pgr_withPointsCost  Proposed¶
Name¶
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
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 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.
Synopsis¶
Modify the graph to include points defined by points_sql. Using Dijkstra algorithm, return only the aggregate cost of the shortest path(s) found.
Characteristics:¶
 The main Characteristics are:
 It does not return a path.
 Returns the sum of the costs of the shortest path for pair combination of vertices in the modified graph.
 Vertices of the graph are:
 positive when it belongs to the edges_sql
 negative when it belongs to the points_sql
 Process is done only on edges with positive costs.
 Values are returned when there is a path.
 The returned values are in the form of a set of (start_vid, end_vid, agg_cost).
 When the starting vertex and ending vertex are the same, there is no path.
 The agg_cost in the non included values (v, v) is 0
 When the starting vertex and ending vertex are the different and there is no path.
 The agg_cost in the non included values (u, v) is \(\infty\)
 If the values returned are stored in a table, the unique index would be the pair: (start_vid, end_vid).
 For undirected graphs, the results are symmetric.
 The agg_cost of (u, v) is the same as for (v, u).
 For optimization purposes, any duplicated value in the start_vids or end_vids is ignored.
 The returned values are ordered:
 start_vid ascending
 end_vid ascending
 Running time: \(O( start\_vids  * (V \log V + E))\)
Signature Summary¶
pgr_withPointsCost(edges_sql, points_sql, start_vid, end_vid, directed, driving_side)
pgr_withPointsCost(edges_sql, points_sql, start_vid, end_vids, directed, driving_side)
pgr_withPointsCost(edges_sql, points_sql, start_vids, end_vid, directed, driving_side)
pgr_withPointsCost(edges_sql, points_sql, start_vids, end_vids, directed, driving_side)
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.
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.
pgr_withPointsCost(edges_sql, points_sql, start_vid, end_vid)
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example: 

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, start_vid, end_vid,
directed:=true, driving_side:='b')
RETURNS SET OF (seq, node, edge, cost, agg_cost)
Example: 

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, start_vid, end_vids,
directed:=true, driving_side:='b')
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example: 

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, start_vids, end_vid,
directed:=true, driving_side:='b')
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example: 

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, start_vids, end_vids,
directed:=true, driving_side:='b')
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example: 

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)
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  ANYINTEGER  Identifier of the edge.  
source  ANYINTEGER  Identifier of the first end point vertex of the edge.  
target  ANYINTEGER  Identifier of the second end point vertex of the edge.  
cost  ANYNUMERICAL 


reverse_cost  ANYNUMERICAL  1 

Where:
ANYINTEGER:  SMALLINT, INTEGER, BIGINT 

ANYNUMERICAL:  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  ANYINTEGER 

edge_id  ANYINTEGER  Identifier of the “closest” edge to the point. 
fraction  ANYNUMERICAL  Value in <0,1> that indicates the relative postition from the first end point of the edge. 
side  CHAR 

Where:
ANYINTEGER:  smallint, int, bigint 

ANYNUMERICAL:  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  ANYINTEGER  Starting vertex identifier. When negative: is a point’s pid. 
end_vid  ANYINTEGER  Ending vertex identifier. When negative: is a point’s pid. 
start_vids  ARRAY[ANYINTEGER]  Array of identifiers of starting vertices. When negative: is a point’s pid. 
end_vids  ARRAY[ANYINTEGER]  Array of identifiers of ending vertices. When negative: is a point’s pid. 
directed  BOOLEAN  (optional). When false the graph is considered as Undirected. Default is true which considers the graph as Directed. 
driving_side  CHAR 

Description of the return values¶
Returns set of (start_vid, end_vid, agg_cost)
Column  Type  Description 

start_vid  BIGINT  Identifier of the starting vertex. When negative: is a point’s pid. 
end_vid  BIGINT  Identifier of the ending point. When negative: is a point’s pid. 
agg_cost  FLOAT  Aggregate cost from start_vid to end_vid. 
Examples¶
Example:  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:  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:  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.
History
 Proposed in version 2.2