Johannes Radinger <[email protected]> writes: > Hi, > > what is the most effective way to assign randomly > the values -1,0 and 1 to a raster map, where each of > the three values should occur in one third of the map. > > Furthermore I'd like to assign to 10 % of the cell > the values -1 and 10% the value 1 and to the remaining > 80% the value 0 (or any other arbitrary combination of
EXACTLY 10%, or with a probability of 10? If EXACTLY, I guess you have to use different functions (select 10% random cells, assign -1, mask them out, select again 10% of the ORIGINAL NUMBER of cells, assigh=n 1, assgn 0 to the rest) Otherwise, you can use the random() function in r.mapcalc: r < 0.1 -> assign 1 r > 0.9 -> assign -1 otherwise assign 0 Hope this helps, Rainer > the three values). Is there any fast way in G7 or do I need > to play with r.random, r.mask and r.mapcalc and r.patch. > > Maybe someone has already had such a task... > so any suggestion is welcome. > > cheers, > Johannes > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user <#secure method=pgpmime mode=sign> -- Rainer M. Krug email: RMKrug<at>gmail<dot>com _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
