pgrouting: Using nodes instead of ways

Question

I want to compute the shortest path between two points origin=(34.052299,-118.1812657) destination=(34.141132,-117.853179).

Below is my workflow.

Step 1: Find the nearest nodes.

origin: the following returns 590279764

SELECT id
FROM nodes
ORDER BY st_distance(the_geom, st_setsrid(st_makepoint(-118.1812657, 34.052299), 4326))
LIMIT 1

destination: the following returns 123007528

SELECT id
FROM nodes
ORDER BY st_distance(the_geom, st_setsrid(st_makepoint(-117.853179, 34.141132), 4326))
LIMIT 1

Step 2: Compute shortest path between origin and destination.

SELECT *
FROM pgr_dijkstra(
    'SELECT gid as id, source, target, length AS cost FROM ways',
    590279764, 123007528, false, false
);

However when I execute this I get the following error.

ERROR:  Start vertex was not found.

********** Error **********

ERROR: Start vertex was not found.
SQL state: XX000

Why is this happening?

Answer 1

You should make sure that you can find your ID either in the source or the target column of your ways table. The ways table is the relevant one where the shortest path algorithms looks for the node ID's.

The nodes table is not necessary for pgRouting.