[Cartoweb-users] Questions about about pgdijkstra

Fay Du fay.du at versaterm.com
Tue Jan 17 15:21:45 EST 2006

Oops, Sorry again, click reply without looking again. Now I send email
to the list. 
Sorry, I don't mean sent my email to you. I just clicked reply button
and somehow it went to you directly. I thought it went to list. I will
double check to address before click send button.
For the question, I got the answerer by match shortest pass with
original data. Actually, although shortest_pass does not use geometry
directly, but when we call create_graph_tables, the function reads
source from start point, and reads target from end point. So, Pgdijsktra
still follow edge graph direction to create shortest path. If an edge
start point is A and end point is B, if we set directed=ture, the
shortest cannot go from B to A.
-----Original Message-----
From: Sylvain Pasche [mailto:sylvain.pasche at camptocamp.com] 
Sent: Tuesday, January 17, 2006 10:21 AM
To: Fay Du
Subject: RE: [Cartoweb-users] Questions about about pgdijkstra
I'm sorry, I sill don't get the point.
But please, send mail to the mailing list only, not directly to me.
Le mardi 17 janvier 2006 à 09:29 -0500, Fay Du a écrit :
> No. The issue is related with shortest_path.
> -----Original Message-----
> From: cartoweb-users-bounces at lists.maptools.org
> [mailto:cartoweb-users-bounces at lists.maptools.org] On Behalf Of 
> Sylvain Pasche
> Sent: Tuesday, January 17, 2006 4:55 AM
> To: Cartoweb users
> Subject: RE: [Cartoweb-users] Questions about about pgdijkstra
> Le lundi 16 janvier 2006 à 14:05 -0500, Fay Du a écrit :
> > > 
> > -- What I trying to say is, if I set directed=ture, if there is a 
> > segment S, which start point is A, end point is true, can a shortest

> > pass goes from point B to A when it passes Segment S? Do I have to 
> > physical set Segment S start point to point B, and end point to A? 
> > ie.
> > 
> >    When I use following select command:
> > Select astext(the_geom) from graphy where id=Sid;
> > In return "MULTILINESTRING", the first point has to be Point B's 
> > coordinate, and last point has to be A's coordinate?
> > 
> > If it is not necessary, how program know from Point B to A is 
> > allowed and Point A to B is not allowed?
> > 
> > Hope I explain myself clearly this time.
> > Fay
> > 
> Pgdijsktra does not use geometry. Geometries are only used for 
> instance with the assign_vertex_id() and shortest_path_as_geometry() 
> functions.
> Is your issue related to the use of one of these functions ?
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