pgr_drivingDistance¶
Synopsis¶
Using Dijkstra algorithm, extracts all the nodes that have costs less than or equal to the value distance. The edges extracted will conform the corresponding spanning tree.
Signature Summary¶
pgr_drivingDistance(edges_sql, start_vid, distance)
pgr_drivingDistance(edges_sql, start_vid, distance, directed)
pgr_drivingDistance(edges_sql, start_vids, distance, directed, equicost)
RETURNS SET OF (seq, [start_vid,] node, edge, cost, agg_cost)
Signatures¶
Minimal Use¶
pgr_drivingDistance(edges_sql, start_vid, distance)
RETURNS SET OF (seq, node, edge, cost, agg_cost)
Driving Distance From A Single Starting Vertex¶
pgr_drivingDistance(edges_sql, start_vid, distance, directed)
RETURNS SET OF (seq, node, edge, cost, agg_cost)
Driving Distance From Multiple Starting Vertices¶
pgr_drivingDistance(edges_sql, start_vids, distance, directed, equicost)
RETURNS SET OF (seq, start_vid, node, edge, cost, agg_cost)
Description of the Signatures¶
Description of the edges_sql query¶
| edges_sql: | an SQL query, which should return a set of rows with the following columns: |
|---|
| Column | Type | Default | Description |
|---|---|---|---|
| id | ANY-INTEGER | Identifier of the edge. | |
| source | ANY-INTEGER | Identifier of the first end point vertex of the edge. | |
| target | ANY-INTEGER | Identifier of the second end point vertex of the edge. | |
| cost | ANY-NUMERICAL |
|
|
| reverse_cost | ANY-NUMERICAL | -1 |
|
Where:
| ANY-INTEGER: | SMALLINT, INTEGER, BIGINT |
|---|---|
| ANY-NUMERICAL: | SMALLINT, INTEGER, BIGINT, REAL, FLOAT |
Description of the parameters of the signatures¶
| Column | Type | Description |
|---|---|---|
| edges_sql | TEXT | SQL query as described above. |
| start_vid | BIGINT | Identifier of the starting vertex. |
| start_vids | ARRAY[ANY-INTEGER] | Array of identifiers of starting vertices. |
| distance | FLOAT | Upper limit for the inclusion of the node in the result. |
| directed | BOOLEAN | (optional). When false the graph is considered as Undirected. Default is true which considers the graph as Directed. |
| equicost | BOOLEAN | (optional). When true the node will only appear in the closest start_vid list. Default is false which resembles several calls using the single starting point signatures. Tie brakes are arbitrarely. |
Description of the return values¶
Returns set of (seq [, start_v], node, edge, cost, agg_cost)
| Column | Type | Description |
|---|---|---|
| seq | INTEGER | Sequential value starting from 1. |
| start_vid | INTEGER | Identifier of the starting vertex. |
| node | BIGINT | Identifier of the node in the path within the limits from start_vid. |
| edge | BIGINT | Identifier of the edge used to arrive to node. 0 when the node is the start_vid. |
| cost | FLOAT | Cost to traverse edge. |
| agg_cost | FLOAT | Aggregate cost from start_vid to node. |
Additional Examples¶
Examples for queries marked as directed with cost and reverse_cost columns¶
The examples in this section use the following Graph 1: Directed, with cost and reverse cost
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
2, 3
);
seq | node | edge | cost | agg_cost
-----+------+------+------+----------
1 | 2 | -1 | 0 | 0
2 | 1 | 1 | 1 | 1
3 | 5 | 4 | 1 | 1
4 | 6 | 8 | 1 | 2
5 | 8 | 7 | 1 | 2
6 | 10 | 10 | 1 | 2
7 | 7 | 6 | 1 | 3
8 | 9 | 9 | 1 | 3
9 | 11 | 12 | 1 | 3
10 | 13 | 14 | 1 | 3
(10 rows)
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
