pgRouting Manual (2.3)

pgr_withPointsCostMatrix - proposed

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pgr_withPointsCostMatrix - proposed

Name

pgr_withPointsCostMatrix - Calculates the shortest path and returns only the aggregate cost of the shortest path(s) found, for the combination of points given.

Warning

These are proposed functions for next mayor release.

  • They are not officially in the current release.
  • They will likely officially be part of the next mayor release:
    • The functions make use of ANY-INTEGER and ANY-NUMERICAL
    • Name might not change. (But still can)
    • Signature might not change. (But still can)
    • Functionality might not change. (But still can)
    • pgTap tests have being done. But might need more.
    • Documentation might need refinement.
../../../_images/boost-inside4.jpeg

Boost Graph Inside

Signature Summary

pgr_withPointsCostMatrix(edges_sql, points_sql, start_vids)
pgr_withPointsCostMatrix(edges_sql, points_sql, start_vids, directed, driving_side)
RETURNS SET OF (start_vid, end_vid, agg_cost)

Note

There is no details flag, unlike the other members of the withPoints family of functions.

Signatures

Minimal Signature

The minimal signature:
  • Is for a directed graph.
  • The driving side is set as b both. So arriving/departing to/from the point(s) can be in any direction.
pgr_withPointsCostMatrix(edges_sql, points_sql, start_vid)
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example:
SELECT * FROM pgr_withPointsCostMatrix(
    'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
    'SELECT pid, edge_id, fraction from pointsOfInterest',
    array[-1, 3, 6, -6]);
 start_vid | end_vid | agg_cost 
-----------+---------+----------
        -6 |      -1 |      1.3
        -6 |       3 |      4.3
        -6 |       6 |      1.3
        -1 |      -6 |      1.3
        -1 |       3 |      5.6
        -1 |       6 |      2.6
         3 |      -6 |      1.7
         3 |      -1 |      1.6
         3 |       6 |        1
         6 |      -6 |      1.3
         6 |      -1 |      2.6
         6 |       3 |        3
(12 rows)

Complete Signature

pgr_withPointsCostMatrix(edges_sql, points_sql, start_vids,
    directed:=true, driving_side:='b')
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example:returning a symmetrical cost matrix
  • Using the default side value on the points_sql query
  • Using an undirected graph
  • Using the default driving_side value
SELECT * FROM pgr_withPointsCostMatrix(
    'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
    'SELECT pid, edge_id, fraction from pointsOfInterest',
    array[-1, 3, 6, -6], directed := false);
 start_vid | end_vid | agg_cost 
-----------+---------+----------
        -6 |      -1 |      1.3
        -6 |       3 |      1.7
        -6 |       6 |      1.3
        -1 |      -6 |      1.3
        -1 |       3 |      1.6
        -1 |       6 |      2.6
         3 |      -6 |      1.7
         3 |      -1 |      1.6
         3 |       6 |        1
         6 |      -6 |      1.3
         6 |      -1 |      2.6
         6 |       3 |        1
(12 rows)

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  
Weight of the edge (source, target)
  • When negative: edge (source, target) does not exist, therefore it’s not part of the graph.
reverse_cost ANY-NUMERICAL -1
Weight of the edge (target, source),
  • When negative: edge (target, source) does not exist, therefore it’s not part of the graph.

Where:

ANY-INTEGER:SMALLINT, INTEGER, BIGINT
ANY-NUMERICAL:SMALLINT, INTEGER, BIGINT, REAL, FLOAT

Description of the Points SQL query

points_sql:an SQL query, which should return a set of rows with the following columns:
Column Type Description
pid ANY-INTEGER
(optional) Identifier of the point.
  • If column present, it can not be NULL.
  • If column not present, a sequential identifier will be given automatically.
edge_id ANY-INTEGER Identifier of the “closest” edge to the point.
fraction ANY-NUMERICAL Value in <0,1> that indicates the relative postition from the first end point of the edge.
side CHAR
(optional) Value in [‘b’, ‘r’, ‘l’, NULL] indicating if the point is:
  • In the right, left of the edge or
  • If it doesn’t matter with ‘b’ or NULL.
  • If column not present ‘b’ is considered.

Where:

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

Description of the parameters of the signatures

Parameter Type Description
edges_sql TEXT Edges SQL query as described above.
points_sql TEXT Points SQL query as described above.
start_vids ARRAY[ANY-INTEGER] Array of identifiers of starting vertices. When negative: is a point’s pid.
directed BOOLEAN (optional). When false the graph is considered as Undirected. Default is true which considers the graph as Directed.
driving_side CHAR
(optional) Value in [‘b’, ‘r’, ‘l’, NULL] indicating if the driving side is:
  • In the right or left or
  • If it doesn’t matter with ‘b’ or NULL.
  • If column not present ‘b’ is considered.

Description of the return values

Returns set of (start_vid, end_vid, agg_cost)

Column Type Description
start_vid BIGINT Identifier of the starting vertex.
end_vid BIGINT Identifier of the ending vertex.
agg_cost FLOAT Aggregate cost of the shortest path from start_vid to end_vid.

Examples

Example:Use with tsp
SELECT * FROM pgr_TSP(
    $$
    SELECT * FROM pgr_withPointsCostMatrix(
        'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
        'SELECT pid, edge_id, fraction from pointsOfInterest',
        array[-1, 3, 6, -6], directed := false);
    $$,
    randomize := false
);
 seq | node | cost | agg_cost 
-----+------+------+----------
   1 |   -6 |  1.3 |        0
   2 |   -1 |  1.6 |      1.3
   3 |    3 |    1 |      2.9
   4 |    6 |  1.3 |      3.9
   5 |   -6 |    0 |      5.2
(5 rows)

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