pgr_withPointsDD - Proposed¶
Name¶
pgr_withPointsDD - Returns the driving distance from a starting point.
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.
Synopsis¶
Modify the graph to include points and using Dijkstra algorithm, extracts all the nodes and points that have costs less than or equal to the value distance from the starting point. The edges extracted will conform the corresponding spanning tree.
Signature Summary¶
pgr_withPointsDD(edges_sql, points_sql, start_vid, distance)
pgr_withPointsDD(edges_sql, points_sql, start_vid, distance, directed, driving_side, details)
pgr_withPointsDD(edges_sql, points_sql, start_vids, distance, directed, driving_side, details, equicost)
RETURNS SET OF (seq, node, edge, cost, agg_cost)
Signatures¶
Minimal Use¶
- 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.
- No details are given about distance of other points of the query.
pgr_withPointsDD(edges_sql, points_sql, start_vid, distance)
directed:=true, driving_side:='b', details:=false)
RETURNS SET OF (seq, node, edge, cost, agg_cost)
Example: |
---|
SELECT * FROM pgr_withPointsDD(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
-1, 3.8);
seq | node | edge | cost | agg_cost
-----+------+------+------+----------
1 | -1 | -1 | 0 | 0
2 | 1 | 1 | 0.4 | 0.4
3 | 2 | 1 | 0.6 | 0.6
4 | 5 | 4 | 0.3 | 1.6
5 | 6 | 8 | 1 | 2.6
6 | 8 | 7 | 1 | 2.6
7 | 10 | 10 | 1 | 2.6
8 | 7 | 6 | 0.3 | 3.6
9 | 9 | 9 | 1 | 3.6
10 | 11 | 11 | 1 | 3.6
11 | 13 | 14 | 1 | 3.6
(11 rows)
Driving distance from a single point¶
Finds the driving distance depending on the optional parameters setup.
pgr_withPointsDD(edges_sql, points_sql, start_vids, distance,
directed:=true, driving_side:='b', details:=false)
RETURNS SET OF (seq, node, edge, cost, agg_cost)
Example: | Right side driving topology |
---|
SELECT * FROM pgr_withPointsDD(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
-1, 3.8,
driving_side := 'r',
details := true);
seq | node | edge | cost | agg_cost
-----+------+------+------+----------
1 | -1 | -1 | 0 | 0
2 | 1 | 1 | 0.4 | 0.4
3 | 2 | 1 | 1 | 1.4
4 | -6 | 4 | 0.7 | 2.1
5 | 5 | 4 | 0.3 | 2.4
6 | 6 | 8 | 1 | 3.4
7 | 8 | 7 | 1 | 3.4
8 | 10 | 10 | 1 | 3.4
(8 rows)
Driving distance from many starting points¶
Finds the driving distance depending on the optional parameters setup.
pgr_withPointsDD(edges_sql, points_sql, start_vids, distance,
directed:=true, driving_side:='b', details:=false, equicost:=false)
RETURNS SET OF (seq, 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 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 |
|
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 |
|
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_vid | ANY-INTEGER | Starting point id |
distance | ANY-NUMERICAL | Distance from the start_pid |
directed | BOOLEAN | (optional). When false the graph is considered as Undirected. Default is true which considers the graph as Directed. |
driving_side | CHAR |
|
details | BOOLEAN | (optional). When true the results will include the driving distance to the points with in the distance. Default is false which ignores other points of the points_sql. |
equicost | BOOLEAN | (optional). When true the nodes 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 arbitrary. |
Description of the return values¶
Returns set of (seq, node, edge, cost, agg_cost)
Column | Type | Description |
---|---|---|
seq | INT | row sequence. |
node | BIGINT | Identifier of the node within the Distance from start_pid. If details =: true a negative value is the identifier of a point. |
edge | BIGINT |
|
cost | FLOAT |
|
agg_cost | FLOAT |
|
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
Example: | Left side driving topology |
---|
SELECT * FROM pgr_withPointsDD(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
-1, 3.8,
driving_side := 'l',
details := true);
seq | node | edge | cost | agg_cost
-----+------+------+------+----------
1 | -1 | -1 | 0 | 0
2 | 2 | 1 | 0.6 | 0.6
3 | -6 | 4 | 0.7 | 1.3
4 | 5 | 4 | 0.3 | 1.6
5 | 1 | 1 | 1 | 1.6
6 | 6 | 8 | 1 | 2.6
7 | 8 | 7 | 1 | 2.6
8 | 10 | 10 | 1 | 2.6
9 | -3 | 12 | 0.6 | 3.2
10 | -4 | 6 | 0.7 | 3.3
11 | 7 | 6 | 0.3 | 3.6
12 | 9 | 9 | 1 | 3.6
13 | 11 | 11 | 1 | 3.6
14 | 13 | 14 | 1 | 3.6
(14 rows)
Example: | Does not matter driving side. |
---|
SELECT * FROM pgr_withPointsDD(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
-1, 3.8,
driving_side := 'b',
details := true);
seq | node | edge | cost | agg_cost
-----+------+------+------+----------
1 | -1 | -1 | 0 | 0
2 | 1 | 1 | 0.4 | 0.4
3 | 2 | 1 | 0.6 | 0.6
4 | -6 | 4 | 0.7 | 1.3
5 | 5 | 4 | 0.3 | 1.6
6 | 6 | 8 | 1 | 2.6
7 | 8 | 7 | 1 | 2.6
8 | 10 | 10 | 1 | 2.6
9 | -3 | 12 | 0.6 | 3.2
10 | -4 | 6 | 0.7 | 3.3
11 | 7 | 6 | 0.3 | 3.6
12 | 9 | 9 | 1 | 3.6
13 | 11 | 11 | 1 | 3.6
14 | 13 | 14 | 1 | 3.6
(14 rows)
The queries use the Sample Data network.
History
- Proposed in version 2.2
See Also¶
- pgr_drivingDistance - Driving distance using dijkstra.
- pgr_alphaShape - Alpha shape computation.
- pgr_pointsAsPolygon - Polygon around set of points.
Indices and tables