pgr_analyzeGraph

pgr_analyzeGraph — Analyzes the network topology.

Availability

• Version 2.0.0

  • Official function

Description

The function returns:

• OK after the analysis has finished.

• FAIL when the analysis was not completed due to an error.

varchar pgr_analyzeGraph(text edge_table, double precision tolerance,
                   text the_geom:='the_geom', text id:='id',
                   text source:='source',text target:='target',text rows_where:='true')

Prerequisites

The edge table to be analyzed must contain a source column and a target column filled with id’s of the vertices of the segments and the corresponding vertices table <edge_table>_vertices_pgr that stores the vertices information.

• Use pgr_createVerticesTable to create the vertices table.

• Use pgr_createTopology to create the topology and the vertices table.

Parameters

The analyze graph function accepts the following parameters:

edge_table

text Network table name. (may contain the schema name as well)

tolerance

float8 Snapping tolerance of disconnected edges. (in projection unit)

the_geom

text Geometry column name of the network table. Default value is the_geom.

id

text Primary key column name of the network table. Default value is id.

source

text Source column name of the network table. Default value is source.

target

text Target column name of the network table. Default value is target.

rows_where

text Condition to select a subset or rows. Default value is true to indicate all rows.

The function returns:

• OK after the analysis has finished.

  • Uses the vertices table: <edge_table>_vertices_pgr.

  • Fills completely the cnt and chk columns of the vertices table.

  • Returns the analysis of the section of the network defined by rows_where

• FAIL when the analysis was not completed due to an error.

  • The vertices table is not found.

  • A required column of the Network table is not found or is not of the appropriate type.

  • The condition is not well formed.

  • The names of source , target or id are the same.

  • The SRID of the geometry could not be determined.

The Vertices Table

The vertices table can be created with pgr_createVerticesTable or pgr_createTopology

The structure of the vertices table is:

id

bigint Identifier of the vertex.

cnt

integer Number of vertices in the edge_table that reference this vertex.

chk

integer Indicator that the vertex might have a problem.

ein

integer Number of vertices in the edge_table that reference this vertex as incoming. See pgr_analyzeOneWay.

eout

integer Number of vertices in the edge_table that reference this vertex as outgoing. See pgr_analyzeOneWay.

the_geom

geometry Point geometry of the vertex.

Usage when the edge table’s columns MATCH the default values:

The simplest way to use pgr_analyzeGraph is:

SELECT  pgr_createTopology('edge_table',0.001, clean := true);
NOTICE:  PROCESSING:
NOTICE:  pgr_createTopology('edge_table', 0.001, 'the_geom', 'id', 'source', 'target', rows_where := 'true', clean := t)
NOTICE:  Performing checks, please wait .....
NOTICE:  Creating Topology, Please wait...
NOTICE:  -------------> TOPOLOGY CREATED FOR  18 edges
NOTICE:  Rows with NULL geometry or NULL id: 0
NOTICE:  Vertices table for table public.edge_table is: public.edge_table_vertices_pgr
NOTICE:  ----------------------------------------------
 pgr_createtopology
--------------------
 OK
(1 row)

SELECT  pgr_analyzeGraph('edge_table',0.001);
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target','true')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 2
NOTICE:                            Dead ends: 7
NOTICE:  Potential gaps found near dead ends: 1
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

When the arguments are given in the order described in the parameters:

SELECT  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target','true')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 2
NOTICE:                            Dead ends: 7
NOTICE:  Potential gaps found near dead ends: 1
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

We get the same result as the simplest way to use the function.

Warning

An error would occur when the arguments are not given in the appropriate order: In this example, the column id of the table mytable is passed to the function as the geometry column, and the geometry column the_geom is passed to the function as the id column.

