[GRASS-user] r.horizon problems with large DEM

[Markus Neteler]

On Mon, Nov 23, 2009 at 8:05 PM, Joshua Campbell
<jcampbell.geo at gmail.com> wrote:
> I have been trying to run r.horizon on a SRTM DEM for the continental US,
> with no success. The operation runs for about 45 minutes then eventually
> just stops with no warnings or errors
>
> I'm running GRASS 6.4-rc5 64-bit in Ubuntu 9.10 on a virtual machine
> (Virtual Box on Windows XP 64-bit).
>
> The r.horizon function will consume as much RAM as apply to the machine, up
> to 6144 MB, plus an additional 4GB of swap memory.
>
> The DEM is in Geographic coordinates - WGS 84. I tried to run r.horizon in
> only 1 direction with maximum distance of 5310 meters.
>
> Is there a file size limitation? Or any suggestions for an optimal size?

Do you really want r.horizon or do you want it as input for r.sun?
If so, see also here:
http://grass.osgeo.org/wiki/Rsun

I recently used r.sun without r.horizon and it took way less RAM.

Markus