[mapserver-users] optimal path between two points.

Stephen Woodbridge woodbri at swoodbridge.com
Tue Feb 3 15:44:10 EST 2009


Yup, the results from pgRouting look broken. You should repost to the 
pgRouting list and describe how you set up your data. What tolerances 
you used when you created the vertices_tmp table, etc. This is not 
relevant to the mapserver list.

-Steve W

Valeria Muñoz wrote:
> example
>  
> the query is optimal path between 887 y 852. :
> SELECT rt.gid, AsText(rt.the_geom) AS wkt,
>                    length(rt.the_geom) AS length, calle.gid
>                 FROM calle,
>                     (SELECT gid, the_geom
>                         FROM dijkstra_sp_delta(
>                             'calle',
>                             887,
>                             852,
>                             3000)
>                      ) as rt
>                 WHERE calle.gid=rt.gid;
> result:
>  
> "gid";"wkt";"length";"gid"
> 4389;"MULTILINESTRING((-71.1951327440651 
> -30.5911350429583,-71.1957462426904 -30.5912128948402,-71.1957861853043 
> -30.591219747929,-71.1958400125164 
> -30.591211719682))";0.000713367403530106;4389
> 4603;"MULTILINESTRING((-71.1939954028678 
> -30.5921681162637,-71.1939834234752 -30.5922241673576,-71.1938231446269 
> -30.5925509466888))";0.000421286769021393;4603
> 4331;"MULTILINESTRING((-71.1950174992082 
> -30.5919506007811,-71.1950526139385 
> -30.5916919152203))";0.000261057969957178;4331
> 4608;"MULTILINESTRING((-71.1938231446269 
> -30.5925509466888,-71.1937648360013 
> -30.5926358138883))";0.00010296765211197;4608
> RG
>  
> 2009/2/3 Stephen Woodbridge <woodbri at swoodbridge.com 
> <mailto:woodbri at swoodbridge.com>>
> 
>     This may be cause because you need to check the direction of the
>     line segments before you create a linestring to pass to the client.
>     If you route is something like
> 
>     segment source target
>      1        1     3
>      2        4     3
>      3        7     4
>     etc
> 
>     route (1,2,4,3,7,4) or 1,3,3,4) depending on how you assemble it is
>     not going to make sense.
> 
>     Then segment 2 needs to be reversed so it goes from 3 to 4 and
>     segment 3 needs to be reverse also. so you get:
> 
>     route (1,3,4,7).
> 
>     Also this is not really a mapserver issues and you should probably
>     pust this to the pgRouting list. It would alos help if you showed
>     some of the intermediate results. When you show a image and the
>     route is broken, most of us can look at the image and say "Yup,
>     looks like the route is broken!" We do not see what data you got out
>     of pgRouting, we do not know how that got passed to mapserver or
>     OpenLayers, there are a lot of places that you can break things. We
>     don't even know how data flows through your system or who/what is
>     rendering the route part of the image.
> 
>     -Steve
> 
>     Valeria Muñoz wrote:
> 
>         hi..
>          I am back again with my problem pgrouting.. I followed a little
>         tutorial works perfectly with the shapefile from the example,
>         but to use mine the result is not expected, generating lines are
>         not continuous, I think I missing some coordinates or something
>         to work with my shapefile.
>          attached image.
>          please help!!..
> 
>         2009/1/19 Valeria Muñoz <valemunoz at gmail.com
>         <mailto:valemunoz at gmail.com> <mailto:valemunoz at gmail.com
>         <mailto:valemunoz at gmail.com>>>
> 
> 
>            Hi
>                I would like to implement the service "optimum path between 2
>            points," can someone help me to be able to implement it?. The
>            general idea is that a user picks a point A and point B and a
>            display on the map the best route to get from point A to B.
>                RG...
> 
> 
> 
>         ------------------------------------------------------------------------
> 
> 
>         ------------------------------------------------------------------------
> 
> 
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