pgr_drivingDistance¶

Name¶

pgr_drivingDistance - Returns the driving distance from a start node.

Boost Graph Inside

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.

The minimal signature:

pgr_drivingDistance(sql text, start_v bigint, distance float8)
  RETURNS SET OF (seq, node, edge, cost, agg_cost)

Driving Distance from a single starting point:

pgr_drivingDistance(sql text, start_vid bigint, distance float8, directed boolean)
  RETURNS SET OF (seq, node, edge, cost, agg_cost)

Driving Distance from a multiple starting points:

pgr_drivingDistance(sql text, start_vids anyarray, distance float8,
      directed boolean default true,
      equicost boolean default false)
  RETURNS SET OF (seq, start_vid, node, edge, cost, agg_cost)

Description of the SQL query¶

sql:

a SQL query, which should return a set of rows with the following columns:

SELECT id, source, target, cost [,reverse_cost] FROM edge_table

id:	`ANY-INTEGER` identifier of the edge.
source:	`ANY-INTEGER` identifier of the source vertex of the edge.
target:	`ANY-INTEGER` identifier of the target vertex of the edge.
cost:	`ANY-NUMERICAL` value of the edge traversal cost. A negative cost will prevent the edge (`source`, `target`) from being inserted in the graph.
reverse_cost:	`ANY-NUMERICAL` (optional) the value for the reverse traversal of the edge. A negative cost will prevent the edge (`target`, `source`) from being inserted in the graph.

Where:

ANY-INTEGER:	smallint, int, bigint
ANY-NUMERICAL:	smallint, int, bigint, real, float

Description of the parameters of the signatures¶

sql:	SQL query as decribed above.
start_v:	`BIGINT` id of the starting vertex.
start_v:	`array[ANY-INTEGER]` array of id 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_v` 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)

seq:	`INT` row sequence.
start_v:	`BIGINT` id of the starting vertex. Used when multiple starting vetrices are in the query.
node:	`BIGINT` id of the node within the limits from `start_v`.
edge:	`BIGINT` id of the edge used to arrive to `node`. `0` when the `node` is the `start_v`.
cost:	`FLOAT` cost to traverse `edge`.
agg_cost:	`FLOAT` total cost from `start_v` to `node`.

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)

The queries use the Sample Data network.

History

Renamed in version 2.0.0
Added functionality in version 2.1

pgRouting Manual (2.2)