[GRASS-user] r.sun for selected points

[Vaclav Petras]

On Wed, Aug 13, 2014 at 4:46 PM, Tyler Smith <tyler at plantarum.ca> wrote:

> I'm trying to generate solar irradiance data for a set of points (which
> requires r.horizon and r.sun output). My data covers most of eastern
> North America at 20m by 20m resolution. This is beyond the capacity of
> my computer to process. However, I don't need complete maps for this
> area. I only need the beam values for ca. 10,000 point locations. I
> expect it would be possible to do this on my laptop, but I can't figure
> out how to limit the analysis to these spots. Is it possible? Does
> anyone have any suggestions?
>

I'm not sure if I see all the details but if you can script in Python or
Bash you can do something like iteration over all points using PyGRASS or
v.out.ascii and textual processing (the later applies also for external
files with points) and then set computation region using g.region around
each point to sufficient extent. Then you compute the r.horizon and r.sun
just in the specified (computational) region and store the results as maps
and as text (using e.g. r.univar or v.what.rast). Does this make sense?
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