[pgrouting-users] driving_distance function nodes returned ok edges incomplete

Sandor Csaba sandor.csaba at viamap.hu
Wed Mar 23 05:05:42 EDT 2011

Hi List,

I'm trying to figure out how the driving_distance function works.

Here's my sql:

SELECT * FROM driving_distance('SELECT id::int4,f_junc::int4 AS
source,t_junc::int4 AS
target,ST_Length(ST_Transform(the_geom,23700))::float8 AS cost FROM

The nodes in the given distance are returned correctly, but in case of
edges some of them are returned, some other not.

See attached image:
Red dot is the starting point,
black dots are nodes returned by the function.
Red lines are the edges returned.
Blue lines are all the street network.

What am I doing wrong that not all the edges are returned in the
driving distance?

Thank you,

Sándor Csaba
szolgáltatási vezető
ViaMap Kft.
Székhely/postacím: 1132 Budapest, Váci út 60-62.

1076 Budapest, Garay u. 29-31. I. 1.
(EMLA Környezeti Management és Jog Egyesület)

Tel: +3630/9605853
Fax: +3617002542
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