pgr_withPointsCost - Proposed - pgRouting Manual (3.2)
pgr_withPointsCost - Proposed
pgr_withPointsCost
- 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.
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They are not officially in the current release.
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They will likely officially be part of the next mayor release:
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The functions make use of ANY-INTEGER and ANY-NUMERICAL
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Name might not change. (But still can)
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Signature might not change. (But still can)
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Functionality might not change. (But still can)
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pgTap tests have being done. But might need more.
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Documentation might need refinement.
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Availability
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Version 3.2.0
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New proposed function:
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pgr_withPointsCost(Combinations)
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Version 2.2.0
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New proposed function
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Description
Modify the graph to include points defined by points_sql. Using Dijkstra algorithm, return only the aggregate cost of the shortest path(s) found.
- The main characteristics are:
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It does not return a path.
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Returns the sum of the costs of the shortest path for pair combination of vertices in the modified graph.
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Vertices of the graph are:
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positive when it belongs to the edges_sql
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negative when it belongs to the points_sql
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Process is done only on edges with positive costs.
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Values are returned when there is a path.
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The returned values are in the form of a set of (start_vid, end_vid, agg_cost) .
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When the starting vertex and ending vertex are the same, there is no path.
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The agg_cost in the non included values (v, v) is 0
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When the starting vertex and ending vertex are the different and there is no path.
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The agg_cost in the non included values (u, v) is \(\infty\)
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If the values returned are stored in a table, the unique index would be the pair: (start_vid, end_vid) .
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For undirected graphs, the results are symmetric .
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The agg_cost of (u, v) is the same as for (v, u) .
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For optimization purposes, any duplicated value in the start_vids or end_vids is ignored.
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The returned values are ordered:
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start_vid ascending
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end_vid ascending
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Running time: \(O( start\_vids * (V \log V + E))\)
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Signatures
Summary
pgr_withPointsCost(edges_sql, points_sql, from_vid, to_vid [, directed] [, driving_side])
pgr_withPointsCost(edges_sql, points_sql, from_vid, to_vids [, directed] [, driving_side])
pgr_withPointsCost(edges_sql, points_sql, from_vids, to_vid [, directed] [, driving_side])
pgr_withPointsCost(edges_sql, points_sql, from_vids, to_vids [, directed] [, driving_side])
pgr_withPointsCost(Edges SQL, Points SQL, Combinations SQL [, directed] [, driving_side] [, details])
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 defaults
pgr_withPointsCost(edges_sql, points_sql, start_vid, end_vid)
RETURNS SET OF (start_vid, end_vid, agg_cost)
- Example :
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From point \(1\) to point \(3\)
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For a directed graph.
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The driving side is set as b both. So arriving/departing to/from the point(s) can be in any direction.
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
-1, -3);
start_pid end_pid agg_cost
-----------+---------+----------
-1 -3 3.2
(1 row)
One to One
pgr_withPointsCost(edges_sql, points_sql, from_vid, to_vid [, directed] [, driving_side])
RETURNS SET OF (seq, node, edge, cost, agg_cost)
- Example :
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From point \(1\) to vertex \(3\) on an undirected graph.
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
-1, 3,
directed := false);
start_pid end_pid agg_cost
-----------+---------+----------
-1 3 1.6
(1 row)
One to Many
pgr_withPointsCost(edges_sql, points_sql, from_vid, to_vids [, directed] [, driving_side])
RETURNS SET OF (start_vid, end_vid, agg_cost)
- Example :
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From point \(1\) to point \(3\) and vertex \(5\) on a directed graph.
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
-1, ARRAY[-3,5]);
start_pid end_pid agg_cost
-----------+---------+----------
-1 -3 3.2
-1 5 1.6
(2 rows)
Many to One
pgr_withPointsCost(edges_sql, points_sql, from_vids, to_vid [, directed] [, driving_side])
RETURNS SET OF (start_vid, end_vid, agg_cost)
- Example :
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From point \(1\) and vertex \(2\) to point \(3\) on a directed graph.
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[-1,2], -3);
start_pid end_pid agg_cost
-----------+---------+----------
-1 -3 3.2
2 -3 2.6
(2 rows)
Many to Many
pgr_withPointsCost(edges_sql, points_sql, from_vids, to_vids [, directed] [, driving_side])
RETURNS SET OF (start_vid, end_vid, agg_cost)
- Example :
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From point \(1\) and vertex \(2\) to point \(3\) and vertex \(7\) on a directed graph.