13, 3
);
seq | node | edge | cost | agg_cost
-----+------+------+------+----------
1 | 13 | -1 | 0 | 0
2 | 10 | 14 | 1 | 1
3 | 5 | 10 | 1 | 2
4 | 11 | 12 | 1 | 2
5 | 2 | 4 | 1 | 3
6 | 6 | 8 | 1 | 3
7 | 8 | 7 | 1 | 3
8 | 12 | 13 | 1 | 3
(8 rows)
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
array[2,13], 3
);
seq | from_v | node | edge | cost | agg_cost
-----+--------+------+------+------+----------
1 | 2 | 2 | -1 | 0 | 0
2 | 2 | 1 | 1 | 1 | 1
3 | 2 | 5 | 4 | 1 | 1
4 | 2 | 6 | 8 | 1 | 2
5 | 2 | 8 | 7 | 1 | 2
6 | 2 | 10 | 10 | 1 | 2
7 | 2 | 7 | 6 | 1 | 3
8 | 2 | 9 | 9 | 1 | 3
9 | 2 | 11 | 12 | 1 | 3
10 | 2 | 13 | 14 | 1 | 3
11 | 13 | 13 | -1 | 0 | 0
12 | 13 | 10 | 14 | 1 | 1
13 | 13 | 5 | 10 | 1 | 2
14 | 13 | 11 | 12 | 1 | 2
15 | 13 | 2 | 4 | 1 | 3
16 | 13 | 6 | 8 | 1 | 3
17 | 13 | 8 | 7 | 1 | 3
18 | 13 | 12 | 13 | 1 | 3
(18 rows)
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
array[2,13], 3, equicost:=true
);
seq | from_v | node | edge | cost | agg_cost
-----+--------+------+------+------+----------
1 | 2 | 2 | -1 | 0 | 0
2 | 2 | 1 | 1 | 1 | 1
3 | 2 | 5 | 4 | 1 | 1
4 | 2 | 6 | 8 | 1 | 2
5 | 2 | 8 | 7 | 1 | 2
6 | 2 | 7 | 6 | 1 | 3
7 | 2 | 9 | 9 | 1 | 3
8 | 13 | 13 | -1 | 0 | 0
9 | 13 | 10 | 14 | 1 | 1
10 | 13 | 11 | 12 | 1 | 2
11 | 13 | 12 | 13 | 1 | 3
(11 rows)
Examples for queries marked as undirected with cost and reverse_cost columns¶
The examples in this section use the following Graph 2: Undirected, with cost and reverse cost
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
2, 3, false
);
seq | node | edge | cost | agg_cost
-----+------+------+------+----------
1 | 2 | -1 | 0 | 0
2 | 1 | 1 | 1 | 1
3 | 3 | 2 | 1 | 1
4 | 5 | 4 | 1 | 1
5 | 4 | 3 | 1 | 2
6 | 6 | 8 | 1 | 2
7 | 8 | 7 | 1 | 2
8 | 10 | 10 | 1 | 2
9 | 7 | 6 | 1 | 3
10 | 9 | 16 | 1 | 3
11 | 11 | 12 | 1 | 3
12 | 13 | 14 | 1 | 3
(12 rows)
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
13, 3, false
);
seq | node | edge | cost | agg_cost
-----+------+------+------+----------
1 | 13 | -1 | 0 | 0
2 | 10 | 14 | 1 | 1
3 | 5 | 10 | 1 | 2
4 | 11 | 12 | 1 | 2
5 | 2 | 4 | 1 | 3
6 | 6 | 8 | 1 | 3
7 | 8 | 7 | 1 | 3
8 | 12 | 13 | 1 | 3
(8 rows)
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
array[2,13], 3, false
);
seq | from_v | node | edge | cost | agg_cost
-----+--------+------+------+------+----------
1 | 2 | 2 | -1 | 0 | 0
2 | 2 | 1 | 1 | 1 | 1
3 | 2 | 3 | 2 | 1 | 1
4 | 2 | 5 | 4 | 1 | 1
5 | 2 | 4 | 3 | 1 | 2
6 | 2 | 6 | 8 | 1 | 2
7 | 2 | 8 | 7 | 1 | 2
8 | 2 | 10 | 10 | 1 | 2
9 | 2 | 7 | 6 | 1 | 3
10 | 2 | 9 | 16 | 1 | 3
11 | 2 | 11 | 12 | 1 | 3
12 | 2 | 13 | 14 | 1 | 3
13 | 13 | 13 | -1 | 0 | 0
14 | 13 | 10 | 14 | 1 | 1
15 | 13 | 5 | 10 | 1 | 2
16 | 13 | 11 | 12 | 1 | 2
17 | 13 | 2 | 4 | 1 | 3
18 | 13 | 6 | 8 | 1 | 3
19 | 13 | 8 | 7 | 1 | 3
20 | 13 | 12 | 13 | 1 | 3
(20 rows)
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
array[2,13], 3, false, equicost:=true
);
seq | from_v | node | edge | cost | agg_cost
-----+--------+------+------+------+----------
1 | 2 | 2 | -1 | 0 | 0
2 | 2 | 1 | 1 | 1 | 1
3 | 2 | 3 | 2 | 1 | 1
4 | 2 | 5 | 4 | 1 | 1
5 | 2 | 4 | 3 | 1 | 2
6 | 2 | 6 | 8 | 1 | 2
7 | 2 | 8 | 7 | 1 | 2
8 | 2 | 7 | 6 | 1 | 3
9 | 2 | 9 | 16 | 1 | 3
10 | 13 | 13 | -1 | 0 | 0
11 | 13 | 10 | 14 | 1 | 1
12 | 13 | 11 | 12 | 1 | 2
13 | 13 | 12 | 13 | 1 | 3
(13 rows)
Examples for queries marked as directed with cost column¶
The examples in this section use the following Graph 3: Directed, with cost
