[GRASSLIST:2143] Re: curvature scripts?

[Tom Poindexter]

On Mon, Jul 23, 2001 at 05:37:24PM +0930, Gail Higginbottom wrote:
> Do you know of anyone who has written a script for Grass that allows us to
> incorporate the curvature of the earth when we use the r.los or other
> forms of assessment?


Sorry, I don't know of a GRASS program such an analysis.  I for one, would
also like to see a 'better' LOS analysis program, but I haven't had the
time to write one either.  r.los seems to be a real pig on large
areas also.  One possible soultion would be a r.mapcalc script to
create a new raster that artifically drops the evelation of cells the
farther from some designated analysis point.  

One piece of software that I have used for LOS analysis is at:
	http://www.mindspring.com/~otterson/cs485/index.html

Note that this software assumes a 'K Factor' of 1.3, ie. the atmoshperic
effects on VHF/UHF radio propagation, resulting in a flatter earth.
Of course that can easily be changed in the source.  

-- 
Tom Poindexter
tpoindex at nyx.net
http://www.nyx.net/~tpoindex/