Jon wrote: > I would like to calculate the average slope by square kilometer > for a giving area. I have a raster of the considere area with > the altitude. So my plan is to create a grid of square of 1 km² > and to calculate for each square the average slope. > > My main problem is that I don"t have any idea how to make > it with grass.
- make a slope map from the DEM with r.slope.aspect at the same resolution and bounds as the DEM. (run 'g.region rast=dem' first) - make the grid with v.mkgrid, with box=1000,1000 (assuming the location is meters-based) - draw a 1 km x 1 km grid (d.grid), and overlay the v.mkgrid vector map (area fill = none, or only display boundary features, colored red or so) just to verify where it will be and what it will look like. - run v.rast.stats to calculate stats for each grid box, and upload to that area's attribute table. > Could someone give some tips? > I put the raster i use at the following adress: > http://www.megaupload.com/?d=IWRZC0HH Hamish _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
