[GRASS-user] r.sun for selected points

[Nikos Alexandris]

Tyler Smith:

>> > but I can't figure out how to limit the analysis to these spots.
>> > Is it possible? Does anyone have any suggestions?

roy:

>> you sure can use the region settings and the r.mask GRASS module to
>> limit the analysis area: use "g.region" and "r.mask"

Tyler:

> I've tried this. However, the spread of my points covers most of the
> area involved. So I can't reduce the total area very much, especially
> when I need to keep a buffer around the points for r.horizon. What 
> I'm
> looking for is a way to tell GRASS to calculate r.horizon values only
> for a list of points, rather than an area. And for the second step, 
> to
> calculate r.sun beam values using the same points.

Questions and ideas that might help:

How dense is your point data-set?  What is the spatial resolution your 
aiming at?  Could latitude be your criterion in eliminating (somehow) 
points?  It's an important factor in estimating solar irradiation.  
Maybe take ideas from existing maps (10km seems to be a high resolution 
value for solar irradiance mapping).

Nikos