# Killing some bugs (wrong path calculation)¶

At this point you will find out that some routes are not correct.

Please use the following extent in Openlayers

```
map.zoomToExtent(new OpenLayers.Bounds(894000,
6850300,
894500,
6850600));
```

For example you get a wrong path like:

What you see in here in blue is the number of the vertices.

The three figures (black on grey) are the gid,the source-id and the target-id of a Multilinestring.

By looking at the screenshot obviously the shortest path is via “Edinghäuser Straße”, why is the route so, let`s say “weird”?

The start point is at the Multilinestring with the gid 2200, the source-id is the number 1363. The end point is at the Multilinestring with the gid 4220, the target_id is 2446.

Iy you the vertives 1363 and 2446 you understand why it goes that path, remember: The function for this is:

```
SELECT gid, the_geom
FROM dijkstra_sp_delta(
'".TABLE."',
".$startEdge['source'].",
".$endEdge['target'].",
3000
```

One solution is to do the calculation “twice”, one as seen, and one more the other way round

```
SELECT gid, the_geom
FROM dijkstra_sp_delta(
'".TABLE."',
".$endEdge['source'].",
".$startEdge['target'].",
3000
```

What will calculate from node 2445 on the Multilinestring 4220 to 1364 on Multiline 2200.