I have the road networks from osm and I created topology.
I know that dijkstra algorithm works, because I calculated the shortest path from two point layers. Now I would like to calculate catchment area for my points (from first layer).
I checked, how works pgr_drivingDistance. The result is far from expected.
I tried these codes:
SELECT pgr_drivingDistance( 'select id, source, target, leng as cost from osm_roads' , 221, 1000) FROM osm_roads_vertices_pgr
where 221 is number of nodes. This code executed for a very long time and I had to stop it.
CREATE TABLE distances AS (SELECT a.node AS id, a.agg_cost AS distance, b.the_geom FROM pgr_drivingDistance( 'SELECT gid AS id, source, target, leng as cost FROM public.osm_roads', 221, 1000 ) a, osm_roads_vertices_pgr b WHERE a.node = b.id);
but in this case result had only one point (start point) and this is not true.
I attach two screenshots:
The first, result from PgAdmin.
What am I doing wrong? Do you have an idea, how can I iprove my code?
I'm using PostgreSQL 10 with PostGIS 2.5.2 and Pgrouting 2.6.2.