I am using the Dijkstra shortest path algorithm to plot a route between two points using the latest version of pgrouting in postgresql 9.1 with postGIS 2.0.1.
I am able to get a correct result however the edges are in the wrong order so when I plot it in my app it does not draw correctly.
I have read several other posts with people having the same problem but none of the solutions provided have worked for me.
Here was the original query I was using:
SELET rt.gid, ST_AsGeoJson(rt.the_geom) AS coordinates, hh_2po_4pgr.gid FROM hh_2po_4pgr, (SELECT gid, the_geom FROM dijkstra_sp_delta('hh_2po_4pgr', 336, 557, 0.1)) as rt WHERE hh_2po_4pgr.gid=rt.gid;
I then read a post which suggested doing it this way to order by the id:
select rank, gid, ST_AsGeoJson(the_geom) FROM ( select edge_id, ROW_NUMBER() OVER (PARTITION BY 1) as rank from shortest_path( 'SELECT gid as id, source::integer, target::integer, length::double precision as cost FROM hh_2po_4pgr', 557, 350, false, false) ) as route join hh_2po_4pgr h on h.gid = edge_id order by rank;
This worked for one of my route finding queries but I have tried it with others and it doesn't work.
I read this:
which says the wrappers return an id which can be used to preserve order so I then created this query:
SELECT id, gid, ST_AsGeoJson(the_geom) FROM dijkstra_sp('hh_2po_4pgr', 557, 350)
but the ordering is still not correct.
Is there any way to fix this?