Hi,
I'm just wondering what the v.net.path module uses to determine the
default cost of an arc. It doesn't seem to be distance as this is the
shortest path it gave me between 2 nodes:
http://www.cs.utah.edu/~ryant/shortestpath.gif
Also, as some background information, this is what i've done to generate
the shortest path. I started with some vector data called "slc" which
contains real road data, then I ran a v.net to generate a vector map
called "nodesmap" with the node data. then i did a v.category with
"nodesmap" as the input and "categorymap" as
the output. Finally I did a v.net.path with "categorymap" as input and
"shortestpath" as the output--which you can see in red in the gif file.
Ultimately I'm trying to determine a shortest path between two points that
takes into account more than distance. My original vector data set
contains columns that describe speed limits, road directions, road
quality, etc. How could I get v.net.path to take several fields like that
into account? Also, since I'm generating the "shortestpath" vector map
from "categorymap" and not from my original dataset "slc", how can I
specify to v.net.path to take into account values from "slc"?
Thanks for any help you can give me. I really appreciate it.
Ryan T.
Ryan D Taylor wrote:
Hi,
I'm just wondering what the v.net.path module uses to determine the default cost of an arc. It doesn't seem to be distance as this is the shortest path it gave me between 2 nodes:
http://www.cs.utah.edu/~ryant/shortestpath.gif
Are you sure that there are no gaps in the network? Is it TIGER?
Try to test with d.path and v.digit if the lines are connected.
Also, as some background information, this is what i've done to generate the shortest path. I started with some vector data called "slc" which contains real road data, then I ran a v.net to generate a vector map called "nodesmap" with the node data. then i did a v.category with "nodesmap" as the input and "categorymap" as the output. Finally I did a v.net.path with "categorymap" as input and "shortestpath" as the output--which you can see in red in the gif file.
Ultimately I'm trying to determine a shortest path between two points that takes into account more than distance. My original vector data set contains columns that describe speed limits, road directions, road quality, etc. How could I get v.net.path to take several fields like that into account? Also, since I'm generating the "shortestpath" vector map from "categorymap" and not from my original dataset "slc", how can I specify to v.net.path to take into account values from "slc"?
You have to calculate costs in one column and then use afcolumn, abcolumn, ncolumn.
Radim
Thanks for any help you can give me. I really appreciate it.
Ryan T.
