[postgis-users] pgrouting

[Pedro Doria Meunier]

Daniel's solution was completely adequate.
Remember that your vehicle location might not (surely not) be precisely over a 
vertex or line segment. This is the "real life" scenario.

What you must do is create a line segment from the vehicle's location to the 
nearest available vertex and then add the algorithm's result to it (meaning 
to the emergency point)

HTH,

Pedro Doria Meunier
GSM: +351961720188
Skype: pdoriam

On Thursday 11 December 2008 09:50:14 am searchelite wrote:
> Daniel Kastl-2 wrote:
> > As David said: once you selected the nearest vertex to your start, take
> > this vertex ID as your start point (source), and take the nearest vertex
> > ID to your end point as the endpoint (target).
> >
> > Then use Dijkstra for example:
> >
> > SELECT * FROM shortest_path('
> > 		SELECT gid as id,
> > 			 source::integer,
> > 			 target::integer,
> > 			 length::double precision as cost
> > 			FROM ways',
> > 		10, 20, false, false);
> >
> > In this case start point is 10 and end point is 20.
> > See http://pgrouting.postlbs.org/wiki/WorkshopFOSS4G2008/ch07
> >
> > Daniel
>
> Thanks for the reply...
>
> It seems that from your explanation the source and target are the road
> vertex not the actual vehicle point and emergency point(correct me if i'm
> wrong). What i want is to get the path with vehicle_point as the source and
> emergency_point as the target
>
> thank you


-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part.
URL: <http://lists.osgeo.org/pipermail/postgis-users/attachments/20081211/5403675e/attachment.pgp>