SELECT  pgr_analyzeGraph('edge_table',0.001,'id','the_geom','source','target');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'id','the_geom','source','target','true')
NOTICE:  Performing checks, please wait ...
NOTICE:  Got function st_srid(bigint) does not exist
NOTICE:  ERROR: something went wrong when checking for SRID of id in table public.edge_table
 pgr_analyzegraph
------------------
 FAIL
(1 row)

When using the named notation

The order of the parameters do not matter:

SELECT  pgr_analyzeGraph('edge_table',0.001,the_geom:='the_geom',id:='id',source:='source',target:='target');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target','true')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 2
NOTICE:                            Dead ends: 7
NOTICE:  Potential gaps found near dead ends: 1
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

SELECT  pgr_analyzeGraph('edge_table',0.001,source:='source',id:='id',target:='target',the_geom:='the_geom');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target','true')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 2
NOTICE:                            Dead ends: 7
NOTICE:  Potential gaps found near dead ends: 1
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

Parameters defined with a default value can be omitted, as long as the value matches the default:

SELECT  pgr_analyzeGraph('edge_table',0.001,source:='source');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target','true')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 2
NOTICE:                            Dead ends: 7
NOTICE:  Potential gaps found near dead ends: 1
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

Selecting rows using rows_where parameter

Selecting rows based on the id. Displays the analysis a the section of the network.

SELECT  pgr_analyzeGraph('edge_table',0.001,rows_where:='id < 10');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target','id < 10')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 0
NOTICE:                            Dead ends: 4
NOTICE:  Potential gaps found near dead ends: 0
NOTICE:               Intersections detected: 0
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

Selecting the rows where the geometry is near the geometry of row with id =5 .

SELECT  pgr_analyzeGraph('edge_table',0.001,rows_where:='the_geom && (SELECT st_buffer(the_geom,0.05) FROM edge_table WHERE id=5)');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target','the_geom && (SELECT st_buffer(the_geom,0.05) FROM edge_table WHERE id=5)')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 0
NOTICE:                            Dead ends: 5
NOTICE:  Potential gaps found near dead ends: 0
NOTICE:               Intersections detected: 0
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

Selecting the rows where the geometry is near the geometry of the row with gid =100 of the table othertable.

CREATE TABLE otherTable AS  (SELECT 100 AS gid, st_point(2.5,2.5) AS other_geom) ;
SELECT 1
SELECT  pgr_analyzeGraph('edge_table',0.001,rows_where:='the_geom && (SELECT st_buffer(other_geom,1) FROM otherTable WHERE gid=100)');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target','the_geom && (SELECT st_buffer(other_geom,1) FROM otherTable WHERE gid=100)')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 2
NOTICE:                            Dead ends: 10
NOTICE:  Potential gaps found near dead ends: 1
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

Usage when the edge table’s columns DO NOT MATCH the default values:

For the following table

CREATE TABLE mytable AS (SELECT id AS gid, source AS src ,target AS tgt , the_geom AS mygeom FROM edge_table);
SELECT 18
SELECT pgr_createTopology('mytable',0.001,'mygeom','gid','src','tgt', clean := true);
NOTICE:  PROCESSING:
NOTICE:  pgr_createTopology('mytable', 0.001, 'mygeom', 'gid', 'src', 'tgt', rows_where := 'true', clean := t)
NOTICE:  Performing checks, please wait .....
NOTICE:  Creating Topology, Please wait...
NOTICE:  -------------> TOPOLOGY CREATED FOR  18 edges
NOTICE:  Rows with NULL geometry or NULL id: 0
NOTICE:  Vertices table for table public.mytable is: public.mytable_vertices_pgr
NOTICE:  ----------------------------------------------
 pgr_createtopology
--------------------
 OK
(1 row)

Using positional notation:

The arguments need to be given in the order described in the parameters:

SELECT  pgr_analyzeGraph('mytable',0.001,'mygeom','gid','src','tgt');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('mytable',0.001,'mygeom','gid','src','tgt','true')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 2
NOTICE:                            Dead ends: 7
NOTICE:  Potential gaps found near dead ends: 1
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

Warning

An error would occur when the arguments are not given in the appropriate order: In this example, the column gid of the table mytable is passed to the function as the geometry column, and the geometry column mygeom is passed to the function as the id column.