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost FROM edge_table',
2, 3
);
seq | node | edge | cost | agg_cost
-----+------+------+------+----------
1 | 2 | -1 | 0 | 0
2 | 5 | 4 | 1 | 1
3 | 6 | 8 | 1 | 2
4 | 10 | 10 | 1 | 2
5 | 9 | 9 | 1 | 3
6 | 11 | 11 | 1 | 3
7 | 13 | 14 | 1 | 3
(7 rows)
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost FROM edge_table',
13, 3
);
seq | node | edge | cost | agg_cost
-----+------+------+------+----------
1 | 13 | -1 | 0 | 0
(1 row)
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost FROM edge_table',
array[2,13], 3
);
seq | from_v | node | edge | cost | agg_cost
-----+--------+------+------+------+----------
1 | 2 | 2 | -1 | 0 | 0
2 | 2 | 5 | 4 | 1 | 1
3 | 2 | 6 | 8 | 1 | 2
4 | 2 | 10 | 10 | 1 | 2
5 | 2 | 9 | 9 | 1 | 3
6 | 2 | 11 | 11 | 1 | 3
7 | 2 | 13 | 14 | 1 | 3
8 | 13 | 13 | -1 | 0 | 0
(8 rows)
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost FROM edge_table',
array[2,13], 3, equicost:=true
);
seq | from_v | node | edge | cost | agg_cost
-----+--------+------+------+------+----------
1 | 2 | 2 | -1 | 0 | 0
2 | 2 | 5 | 4 | 1 | 1
3 | 2 | 6 | 8 | 1 | 2
4 | 2 | 10 | 10 | 1 | 2
5 | 2 | 9 | 9 | 1 | 3
6 | 2 | 11 | 11 | 1 | 3
7 | 13 | 13 | -1 | 0 | 0
(7 rows)
Examples for queries marked as undirected with cost column¶
The examples in this section use the following Graph 4: Undirected, with cost
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost FROM edge_table',
2, 3, false
);
seq | node | edge | cost | agg_cost
-----+------+------+------+----------
1 | 2 | -1 | 0 | 0
2 | 1 | 1 | 1 | 1
3 | 5 | 4 | 1 | 1
4 | 6 | 8 | 1 | 2
5 | 8 | 7 | 1 | 2
6 | 10 | 10 | 1 | 2
7 | 3 | 5 | 1 | 3
8 | 7 | 6 | 1 | 3
9 | 9 | 9 | 1 | 3
10 | 11 | 12 | 1 | 3
11 | 13 | 14 | 1 | 3
(11 rows)
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost FROM edge_table',
13, 3, false
);
seq | node | edge | cost | agg_cost
-----+------+------+------+----------
1 | 13 | -1 | 0 | 0
2 | 10 | 14 | 1 | 1
3 | 5 | 10 | 1 | 2
4 | 11 | 12 | 1 | 2
5 | 2 | 4 | 1 | 3
6 | 6 | 8 | 1 | 3
7 | 8 | 7 | 1 | 3
8 | 12 | 13 | 1 | 3
(8 rows)
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost FROM edge_table',
array[2,13], 3, false
);
seq | from_v | node | edge | cost | agg_cost
-----+--------+------+------+------+----------
1 | 2 | 2 | -1 | 0 | 0
2 | 2 | 1 | 1 | 1 | 1
3 | 2 | 5 | 4 | 1 | 1
4 | 2 | 6 | 8 | 1 | 2
5 | 2 | 8 | 7 | 1 | 2
6 | 2 | 10 | 10 | 1 | 2
7 | 2 | 3 | 5 | 1 | 3
8 | 2 | 7 | 6 | 1 | 3
9 | 2 | 9 | 9 | 1 | 3
10 | 2 | 11 | 12 | 1 | 3
11 | 2 | 13 | 14 | 1 | 3
12 | 13 | 13 | -1 | 0 | 0
13 | 13 | 10 | 14 | 1 | 1
14 | 13 | 5 | 10 | 1 | 2
15 | 13 | 11 | 12 | 1 | 2
16 | 13 | 2 | 4 | 1 | 3
17 | 13 | 6 | 8 | 1 | 3
18 | 13 | 8 | 7 | 1 | 3
19 | 13 | 12 | 13 | 1 | 3
(19 rows)
SELECT * FROM pgr_drivingDistance(
'SELECT id, source, target, cost FROM edge_table',
array[2,13], 3, false, equicost:=true
);
seq | from_v | node | edge | cost | agg_cost
-----+--------+------+------+------+----------
1 | 2 | 2 | -1 | 0 | 0
2 | 2 | 1 | 1 | 1 | 1
3 | 2 | 5 | 4 | 1 | 1
4 | 2 | 6 | 8 | 1 | 2
5 | 2 | 8 | 7 | 1 | 2
6 | 2 | 3 | 5 | 1 | 3
7 | 2 | 7 | 6 | 1 | 3
8 | 2 | 9 | 9 | 1 | 3
9 | 13 | 13 | -1 | 0 | 0
10 | 13 | 10 | 14 | 1 | 1
11 | 13 | 11 | 12 | 1 | 2
12 | 13 | 12 | 13 | 1 | 3
(12 rows)
See Also¶
- pgr_alphaShape - Alpha shape computation
- pgr_pointsAsPolygon - Polygon around set of points
- Sample Data network.
Indices and tables