I need to create a plan for a new road from a known source point, to a known destination area. I have a grid of elevation and land use for the region. So from that I can calculate a cost weight using r.walk or r.cost Now by using this I'd like to calculate a new raster or vector which would show the least cost path from source to destination.
Is this possible? I know that with Arc/Info I can use the Spatial Analyst to do this, but I'd like to be able to do it with GRASS. Any ideas?
On Friday 26 January 2007 03:12, Wolf Bergenheim wrote:
Hi!
I need to create a plan for a new road from a known source point, to a
known destination area. I have a grid of elevation and land use for the
region. So from that I can calculate a cost weight using r.walk or
r.cost Now by using this I'd like to calculate a new raster or vector
which would show the least cost path from source to destination.
Is this possible? I know that with Arc/Info I can use the Spatial
Analyst to do this, but I'd like to be able to do it with GRASS. Any ideas?
--Wolf
Hi Wolf,
The usual approach in GRASS for this type of problem is:
1. define cost surface (slope is commonly used) but a distance map would work
as well (r.mapcalc "dist = 1")
2. create cumulative cost map (r.cost) along with the cost surface from step 1
3. simulate a drop of water 'draining' from some destination to the point of
least cost (your starting point) (r.drain)
4. use r.to.vect to vectorize the output from r.drain.
Use r.drain with your cost surface (made from the destination point) and the
source point.
Michael
On 1/26/07 4:12 AM, "Wolf Bergenheim" <wolf+grass@bergenheim.net> wrote:
Hi!
I need to create a plan for a new road from a known source point, to a
known destination area. I have a grid of elevation and land use for the
region. So from that I can calculate a cost weight using r.walk or
r.cost Now by using this I'd like to calculate a new raster or vector
which would show the least cost path from source to destination.
Is this possible? I know that with Arc/Info I can use the Spatial
Analyst to do this, but I'd like to be able to do it with GRASS. Any ideas?
--Wolf
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University
Wolf Bergenheim wrote:
> I need to create a plan for a new road from a known source point, to
> a known destination area. I have a grid of elevation and land use
> for the region.
Dylan Beaudette wrote:
The usual approach in GRASS for this type of problem is:
1. define cost surface (slope is commonly used) but a distance map
would work as well (r.mapcalc "dist = 1")
2. create cumulative cost map (r.cost) along with the cost surface
from step 1
3. simulate a drop of water 'draining' from some destination to the
point of least cost (your starting point) (r.drain)
4. use r.to.vect to vectorize the output from r.drain.