In the following example, we will look at all users within a distance of three units from our starting point—that is, a proposed bike shop at node 2:
SELECT * FROM pgr_drivingDistance( 'SELECT id, source, target, cost FROM chp06.edge_table', 2, 3);
The preceding command gives the following output:
As usual, we just get a list from the pgr_drivingDistance table that, in this case, comprises sequence, node, edge cost, and aggregate cost. PgRouting, like PostGIS, gives us low-level functionality; we need to reconstruct what geometries we need from that low-level functionality. We can use that node ID to extract the geometries ...