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[-1,2], ARRAY[-3,7]);
start_pid end_pid agg_cost
-----------+---------+----------
-1 -3 3.2
-1 7 3.6
2 -3 2.6
2 7 3
(4 rows)
Combinations SQL
pgr_withPointsCost(Edges SQL, Points SQL, Combinations SQL [, directed] [, driving_side] [, details])
RETURNS SET OF (seq, path_seq, start_vid, end_vid, node, edge, cost, agg_cost)
- Example :
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Two (source, target) combinations: (from point \(1\) to vertex \(3\) ), and (from vertex \(2\) to point \(3\) ) with right side driving topology.
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
'SELECT * FROM ( VALUES (-1, 3), (2, -3) ) AS t(source, target)',
driving_side => 'r');
start_pid end_pid agg_cost
-----------+---------+----------
-1 3 6.4
2 -3 2.6
(2 rows)
Parameters
|
Parameter |
Type |
Description |
|---|---|---|
|
Edges SQL |
|
Edges query as described above. |
|
Points SQL |
|
Points query as described above. |
|
Combinations SQL |
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Combinations query as described below. |
|
start_vid |
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Starting vertex identifier. When negative: is a point’s pid. |
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end_vid |
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Ending vertex identifier. When negative: is a point’s pid. |
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start_vids |
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Array of identifiers of starting vertices. When negative: is a point’s pid. |
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end_vids |
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Array of identifiers of ending vertices. When negative: is a point’s pid. |
|
directed |
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(optional). When
|
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driving_side |
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Inner query
Edges query
|
Column |
Type |
Default |
Description |
|---|---|---|---|
|
id |
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Identifier of the edge. |
|
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source |
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Identifier of the first end point vertex of the edge. |
|
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target |
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Identifier of the second end point vertex of the edge. |
|
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cost |
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Weight of the edge (source, target)
|
|
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reverse_cost |
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-1 |
Weight of the edge (target, source) ,
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Where:
- ANY-INTEGER :
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SMALLINT, INTEGER, BIGINT
- ANY-NUMERICAL :
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SMALLINT, INTEGER, BIGINT, REAL, FLOAT
Points query
Description of the Points SQL query
- points_sql :
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an SQL query, which should return a set of rows with the following columns:
|
Column |
Type |
Description |
|---|---|---|
|
pid |
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(optional) Identifier of the point.
|
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edge_id |
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Identifier of the "closest" edge to the point. |
|
fraction |
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Value in <0,1> that indicates the relative postition from the first end point of the edge. |
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side |
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(optional) Value in [‘b’, ‘r’, ‘l’, NULL] indicating if the point is:
|
Where:
- ANY-INTEGER :
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smallint, int, bigint
- ANY-NUMERICAL :
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smallint, int, bigint, real, float
Combinations query
|
Column |
Type |
Default |
Description |
|---|---|---|---|
|
source |
|
Identifier of the first end point vertex of the edge. |
|
|
target |
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Identifier of the second end point vertex of the edge. |
Where:
- ANY-INTEGER :
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SMALLINT, INTEGER, BIGINT
Result Columns
|
Column |
Type |
Description |
|---|---|---|
|
start_vid |
|
Identifier of the starting vertex. When negative: is a point’s pid. |
|
end_vid |
|
Identifier of the ending point. When negative: is a point’s pid. |
|
agg_cost |
|
Aggregate cost from
|
Additional Examples
- Example :
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From point \(1\) and vertex \(2\) to point \(3\) and vertex \(7\) , with right side driving topology
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[-1,2], ARRAY[-3,7],
driving_side := 'l');
start_pid end_pid agg_cost
-----------+---------+----------
-1 -3 3.2
-1 7 3.6
2 -3 2.6
2 7 3
(4 rows)
- Example :
-
From point \(1\) and vertex \(2\) to point \(3\) and vertex \(7\) , with left side driving topology
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[-1,2], ARRAY[-3,7],
driving_side := 'r');
start_pid end_pid agg_cost
-----------+---------+----------
-1 -3 4
-1 7 4.4
2 -3 2.6
2 7 3
(4 rows)
- Example :
-
From point \(1\) and vertex \(2\) to point \(3\) and vertex \(7\) , does not matter driving side.
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[-1,2], ARRAY[-3,7],
driving_side := 'b');
start_pid end_pid agg_cost
-----------+---------+----------
-1 -3 3.2
-1 7 3.6
2 -3 2.6
2 7 3
(4 rows)
The queries use the Sample Data network.
See Also
Indices and tables