demo (#22) - Routing from point to point - Code not working (#353) - Message List

Hello!

At first i have to say thank you for making this project come so far! I am searching for a solution to route from a Point on a line to another point on a line. I wonder why this hasnt been implemented yet in pgrouting, because i think its (one of the) most used feature! I found two different ways to achieve this, but both ways dont work for me. What i got till now is routing with different algorithms on Openstreetmap data from and to vertices and edges. I have sucessfully calculated the nearest points on the nearest edge to my start and endpoints. I tried to fill the missing last part of the route with the tutorial from here : http://pgrouting.postlbs.org/wiki/LoadingtheCode5 But i could not get it working. The function throws errors on the following SQL statement:

SELECT
astext(give_we_wkt(".$startEdge['gid'].",".$ergebnis_nebengeometrie_anfang_gid.",'".
$point_on_line_anfang."'))

It says, that st_intersects is neither false nor true on:

SELECT INTO p ST_intersects(line,buffer($3,0.001));
FEHLER:  Funktion st_intersects(text, geometry) ist nicht eindeutig
ZEILE 1: SELECT ST_intersects( $1 ,buffer( $2 ,0.001))

I found out that there are multiple problems in the give_we_wkt function. First problem is, that the creation of the linestring ('line') in the functioncode fails. Here is the code:

line:= line || X(endgeometry[j])||' '||Y(endgeometry[j])||', '||X(endgeometry[j-1])||' '||Y(endgeometry[j-1]);

The problem is, that endgeometry[j-1] returns <NULL>, and because of that the line becomes NULL. If i use endgeometry[j-0.5] instead it works, but i dont know if this is a good idea. After correcting this the function still throws erros, because the second parameter seems to be parsed incorrectly. if i call the sql manually like this:

SELECT ST_intersects('LINESTRING(6.6463522 50.9528275, 6.6463522 50.9528275)',buffer('01010000003435BD6FE4CA1B405949C4F07B7D4940' ,0.001));

it works. But the give_we_wkt function seems to fill in the second parameter without the "'" and fails.

Then i found the "routing_core_smart.sql" wrapper, and tried to solve my problem with it. But also i cant get this working. After adding the function and calling the following:

SELECT gid, AsText(the_geom) AS the_geom
      FROM shootingstar_sp_smart('ways', 293, 761, 0.1, 'length','to_cost', true, true);

I got the answer, that the function doesnt exist:

FEHLER:  Funktion shootingstar_sp_smart(unknown, integer, integer, numeric, unknown, unknown, boolean, boolean) existiert nicht
ZEILE 2:       FROM shootingstar_sp_smart('ways', 293, 761, 0.1, 'len...

Could someone please help me with this? I dont know how to solve this problems and i am no expert in postgresql and postgis at the moment.

Is there maybe another / easier solution to route from one point to another?

Im using Postgis 1.5 and Postgresql 8.4

Thanks for answers in adavance!