php r.in.gdal /home/neteler/data/GMRTv2_7_20150525topo.tif out=GMRTv2_7_bathy_mediterranean -o g.region raster=GMRTv2_7_bathy_mediterranean r.colors GMRTv2_7_bathy_mediterranean color=srtm_plus # visualize imported map d.mon wx0 d.rast GMRTv2_7_bathy_mediterranean # generate contour lines (for our test case) r.info GMRTv2_7_bathy_mediterranean r.contour GMRTv2_7_bathy_mediterranean step=100 min=-4000 max=3500 output=GMRTv2_7_bathy_mediterranean_contours_100m d.vect GMRTv2_7_bathy_mediterranean_contours_100m # rasterize contour lines v.to.rast input=GMRTv2_7_bathy_mediterranean_contours_100m output=GMRTv2_7_bathy_mediterranean_contours_100m use=attr attribute_column=level # visualize colorized contour lines d.mon wx1 r.colors GMRTv2_7_bathy_mediterranean_contours_100m color=srtm_plus d.rast GMRTv2_7_bathy_mediterranean_contours_100m # interpolate DEM from contour lines r.surf.contour input=GMRTv2_7_bathy_mediterranean_contours_100m output=GMRTv2_7_bathy_mediterranean_interpol r.colors GMRTv2_7_bathy_mediterranean_interpol color=srtm_plus r.info GMRTv2_7_bathy_mediterranean_interpol # visualize new resulting map d.mon wx2 d.rast GMRTv2_7_bathy_mediterranean_interpol # generate differences map for validation r.mapcalc "GMRTv2_7_bathy_mediterranean_diff = GMRTv2_7_bathy_mediterranean - GMRTv2_7_bathy_mediterranean_interpol" r.colors GMRTv2_7_bathy_mediterranean_diff color=differences # visualize differences map d.mon wx3 d.rast GMRTv2_7_bathy_mediterranean_diff # optionally generate histogram or profiles via wxGUI
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