Hi all,
Does anybody know how to perform a cost-distance analysis? I'm planning a
street and have assigned various costs to different surfaces in my planning
area. As I understand it, I need to perform the following steps:
1. r.cost using the starting point to generate a cost map for each pixel
2. r.walk to generate a raster with cumulative movement costs for each pixel
from the point of origin
3. r.drain to generate the road
My problem is, I don't want to model drainage; I want to find the route with
the lowest costs possible to connect two points. Is there a way to calculate
the path of least resistance from my origin point to a goal point? I've
thought of using r.cost with two different points and then performing
r.drain to connect the two. But would that work? It seems like r.drain
produces paths that end at the point with the lowest cost, but that's not my
goal - it gives me no control over where the street ends.
Thanks a bunch for the help!
Daniel
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LeeDaniel wrote:
Hi all,
Does anybody know how to perform a cost-distance analysis? I'm planning a
street and have assigned various costs to different surfaces in my planning
area. As I understand it, I need to perform the following steps:
1. r.cost using the starting point to generate a cost map for each pixel
2. r.walk to generate a raster with cumulative movement costs for each pixel
from the point of origin
3. r.drain to generate the road
My problem is, I don't want to model drainage; I want to find the route with
the lowest costs possible to connect two points. Is there a way to calculate
the path of least resistance from my origin point to a goal point? I've
thought of using r.cost with two different points and then performing
r.drain to connect the two. But would that work?
No, use either your origin point or your goal point as start point for
r.cost but not both points as start points, then use the other point
as start point for r.drain. You could also use either the origin point
or the goal point as start point for r.cost and the other point as
stop point for r.cost to speed up r.cost
It seems like r.drain
produces paths that end at the point with the lowest cost, but that's not my
goal - it gives me no control over where the street ends.
You do have control over where the street ends, if you use only one
start point for r.cost, because this will be the point with the lowest
cost. If I understand correctly, r.drain will then always stop at the
point used as start point for r.cost.
HTH,
Markus M