[GRASSLIST:3164] Proper input for r.sunmask (GRASS5.3)

GRASS GRASS user
1

Hi all!
I'm trying to use r.sunmask in order to calculate shadowed areas. My DEM's
resolution is 5x5 meters and it has an extension of 4x4 km.
r.sunmask appears to hang at 0% when calculating shadows for DEM(after
having succesfully calculated sun position). Should i be more patient? or is
it something wrong?
Thanks a lot

Javier Yebrin

2

On Wed, Apr 14, 2004 at 03:53:31PM +0200, Javier A. Yebrin wrote:

Hi all!
I'm trying to use r.sunmask in order to calculate shadowed areas. My DEM's
resolution is 5x5 meters and it has an extension of 4x4 km.
r.sunmask appears to hang at 0% when calculating shadows for DEM(after
having succesfully calculated sun position). Should i be more patient? or is
it something wrong?

r.sunmask is just extremely slow.

A trick: use r.sun instead:

http://grass.itc.it/gdp/html_grass5/html/r.sun.html
- use -s flag
- "A map of shadows can be extracted from the solar incidence
    angle map (incidout). Areas with zero values are shadowed."

Hope this helps,

Markus

3

On Wed, Apr 14, 2004 at 03:53:31PM +0200, Javier A. Yebrin wrote:
> Hi all!
> I'm trying to use r.sunmask in order to calculate shadowed
> areas.
> [....]
r.sunmask is just extremely slow.

A trick: use r.sun instead:

Thanks, i'll try that later. I want to see first how does r.sunmask
performs. It's been running for 20 hours and its on 72%.
(Grass53 on AlphaStation 500 - 400Mhz -256 Mb RAM - 1 gb used swap)
Regards.
Javier

http://grass.itc.it/gdp/html_grass5/html/r.sun.html
- use -s flag
- "A map of shadows can be extracted from the solar incidence
    angle map (incidout). Areas with zero values are shadowed."

Hope this helps,

Markus