Hi, 2011/3/13 Giovanni Manghi <giovanni.manghi at gmail.com>: > r.los it's quite slow, you can try also r.viewshed from addons [1]. Martin [1] http://grass.osgeo.org/wiki/GRASS_AddOns#r.viewshed -- Martin Landa <landa.martin gmail.com> * http://geo.fsv.cvut.cz/~landa