pgr_withPointsVia
 Proposed¶
pgr_withPointsVia
 Route that goes through a list of vertices and/or
points.
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 ANYINTEGER and ANYNUMERICAL
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.
Availability
Version 3.4.0
New proposed function
pgr_withPointsVia
(One Via)
Description¶
Given a graph, a set of points on the graphs edges and a list of vertices, this function is equivalent to finding the shortest path between \(vertex_i\) and \(vertex_{i+1}\) (where \(vertex\) can be a vertex or a point on the graph) for all \(i < size\_of(via\;vertices)\).
 Route:
is a sequence of paths.
 Path:
is a section of the route.
The general algorithm is as follows:
Build the Graph with the new points.
The points identifiers will be converted to negative values.
The vertices identifiers will remain positive.
Execute a pgr_dijkstraVia  Proposed.
Signatures¶
One Via¶
[directed, strict, U_turn_on_edge]
(seq, path_id, path_seq, start_vid, end_vid, node, edge, cost, agg_cost, route_agg_cost)
 Example:
Find the route that visits the vertices \(\{ 6, 15, 1\}\) in that order on a directed graph.
SELECT * FROM pgr_withPointsVia(
'SELECT id, source, target, cost, reverse_cost FROM edges order by id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[6, 15, 1]);
seq  path_id  path_seq  start_vid  end_vid  node  edge  cost  agg_cost  route_agg_cost
+++++++++
1  1  1  6  15  6  4  0.3  0  0
2  1  2  6  15  7  8  1  0.3  0.3
3  1  3  6  15  11  9  1  1.3  1.3
4  1  4  6  15  16  16  1  2.3  2.3
5  1  5  6  15  15  1  0  3.3  3.3
6  2  1  15  1  15  3  1  0  3.3
7  2  2  15  1  10  2  1  1  4.3
8  2  3  15  1  6  1  0.6  2  5.3
9  2  4  15  1  1  2  0  2.6  5.9
(9 rows)
Parameters¶
Parameter 
Type 
Default 
Description 


SQL query as described. 


SQL query as described. 

via vertices 

Array of ordered vertices identifiers that are going to be visited.

Where:
 ANYINTEGER:
SMALLINT, INTEGER, BIGINT
 ANYNUMERICAL:
SMALLINT, INTEGER, BIGINT, REAL, FLOAT
Optional parameters¶
Column 
Type 
Default 
Description 





Via optional parameters¶
Parameter 
Type 
Default 
Description 









With points optional parameters¶
Parameter 
Type 
Default 
Description 




Value in [





Inner Queries¶
Edges SQL¶
Column 
Type 
Default 
Description 


ANYINTEGER 
Identifier of the edge. 


ANYINTEGER 
Identifier of the first end point vertex of the edge. 


ANYINTEGER 
Identifier of the second end point vertex of the edge. 


ANYNUMERICAL 
Weight of the edge ( 


ANYNUMERICAL 
1 
Weight of the edge (

Where:
 ANYINTEGER:
SMALLINT
,INTEGER
,BIGINT
 ANYNUMERICAL:
SMALLINT
,INTEGER
,BIGINT
,REAL
,FLOAT
Points SQL¶
Parameter 
Type 
Default 
Description 


ANYINTEGER 
value 
Identifier of the point.


ANYINTEGER 
Identifier of the “closest” edge to the point. 


ANYNUMERICAL 
Value in <0,1> that indicates the relative postition from the first end point of the edge. 




Value in [

Where:
 ANYINTEGER:
SMALLINT
,INTEGER
,BIGINT
 ANYNUMERICAL:
SMALLINT
,INTEGER
,BIGINT
,REAL
,FLOAT
Result columns¶
Column 
Type 
Description 



Sequential value starting from 1. 


Identifier of a path. Has value 1 for the first path. 


Relative position in the path. Has value 1 for the beginning of a path. 


Identifier of the starting vertex of the path. 


Identifier of the ending vertex of the path. 