SELECT  pgr_analyzeGraph('mytable',0.0001,'gid','mygeom','src','tgt');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('mytable',0.0001,'gid','mygeom','src','tgt','true')
NOTICE:  Performing checks, please wait ...
NOTICE:  Got function st_srid(bigint) does not exist
NOTICE:  ERROR: something went wrong when checking for SRID of gid in table public.mytable
 pgr_analyzegraph
------------------
 FAIL
(1 row)

When using the named notation

The order of the parameters do not matter:

SELECT  pgr_analyzeGraph('mytable',0.001,the_geom:='mygeom',id:='gid',source:='src',target:='tgt');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('mytable',0.001,'mygeom','gid','src','tgt','true')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 2
NOTICE:                            Dead ends: 7
NOTICE:  Potential gaps found near dead ends: 1
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

SELECT  pgr_analyzeGraph('mytable',0.001,source:='src',id:='gid',target:='tgt',the_geom:='mygeom');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('mytable',0.001,'mygeom','gid','src','tgt','true')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 2
NOTICE:                            Dead ends: 7
NOTICE:  Potential gaps found near dead ends: 1
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

In this scenario omitting a parameter would create an error because the default values for the column names do not match the column names of the table.

Selecting rows using rows_where parameter

Selecting rows based on the id.

SELECT  pgr_analyzeGraph('mytable',0.001,'mygeom','gid','src','tgt',rows_where:='gid < 10');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('mytable',0.001,'mygeom','gid','src','tgt','gid < 10')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 0
NOTICE:                            Dead ends: 4
NOTICE:  Potential gaps found near dead ends: 0
NOTICE:               Intersections detected: 0
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

SELECT  pgr_analyzeGraph('mytable',0.001,source:='src',id:='gid',target:='tgt',the_geom:='mygeom',rows_where:='gid < 10');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('mytable',0.001,'mygeom','gid','src','tgt','gid < 10')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 0
NOTICE:                            Dead ends: 4
NOTICE:  Potential gaps found near dead ends: 0
NOTICE:               Intersections detected: 0
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

Selecting the rows WHERE the geometry is near the geometry of row with id =5 .

SELECT  pgr_analyzeGraph('mytable',0.001,'mygeom','gid','src','tgt',
    rows_where:='mygeom && (SELECT st_buffer(mygeom,1) FROM mytable WHERE gid=5)');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('mytable',0.001,'mygeom','gid','src','tgt','mygeom && (SELECT st_buffer(mygeom,1) FROM mytable WHERE gid=5)')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 1
NOTICE:                            Dead ends: 5
NOTICE:  Potential gaps found near dead ends: 0
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

SELECT  pgr_analyzeGraph('mytable',0.001,source:='src',id:='gid',target:='tgt',the_geom:='mygeom',
    rows_where:='mygeom && (SELECT st_buffer(mygeom,1) FROM mytable WHERE gid=5)');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('mytable',0.001,'mygeom','gid','src','tgt','mygeom && (SELECT st_buffer(mygeom,1) FROM mytable WHERE gid=5)')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 1
NOTICE:                            Dead ends: 5
NOTICE:  Potential gaps found near dead ends: 0
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

Selecting the rows WHERE the geometry is near the place=’myhouse’ of the table othertable. (note the use of quote_literal)

DROP TABLE IF EXISTS otherTable;
DROP TABLE
CREATE TABLE otherTable AS  (SELECT 'myhouse'::text AS place, st_point(2.5,2.5) AS other_geom) ;
SELECT 1
SELECT  pgr_analyzeGraph('mytable',0.001,'mygeom','gid','src','tgt',
    rows_where:='mygeom && (SELECT st_buffer(other_geom,1) FROM otherTable WHERE place='||quote_literal('myhouse')||')');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('mytable',0.001,'mygeom','gid','src','tgt','mygeom && (SELECT st_buffer(other_geom,1) FROM otherTable WHERE place='myhouse')')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 2
NOTICE:                            Dead ends: 10
NOTICE:  Potential gaps found near dead ends: 1
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

