[GRASS-user] shortest distance between 2 segments?

[Michael Barton]

V.distance?

Michae
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton



> From: A Horacio Samaniego <horacio at unm.edu>
> Date: Tue, 20 Jun 2006 16:27:07 -0600 (MDT)
> To: <grassuser at grass.itc.it>
> Subject: [GRASS-user] shortest distance between 2 segments?
> 
> I have a question on the network functionality on GRASS
> 
> Is there any way to query the shortest path between two vector segments in
> GRASS?
> 
> I have the following 2 segments in the DB
> 
> [local] roads=# select
> cat,fename,fetype,fraddl,fraddr,toaddl,toaddr,road_type from
> nm_bernalillo_alb where cat=18607 OR cat=12697;
>    cat  | fename  | fetype | fraddl | fraddr | toaddl | toaddr | road_type
> 
---------+------------+--------+--------+--------+--------+--------+---------->
-
> 12697 | Amherst | Dr       | 901    | 900    | 1013  | 1016  |      8
> 18607 | Monroe  | St        | 901    | 900    | 999    | 998    |       8
> (2 rows)
> 
> 
> I get the following output with no results because I believe you are
> required to specify points :
> 
> GRASS 6.0.0 (albers):~ > echo "1 18607 12697" | v.net.path
> input=nm_bernalillo_alb output=path2 afcolumn=road_type
> Building graph:
> Registering arcs ...  100%
> Flattening the graph ... done.
> Graph was built.
> WARNING: No point with category 18607
> WARNING: No point with category 12697
> Attributes:
>    cat  - path unique category assigned by module
>    id   - path id (read from input)
>    fcat - from point category
>    tcat - to point category
>    sp - result status:
>         0 - OK, path found
>         1 - node is not reachable
>         2 - point of given category does not exist
>    cost - travelling costs (on the network, not to/from network)
>    fdist - the distance from first point to the network
>    tdist - the distance from the network to second point
> WARNING: 2 points of given category missing
> Building topology ...
> 0 primitives registered
> 0 areas built
> 0 isles built
> Attaching islands:
> Attaching centroids: Topology was built.
> Number of nodes     :   0
> Number of primitives:   0
> Number of points    :   0
> Number of lines     :   0
> Number of boundaries:   0
> Number of centroids :   0
> Number of areas     :   0
> Number of isles     :   0
> 
> 
> thanks!
> 
> H
> 
> Horacio Samaniego
> Department of Biology
> University of New Mexico
> Albuquerque, NM. 87131
> Phone:  (505) 277-3431
> Fax:    (505) 277-0304
> 
> (http://www.unm.edu/~horacio)
> 
>