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?
On Fri, Oct 7, 2011 at 7:49 AM, Josh Doe <josh@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.
On Fri, Oct 7, 2011 at 2:28 AM, Markus Metz
<markus.metz.giswork@googlemail.com> wrote:
On Fri, Oct 7, 2011 at 7:49 AM, Josh Doe <josh@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.
Indeed, it looks to fit the bill perfectly, thanks! The only trouble
now is getting it compiled. I'm on Windows XP, and it seems the
Makefile doesn't work out of the box. I also tried g.extension, but it
complains of SVN missing, though I'm not sure what svn client it needs
(I've got a Cygwin svn.exe, but adding my Cygwin bin to the path
doesn't seem to help matters).
Hopefully I'll get it working soon, thanks for the reference.
Indeed, it looks to fit the bill perfectly, thanks! The only trouble
now is getting it compiled. I'm on Windows XP, and it seems the
Makefile doesn't work out of the box.
I also tried g.extension, but it
complains of SVN missing, though I'm not sure what svn client it needs
(I've got a Cygwin svn.exe, but adding my Cygwin bin to the path
doesn't seem to help matters).
g.extension isn't working at the moment in wingrass.
On Sun, Oct 9, 2011 at 6:20 AM, Helmut Kudrnovsky <hellik@web.de> wrote:
hi,
Indeed, it looks to fit the bill perfectly, thanks! The only trouble
now is getting it compiled. I'm on Windows XP, and it seems the
Makefile doesn't work out of the box.
Great, that download works perfectly, thanks for packaging this up!
I also tried g.extension, but it
complains of SVN missing, though I'm not sure what svn client it needs
(I've got a Cygwin svn.exe, but adding my Cygwin bin to the path
doesn't seem to help matters).
g.extension isn't working at the moment in wingrass.
I see; at least I don't need it for now thanks to your packaging with
the add-ons.