r.sun.daily computing time optimization

[saudeoud]

Hello all,

I am trying to use r.sun.daily to calculate sun hours for every season, for agricultural purposes.

I am working on a 100 km² area on with a DEM of 5m res, so the computing is quite long. I am searching for info about the sensitivity of the parameters of r.sun, r.sun.daily and r.horizon (+ DEM resolution) and global r.sun.daily rational process.

Actually I need this data for only 3km² of the total area. I thought about using r.mask but I guess the mask will also... mask many of the the elevation data to r.sun. Obviously I want r.sun to calculate only for certain areas but "seeing" all surroundings elevation data.

I actually have no idea of the behavior of the modules in this case, i.e. is the mask handled in a "smart" way ?

Maybe using r.horizon with mask and then r.sun.daily with no mask but masked horizon maps will do the job ?

Interested by all comments.

Thanks,

Samuel Audéoud