[GRASS-user] Using r.los to find where an object could be hidden

[Markus Metz]

On Fri, Oct 7, 2011 at 7:49 AM, Josh Doe <josh at joshdoe.com> wrote:
> I've just used r.los for the first time, but want to do something
> slightly different this time. Instead of finding what points
> on-the-ground are visible by the observer, I want to find what points
> at a height above-the-ground are visible by the observer. Or the
> inverse, given a height of an object (person, tree, whatever), what
> areas could hide these objects. I'm guessing I can't make r.los do
> what I want without modifying the code.
>
> Just to be clear, the results I'm looking for will indicate a spot is
> visible even behind a hill, so long as the object height is
> sufficiently large enough to appear above the top of the hill.
>
> Does anyone know of a trick to do what I want, or perhaps have done
> something similar and can share a script?
>
r.viewshed in the grass-addons can do exactly that what you want.

Markus M