The magic of PgRouting is its pgr_ function family. You feed it a SQL query that returns edges with specific columns (source, target, cost), and it returns the optimal path.
SELECT * FROM pgr_dijkstra( 'SELECT gid AS id, source, target, cost, reverse_cost FROM roads', 1, -- start vertex 50, -- end vertex directed := true );
To follow this practical guide, you need a running PostgreSQL instance. PgRouting- A Practical Guide
Before writing queries, you need to enable the necessary extensions in your database. CREATE EXTENSION postgis; CREATE EXTENSION pgrouting; Use code with caution. 2. Preparing Your Data
SELECT * FROM pgr_dijkstra( 'SELECT id, source, target, cost, reverse_cost FROM my_roads', 10, -- Source Node ID 50, -- Target Node ID directed := true ); The magic of PgRouting is its pgr_ function family
Using pgr_kdijkstra (K-Dijkstra) to find the nearest hospital from 500 accident points.
First, we need to define our . Let's calculate cost in seconds (time-based routing is more realistic than distance). Before writing queries, you need to enable the
This populates the source and target columns and creates a vertices_tmp table containing all nodes.