Quick question: is there a functional difference between the shadow algorithm found in r.sun and r.sunmask? I'd like to use a ray-trace based shadowing algorithm -- if r.sunmask does this (the documentation doesn't indicate whether or not it does), it seems that would be a faster alternative to running the entire r.sun algorithm.
--j
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Jonathan A. Greenberg, PhD
Postdoctoral Scholar
Center for Spatial Technologies and Remote Sensing (CSTARS)
University of California, Davis
One Shields Avenue
The Barn, Room 250N
Davis, CA 95616
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AIM: jgrn307, MSN: jgrn307@hotmail.com, Gchat: jgrn307
On Jan 9, 2008 12:28 AM, Jonathan Greenberg <greenberg@ucdavis.edu> wrote:
Quick question: is there a functional difference between the shadow
algorithm found in r.sun and r.sunmask?
Yes.
I'd like to use a ray-trace
based shadowing algorithm -- if r.sunmask does this (the documentation
doesn't indicate whether or not it does), it seems that would be a
faster alternative to running the entire r.sun algorithm.
r.sunmask is WAY slower.
r.sun -s is fast and includes also earth curvature.
Additionally, we have r.horizon/r.sun2 which might be of interest:
http://trac.osgeo.org/grass/browser/grass-addons/r.sun_horizon
I assume that r.sun2 is again faster since r.horizon was separated
out and needs to be run only one time.
Markus