Tyler Smith wrote: >> I'm having some trouble with r.horizon. ... >> I'm preparing maps for use in r.sun, ... Also, in case you didn't read already, check-out <http://grasswiki.osgeo.org/wiki/R.sun> (and, perhaps details in this bug ticket: <https://trac.osgeo.org/grass/ticket/498> -- there might be interesting details). Nikos