On 17.01.2013 16:01, Gerd Petermann wrote:
reg. test data: I did not yet try to understand why a short arc brakes routing. I assume it is because you can't calculate the bearing with an appropriate precision? I just know that I see error messages like "road ... contains zero length arc at ... " or "road ... contains consecutive identical nodes at ... " when I omit the removeShortArcs call. So, I'll try to run the first version of the patch against many tiles and see what happens. If I don't find a problem in Europe, it is likely that we don't need iteration.
OK?
Gerd
The reason As far as I can remember is that if we have the following situation # # # --- O UUU --- # # # Now consider both # and - U and O stand for streets. O must not be shorter than the routing resolution (which is twice the minimal distance we can put points), else O will be unroutable. I found out about it, by having a very short stretch of a road on a bridge, where directly after the bridge (or was is actually sharing a point with the bridge?) a crossing pops up. As soon as we made sure that O is ~5.4m the routing worked again. Im not sure if --- UUU --- with UUU being shorter than 5.4 works though. (UUU being e.g a bridge).