On Sat, Jan 4, 2014 at 12:17 PM, Tim Michelsen <timmichel...@gmx-topmail.de> wrote: ... > Perhaps r.sun.hourly should get ... > * average sunlight duration per day during a month, etc. (h/d)
This needs some modifications in the r.sun code. I was discussing this issue some time ago with Jaro Hofierka who gave the following hints: On Thu, Apr 16, 2009 at 18:34, Jaro Hofierka <hofie...@geomodel.sk> wrote: > Markus, > > sunrise, sunset times are calculated for each cell, however, not including > shadows by surrounding terrain features. This would need another test which > in fact is done during radiation calculations (there is a time step to sum > up radiation), but the time is not stored. > To minimize a number of output maps we have stored the information of > sunrise/sunset times using min-max values in a history file (or a single > value when a single value of latitude is used for the map). So it would need > a modification of the code to put there extra files storing sunrise-sunset > times. If you need a quicker solution, you would need to make tests just for > a small part of the day (e.g. 1-2 hours around reported sunrise/sunset > times). > > Jaro Perhaps useful as a pointer. Markus _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user