r.los

[W. Fredrick Limp]

Though perhaps not what you had in mind ?? you might want
to correspond with C G Laiw and Malcolm Williason at CAST
(cg at cast.uark.edu and malcolm at cast.uark.edu) they developed r.los.not
which creates a map that has the height at each location which,
if added, would allow the location to become visible.  Its
quite useful.
> 
> 
> > >> Does anybody have ideas about the following : we all know
> > >> that r.los can show you the area that is visible from a certain
> > >> observation point, but can it also show you from what area you can observe
> > >> something (I am told that this is not necessarily the same)?
> 
> > Jianping,
> > 
> > I think he's talking about the "one-way visibility" phenomenon that occurs
> > due to geometric interpretation of cells and the algorithms used to determine
> > los, as you demonstrated in your paper this year at the GRASS conference.
> 
> Thank you Bill. So my comment on Philip's message is if you run r.los
> using something as observation point, then there are some area 
> will not be able to see that something even they are "seen" from it.
> The percentage of the "bad" area may vary depending on surface condition,
> among other things.
>  
> > Have you contributed your los program using different alogrithms yet?  Also,
> > have you been able to define under what conditions (resolution vs. height)
> > the one-way visibility is more pronounced?
> > 
> > Bill
> > 
> 
> Not yet. I have a quite tight schedule, and probably do it late this summer.
> 
> Jianping Xu
> 
> 
> 
> 


-- 
W. Fredrick Limp,   Director                     FAX: (501) 575-3846
CAST, Center for Advanced Spatial Technologies   TEL: (501) 575-6159     
12 Ozark Hall, University of Arkansas         
Fayetteville AR 72701                             fred at cast.uark.edu