Identifier of the node in the path from 


Identifier of the edge used to go from



Cost to traverse from 


Aggregate cost from 


Total cost from 
Note
When start_vid
, end_vid
and node
columns have negative values,
the identifier is for a Point.
Additional Examples¶
Use pgr_findCloseEdges in the Points SQL¶
Visit from vertex \(1\) to the two locations on the graph of point (2.9, 1.8) in order of closeness to the graph.
SELECT * FROM pgr_withPointsVia(
$e$ SELECT * FROM edges $e$,
$p$ SELECT edge_id, round(fraction::numeric, 2) AS fraction, side
FROM pgr_findCloseEdges(
$$SELECT id, geom FROM edges$$,
(SELECT ST_POINT(2.9, 1.8)),
0.5, cap => 2)
$p$,
ARRAY[1, 1, 2], details => true);
seq  path_id  path_seq  start_vid  end_vid  node  edge  cost  agg_cost  route_agg_cost
+++++++++
1  1  1  1  1  1  6  1  0  0
2  1  2  1  1  3  7  1  1  1
3  1  3  1  1  7  8  0.9  2  2
4  1  4  1  1  2  8  0.1  2.9  2.9
5  1  5  1  1  11  9  1  3  3
6  1  6  1  1  16  16  1  4  4
7  1  7  1  1  15  3  1  5  5
8  1  8  1  1  10  5  0.8  6  6
9  1  9  1  1  1  1  0  6.8  6.8
10  2  1  1  2  1  5  0.2  0  6.8
11  2  2  1  2  11  8  0.1  0.2  7
12  2  3  1  2  2  2  0  0.3  7.1
(12 rows)
Point \(1\) corresponds to the closest edge from point (2.9, 1.8).
Point \(2\) corresponds to the next close edge from point (2.9, 1.8).
Point \(2\) is visited on the route to from vertex \(1\) to Point \(1\) (See row where \(seq = 4\)).
Usage variations¶
All this examples are about the route that visits the vertices \(\{1, 7, 3, 16, 15\}\) in that order on a directed graph.
SELECT * FROM pgr_withPointsVia(
'SELECT id, source, target, cost, reverse_cost FROM edges order by id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[1, 7, 3, 16, 15]);
seq  path_id  path_seq  start_vid  end_vid  node  edge  cost  agg_cost  route_agg_cost
+++++++++
1  1  1  1  7  1  1  0.6  0  0
2  1  2  1  7  6  4  1  0.6  0.6
3  1  3  1  7  7  1  0  1.6  1.6
4  2  1  7  3  7  10  1  0  1.6
5  2  2  7  3  8  12  0.6  1  2.6
6  2  3  7  3  3  1  0  1.6  3.2
7  3  1  3  16  3  12  0.4  0  3.2
8  3  2  3  16  12  13  1  0.4  3.6
9  3  3  3  16  17  15  1  1.4  4.6
10  3  4  3  16  16  1  0  2.4  5.6
11  4  1  16  15  16  16  1  0  5.6
12  4  2  16  15  15  2  0  1  6.6
(12 rows)
Aggregate cost of the third path.¶
SELECT agg_cost FROM pgr_withPointsVia(
'SELECT id, source, target, cost, reverse_cost FROM edges order by id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[1, 7, 3, 16, 15])
WHERE path_id = 3 AND edge < 0;
agg_cost

2.4
(1 row)
Route’s aggregate cost of the route at the end of the third path.¶
SELECT route_agg_cost FROM pgr_withPointsVia(
'SELECT id, source, target, cost, reverse_cost FROM edges order by id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[1, 7, 3, 16, 15])
WHERE path_id = 3 AND edge < 0;
route_agg_cost

5.6
(1 row)
Nodes visited in the route.¶
SELECT row_number() over () as node_seq, node
FROM pgr_withPointsVia(
'SELECT id, source, target, cost, reverse_cost FROM edges order by id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[1, 7, 3, 16, 15])
WHERE edge <> 1 ORDER BY seq;
node_seq  node
+
1  1
2  6
3  7
4  8
5  3
6  12
7  17
8  16
9  15
(9 rows)
The aggregate costs of the route when the visited vertices are reached.¶
SELECT path_id, route_agg_cost FROM pgr_withPointsVia(
'SELECT id, source, target, cost, reverse_cost FROM edges order by id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[1, 7, 3, 16, 15])
WHERE edge < 0;
path_id  route_agg_cost
+
1  1.6
2  3.2
3  5.6
4  6.6
(4 rows)
Status of “passes in front” or “visits” of the nodes and points.¶
SELECT seq, node,
CASE WHEN edge = 1 THEN 'visits'
ELSE 'passes in front'
END as status
FROM pgr_withPointsVia(
'SELECT id, source, target, cost, reverse_cost FROM edges order by id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[1, 7, 3, 16, 15], details => true)
WHERE agg_cost <> 0 or seq = 1;
seq  node  status
++
1  1  passes in front
2  6  passes in front
3  6  passes in front
4  7  visits
6  8  passes in front
7  3  visits
9  12  passes in front
10  17  passes in front
11  2  passes in front
12  16  visits
14  15  passes in front
(11 rows)
See Also¶
Indices and tables