SELECT  pgr_analyzeGraph('mytable',0.001,source:='src',id:='gid',target:='tgt',the_geom:='mygeom',
    rows_where:='mygeom && (SELECT st_buffer(other_geom,1) FROM otherTable WHERE place='||quote_literal('myhouse')||')');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('mytable',0.001,'mygeom','gid','src','tgt','mygeom && (SELECT st_buffer(other_geom,1) FROM otherTable WHERE place='myhouse')')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 2
NOTICE:                            Dead ends: 10
NOTICE:  Potential gaps found near dead ends: 1
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

Additional Examples

SELECT  pgr_createTopology('edge_table',0.001, clean := true);
NOTICE:  PROCESSING:
NOTICE:  pgr_createTopology('edge_table', 0.001, 'the_geom', 'id', 'source', 'target', rows_where := 'true', clean := t)
NOTICE:  Performing checks, please wait .....
NOTICE:  Creating Topology, Please wait...
NOTICE:  -------------> TOPOLOGY CREATED FOR  18 edges
NOTICE:  Rows with NULL geometry or NULL id: 0
NOTICE:  Vertices table for table public.edge_table is: public.edge_table_vertices_pgr
NOTICE:  ----------------------------------------------
 pgr_createtopology
--------------------
 OK
(1 row)

SELECT pgr_analyzeGraph('edge_table', 0.001);
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target','true')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 2
NOTICE:                            Dead ends: 7
NOTICE:  Potential gaps found near dead ends: 1
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

SELECT  pgr_analyzeGraph('edge_table',0.001,rows_where:='id < 10');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target','id < 10')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 0
NOTICE:                            Dead ends: 4
NOTICE:  Potential gaps found near dead ends: 0
NOTICE:               Intersections detected: 0
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

SELECT  pgr_analyzeGraph('edge_table',0.001,rows_where:='id >= 10');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target','id >= 10')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 2
NOTICE:                            Dead ends: 8
NOTICE:  Potential gaps found near dead ends: 1
NOTICE:               Intersections detected: 1
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

SELECT  pgr_analyzeGraph('edge_table',0.001,rows_where:='id < 17');
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target','id < 17')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 0
NOTICE:                            Dead ends: 3
NOTICE:  Potential gaps found near dead ends: 0
NOTICE:               Intersections detected: 0
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

SELECT pgr_createTopology('edge_table', 0.001,rows_where:='id <17', clean := true);
NOTICE:  PROCESSING:
NOTICE:  pgr_createTopology('edge_table', 0.001, 'the_geom', 'id', 'source', 'target', rows_where := 'id <17', clean := t)
NOTICE:  Performing checks, please wait .....
NOTICE:  Creating Topology, Please wait...
NOTICE:  -------------> TOPOLOGY CREATED FOR  16 edges
NOTICE:  Rows with NULL geometry or NULL id: 0
NOTICE:  Vertices table for table public.edge_table is: public.edge_table_vertices_pgr
NOTICE:  ----------------------------------------------
 pgr_createtopology
--------------------
 OK
(1 row)

SELECT pgr_analyzeGraph('edge_table', 0.001);
NOTICE:  PROCESSING:
NOTICE:  pgr_analyzeGraph('edge_table',0.001,'the_geom','id','source','target','true')
NOTICE:  Performing checks, please wait ...
NOTICE:  Analyzing for dead ends. Please wait...
NOTICE:  Analyzing for gaps. Please wait...
NOTICE:  Analyzing for isolated edges. Please wait...
NOTICE:  Analyzing for ring geometries. Please wait...
NOTICE:  Analyzing for intersections. Please wait...
NOTICE:              ANALYSIS RESULTS FOR SELECTED EDGES:
NOTICE:                    Isolated segments: 0
NOTICE:                            Dead ends: 3
NOTICE:  Potential gaps found near dead ends: 0
NOTICE:               Intersections detected: 0
NOTICE:                      Ring geometries: 0
 pgr_analyzegraph
------------------
 OK
(1 row)

The examples use the Sample Data network.

See Also

• Topology - Family of Functions for an overview of a topology for routing algorithms.

• pgr_analyzeOneWay to analyze directionality of the edges.

• pgr_createVerticesTable to reconstruct the vertices table based on the source and target information.

• pgr_nodeNetwork to create nodes to a not noded edge table.

Indices and tables

• Index

• Search Page