Driving Distance - Category

• pgr_drivingDistance - Driving Distance based on Dijkstra’s algorithm

• pgr_primDD - Driving Distance based on Prim’s algorithm

• pgr_kruskalDD - Driving Distance based on Kruskal’s algorithm

• Post pocessing

  • pgr_alphaShape - Alpha shape computation

Proposed

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.

• pgr_withPointsDD - Proposed - Driving Distance based on pgr_withPoints

Calculate nodes that are within a distance.

• Extracts all the nodes that have costs less than or equal to the value distance.

• The edges extracted will conform to the corresponding spanning tree.

• Edge \((u, v)\) will not be included when:

  • The distance from the root to \(u\) > limit distance.

  • The distance from the root to \(v\) > limit distance.

  • No new nodes are created on the graph, so when is within the limit and is not within the limit, the edge is not included.

Parameters

Parameter	Type	Description
Edges SQL	TEXT	Edges SQL as described below.
Root vid	BIGINT	Identifier of the root vertex of the tree.
Root vids	ARRAY[ANY-INTEGER]	Array of identifiers of the root vertices. \(0\) values are ignored For optimization purposes, any duplicated value is ignored.
distance	FLOAT	Upper limit for the inclusion of a node in the result.

Where:

ANY-NUMERIC:

SMALLINT, INTEGER, BIGINT, REAL, FLOAT

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

Result columns

Returns set of (seq, depth, start_vid, pred, node, edge, cost, agg_cost)

Parameter	Type	Description
seq	BIGINT	Sequential value starting from \(1\).
depth	BIGINT	Depth of the node. \(0\) when node = start_vid. \(depth-1\) is the depth of pred
start_vid	BIGINT	Identifier of the root vertex.
pred	BIGINT	Predecessor of node. When node = start_vid then has the value node.
node	BIGINT	Identifier of node reached using edge.
edge	BIGINT	Identifier of the edge used to arrive from pred to node. \(-1\) when node = start_vid.
cost	FLOAT	Cost to traverse edge.
agg_cost	FLOAT	Aggregate cost from start_vid to node.

See Also

Indices and tables

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