[pgrouting-users] Facing issue on node creation

Raghavan Krishnasamylakshmanaperumal rkrish20 at uic.edu
Mon Apr 21 12:51:25 PDT 2014

Hi All,

I am using pgr_nodeNetwork with threshold 0.00001 to create nodes and
pgr_createTopology with a threshold of 0.0001 on the GPS traces which I
have collected. The resultant graph from this data looks weird due to the
creation of nodes so close to each other as I have visualized in the
attached pictures. The black circles are the nodes and you could see that
they are created such a way they are overlapping densely. I thought using
pgr_nodeNetwork threshold could solve this issue but it did not help me in
this case.

If I increase the threshold above 0.00001, I get the following error

> psql:run_pgr_node_network.sql:1: ERROR:  getPoint4d_p: point offset out of
> range
> CONTEXT:  SQL statement "create temp table inter_loc on commit drop as (
> select * from (
>         (select l1id, l2id, st_linelocatepoint(line,source) as locus from
> intergeom)
>          union
>         (select l1id, l2id, st_linelocatepoint(line,target) as locus from
> intergeom)) as foo
>         where locus<>0 and locus<>1)"
> PL/pgSQL function pgr_nodenetwork(text,double precision,text,text,text)
> line 184 at EXECUTE statement

So the graph formed out of my GPS traces is so noisy and not able to use it
for any of my experiments. Please suggest if I can use any other function
or approach to make my graph with more cleaner structure.

Raghavan KL
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