Comments on: Build your own routing solution

By: shabeerVC

shabeerVC — Thu, 30 Apr 2009 09:13:25 +0000

Hi Chris,
I am developing a routing application using openlayers and postgres. I successfully executed my routing query using dijikstra shortest path. and my query goes like this:
“SELECT rt.gid as geomId, astext(rt.the_geom) as geometry,rd_name as rd_name,length as len FROM road,(SELECT gid, the_geom FROM dijkstra_sp(‘road’,4352,4052) ) as rt WHERE road.gid=rt.gid;”

But my dijkstra_sp function [SELECT gid, the_geom FROM dijkstra_sp('road',4352,4052)] returns me a set of geometries of type line string which is not in an order. I am able to draw lines in map using these linestrings but fails to find the direction because the lines are not in sequential order. Is there any other function from which I can get a ordered set of linestring co-ordinates.

Can you please reply me quickly for my question.

Thanks in advance.

By: ali

ali — Tue, 04 Nov 2008 17:24:58 +0000

Would you make tutorial Dijkstra algorithm for Avenue (arc view), Please!!!
Thanks a lot

By: Dorian

Dorian — Fri, 13 Jun 2008 09:34:01 +0000

I found the solution:

You will have to modify dijkstra.c and add the following:

#ifdef PG_MODULE_MAGIC
PG_MODULE_MAGIC;
#endif

after the include section. Then reinstall the pgdijkstra by executing sudo make install. Finally, restart the postgresql server.

(yes, i saw you are using the windows version and i am not sure if this appy for windows as well, but… good luck!)

By: Dorian

Dorian — Fri, 13 Jun 2008 09:14:58 +0000

Hi!

Does anybody solved the “missing magic block” error?

Thanks!

By: Ivan

Ivan — Wed, 30 Apr 2008 09:44:02 +0000

I get an error when calling create_graph_tables;
ERROR: duplicate key value violates unique constraint “roads_edges_source_key”
CONTEXT: SQL statement “INSERT INTO roads_edges (id, source, target) VALUES (1393, ‘1550′, ‘91′)”
PL/pgSQL function “create_graph_tables” line 27 at EXECUTE statement

By: nishith

nishith — Wed, 02 Apr 2008 10:23:13 +0000

hi all,
The error about magic module ocurs in my case too.

psql:c:/program files/PostgreSQL/pgdijkstra/dijkstra.sql:32: ERROR: incompatible library “C:/Program Files/PostgreSQL/8.2/lib/libdijkstra.dll”: missing magic block
HINT: Extension libraries are required to use the PG_MODULE_MAGIC macro.

Can someone tell me what are the extension libraries and if it is the .dll we have it in the postgres installation’s \lib dir already.

thanks for any help in advance
nishith

By: Kusum

Kusum — Wed, 26 Mar 2008 12:33:19 +0000

Hii All
I read the blog in Build your own routing solution
But there is a problem when i do that ,i get an error on exectuion of dijkstra.sql.
i get an error as mentioned by robin also above

C:\Program Files\PostgreSQL\8.2\bin>psql -U robin roads -f “c:\program files\
PostgreSQL\pgdijkstra\dijkstra.sql”
CREATE TYPE
psql:c:/program files/PostgreSQL/pgdijkstra/dijkstra.sql:32: ERROR: incompatible library “C:/Program Files/PostgreSQL/8.2/lib/libdijkstra.dll”: missing magic block
HINT: Extension libraries are required to use the PG_MODULE_MAGIC macro.
CREATE FUNCTION
CREATE FUNCTION
CREATE FUNCTION

Please reply if you have found any resolution

Regards

Kusum

By: Free Software Downloads

Free Software Downloads — Thu, 11 Oct 2007 18:29:56 +0000

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By: Software Development Guide

Software Development Guide — Thu, 11 Oct 2007 09:18:33 +0000

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By: Robin

Robin — Thu, 28 Jun 2007 05:02:36 +0000

hi,

I have been trying to get the above implementation to work but i am getting the following error at step 6:

At the moment I have PostgreSQL 8.2 and the pgdijkstra package and nothing else. Am i missing anything?

Can someone who has successfully implemented the algorithm please post all the steps and software used or email me at robinojha@gmail.com.

thanks in advance,
Robin