pgr_withPointsDD - Proposed

pgr_withPointsDD - Returns the driving distance from a starting point.

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

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.

Signatures

pgr_withPointsDD(Edges SQL, Points SQL, Root vid, distance
   [, directed] [, driving_side] [, details])
pgr_withPointsDD(Edges SQL, Points SQL, Root vids, distance
   [, directed] [, driving_side] [, details] [, equicost])
RETURNS SET OF (seq, [start_vid,] node, edge, cost, agg_cost)

Single vertex

pgr_withPointsDD(Edges SQL, Points SQL, Root vid, distance
   [, directed] [, driving_side] [, details])
RETURNS SET OF (seq, node, edge, cost, agg_cost)
Example:

Right side driving topology, from point \(1\) within a distance of \(3.3\) with details.

SELECT * FROM pgr_withPointsDD(
  'SELECT id, source, target, cost, reverse_cost FROM edges ORDER BY id',
  'SELECT pid, edge_id, fraction, side from pointsOfInterest',
  -1, 3.3,
  driving_side => 'r',
  details => true);
 seq | node | edge | cost | agg_cost
-----+------+------+------+----------
   1 |   -1 |   -1 |    0 |        0
   2 |    5 |    1 |  0.4 |      0.4
   3 |    6 |    1 |    1 |      1.4
   4 |   -6 |    4 |  0.7 |      2.1
   5 |    7 |    4 |  0.3 |      2.4
(5 rows)

Multiple vertices

pgr_withPointsDD(Edges SQL, Points SQL, Root vids, distance
   [, directed] [, driving_side] [, details] [, equicost])
RETURNS SET OF (seq, start_vid, node, edge, cost, agg_cost)
Example:

From point \(1\) and vertex \(16\) within a distance of \(3.3\) with equicost on a directed graph

SELECT * FROM pgr_withPointsDD(
  'SELECT id, source, target, cost, reverse_cost FROM edges ORDER BY id',
  'SELECT pid, edge_id, fraction, side from pointsOfInterest',
  ARRAY[-1, 16], 3.3,
  driving_side => 'l',
  equicost => true);
 seq | start_vid | node | edge | cost | agg_cost
-----+-----------+------+------+------+----------
   1 |        -1 |   -1 |   -1 |    0 |        0
   2 |        -1 |    6 |    1 |  0.6 |      0.6
   3 |        -1 |    7 |    4 |    1 |      1.6
   4 |        -1 |    5 |    1 |    1 |      1.6
   5 |        -1 |    3 |    7 |    1 |      2.6
   6 |        -1 |    8 |   10 |    1 |      2.6
   7 |        16 |   16 |   -1 |    0 |        0
   8 |        16 |   11 |    9 |    1 |        1
   9 |        16 |   15 |   16 |    1 |        1
  10 |        16 |   17 |   15 |    1 |        1
  11 |        16 |   10 |    3 |    1 |        2
  12 |        16 |   12 |   11 |    1 |        2
(12 rows)

Parameters

Column

Type

Description

Edges SQL

TEXT

Edges SQL as described below

Points SQL

TEXT

Points SQL as described below

Root vid

BIGINT

Identifier of the root vertex of the tree.

  • Negative values represent a point

Root vids

ARRAY[ANY-INTEGER]

Array of identifiers of the root vertices.

  • Negative values represent a point

  • \(0\) values are ignored

  • For optimization purposes, any duplicated value is ignored.

distance

FLOAT

Upper limit for the inclusion of a node in the result.

Optional parameters

Column

Type

Default

Description

directed

BOOLEAN

true

  • When true the graph is considered Directed

  • When false the graph is considered as Undirected.

With points optional parameters

Parameter

Type

Default

Description

driving_side

CHAR

b

Value in [r, l, b] indicating if the driving side is:

  • r for right driving side.

  • l for left driving side.

  • b for both.

details

BOOLEAN

false

  • When true the results will include the points that are in the path.

  • When false the results will not include the points that are in the path.

Driving distance optional parameters

Column

Type

Default

Description

equicost

BOOLEAN

true

  • When true the node will only appear in the closest from_v list.

  • When false which resembles several calls using the single starting point signatures. Tie brakes are arbitrary.

Inner Queries

Edges SQL

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)

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

Points SQL

Parameter

Type

Default

Description

pid

ANY-INTEGER

value

Identifier of the point.

  • Use with positive value, as internally will be converted to negative value

  • If column is present, it can not be NULL.

  • If column is not present, a sequential negative value 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

b

Value in [b, r, l, NULL] indicating if the point is:

  • In the right r,

  • In the left l,

  • In both sides b, NULL

Where:

ANY-INTEGER:

SMALLINT, INTEGER, BIGINT

ANY-NUMERICAL:

SMALLINT, INTEGER, BIGINT, REAL, FLOAT

Result Columns

Returns SET OF (seq, [start_vid,] node, edge, cost, agg_cost)

Parameter

Type

Description

seq

BIGINT

Sequential value starting from \(1\).

[start_vid]

BIGINT

Identifier of the root vertex.

node

BIGINT

Identifier of node within the limits from from_v.

edge

BIGINT

Identifier of the edge used to arrive to node.

  • \(0\) when node = from_v.

cost

FLOAT

Cost to traverse edge.

agg_cost

FLOAT

Aggregate cost from from_v to node.

Where:

ANY-INTEGER:

SMALLINT, INTEGER, BIGINT

ANY-NUMERIC:

SMALLINT, INTEGER, BIGINT, REAL, FLOAT, NUMERIC

Additional Examples

Driving side does not matter

From point \(1\) within a distance of \(3.3\), does not matter driving side, with details.

SELECT * FROM pgr_withPointsDD(
  'SELECT id, source, target, cost, reverse_cost FROM edges ORDER BY id',
  'SELECT pid, edge_id, fraction, side from pointsOfInterest',
  -1, 3.3,
  driving_side => 'b',
  details => true);
 seq | node | edge | cost | agg_cost
-----+------+------+------+----------
   1 |   -1 |   -1 |    0 |        0
   2 |    5 |    1 |  0.4 |      0.4
   3 |    6 |    1 |  0.6 |      0.6
   4 |   -6 |    4 |  0.7 |      1.3
   5 |    7 |    4 |  0.3 |      1.6
   6 |    3 |    7 |    1 |      2.6
   7 |    8 |   10 |    1 |      2.6
   8 |   11 |    8 |    1 |      2.6
   9 |   -3 |   12 |  0.6 |      3.2
  10 |   -4 |    6 |  0.7 |      3.3
(10 rows)

See Also

Indices and tables