Creation and visualization of isochrones in the road network from the police station in intervals: 2,5,10,15 min, if the speed of movement is 40km/h

Question

Here is the code which I have created for interval 2minutes

select ways.the_geom from                     
(WITH distance_query AS (
  SELECT *, 
         (length / 1000) / (30 / 3600) AS time_in_seconds
  FROM ways
)
SELECT * FROM 
pgr_drivingDistance('SELECT gid as id, 
                     source, target, 
                     cost FROM ways',
                    2338,
                    120)) as route 
left outer join ways ways 
  on ways.gid = route.edge  

The problem is, when I change the seconds(intervals) from 120 to 300, I get the same results always, I will be very grateful if anyone can help me!

Answer 1

The query is looking for points, but joining on edges.

Change the join condition to on ways.gid = route.node