pgr_withPointsCostMatrix - proposed¶

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

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-inside.jpeg — Boost Graph Inside¶

Availability

Version 2.2.0
- New proposed function

Description¶

TBD

Signatures¶

Summary

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.

Using default

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: Cost matrix for points \(\{1, 6\}\) and vertices \(\{3, 6\}\) on a directed graph

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: Cost matrix for points \(\{1, 6\}\) and vertices \(\{3, 6\}\) on an undirected graph

Returning a symmetrical cost matrix
Using the default side value on the points_sql query
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)

Parameters¶

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.

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 from `start_vid` to `end_vid`.

Inner query¶

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.