I am trying the driving distance function of pgRouting 2.0 beta, with an extract of OSM data. The problem i have is illustrated on the following image :
On this picture i try to get all the ways accessible in 5 min from the downtown of the small city. For this purpose, i use the driving distance function. Clearly, the result is not ok : ways that should be returned are not, ways that shouldn't are (and far away from the area).
I'm pretty sure it's a problem during the creation of the topology, so I've tried various tool to import data and create the topology : - osm2postgis, osmosis + pgr_createTopology function of pgRouting - osm2po With exactly the same kind of problem each time.
I've changed the tolerance of disconnected edge of the pgr_createTopology function and tried a large range of values, without success.
I haven't many experience in GIS, postgis and pgrouting, i would be very pleased if you have some tricks or an idea about the problem !
Thank you for your help !
(I'm using postgis 9.2 + pgRouting 2.0 beta)