>>António Rocha: >>Hi there >>I need to randomly select non-null cells from a given map. I tried >>r.random.cells but I cannot define a maximum number random cells and >>some selected random cells are not valid values in my map. is there any >>other function to randomly select cells from a raster?
Hello Antônio, This one I think I can help. There is this command "v.random" that allows you to create a vector containing random points in your current region. And you can control the number of points with the parameter "n". Than you can upload the vector database with values from any raster with the command "v.what.rast" and than export it to a file if you want. The manual has this clarifying example: v.random output=random_samples n=20 v.db.addtable map=random_samples layer=1 columns='cat INTEGER, sample DOUBLE PRECISION' v.what.rast vector=random_samples raster=elevation....@permanent layer=1 column=sample However, I believe that if you have null cells in your raster and some of the random points happen to fall over them, you will have less valid points than you expect, so I would say that you should check the resultant database. Hope this helps. Best regards, Marcello. -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/Select-random-cells-from-map-tp5125298p5125703.html Sent from the Grass - Users mailing list archive at Nabble.com. _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
