postgresql-9.5-pgrouting-doc 2.1.0-1 / usr / share / doc / postgresql-9.5-pgrouting-doc / html / en / _sources / src / common / doc / functions / create_vert_table.txt

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    pgRouting Manual
    Copyright(c) pgRouting Contributors

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.. _pgr_create_vert_table:

pgr_createVerticesTable 
===============================================================================

.. index:: 
	single: pgr_createVerticesTable(text,text,text,text,text)
	module: common

Name
-------------------------------------------------------------------------------

``pgr_createVerticesTable`` — Reconstructs the vertices table based on the source and target information.


Synopsis
-------------------------------------------------------------------------------

The function returns:

  - ``OK`` after the vertices table has been reconstructed.
  - ``FAIL`` when the vertices table was not reconstructed due to an error. 

.. code-block:: sql

	varchar pgr_createVerticesTable(text edge_table,  text the_geom:='the_geom'
                           text source:='source',text target:='target',text rows_where:='true')



Description
-------------------------------------------------------------------------------

.. Rubric:: Parameters

The reconstruction of the vertices table  function accepts the following parameters:

:edge_table: ``text`` Network table name. (may contain the schema name as well)
:the_geom: ``text``  Geometry column name of the network table. Default value is ``the_geom``.  
: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.

.. warning::

    The ``edge_table`` will be affected

        - An index will be created, if it doesn't exists, to speed up the process to the following columns:

           * ``the_geom``
           * ``source``
           * ``target``

The function returns:

  - ``OK`` after the vertices table has been reconstructed.

    * Creates a vertices table: <edge_table>_vertices_pgr.
    * Fills ``id`` and ``the_geom`` columns of the vertices table based on the source and target columns of the edge table.

  - ``FAIL`` when the vertices table was not reconstructed due to an error. 

    * 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 are the same.
    * The SRID of the geometry could not be determined.

.. rubric:: The Vertices Table

The vertices table is a requierment of the :ref:`pgr_analyzeGraph <pgr_analyze_graph>` and the :ref:`pgr_analyzeOneway <pgr_analyze_oneway>` functions.

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. See :ref:`pgr_analyzeGraph <pgr_analyze_graph>`.
:chk: ``integer``  Indicator that the vertex might have a problem. See :ref:`pgr_analyzeGraph <pgr_analyze_graph>`.
:ein: ``integer`` Number of vertices in the edge_table that reference this vertex as incoming. See :ref:`pgr_analyzeOneway <pgr_analyze_oneway>`.
:eout: ``integer`` Number of vertices in the edge_table that reference this vertex as outgoing. See :ref:`pgr_analyzeOneway <pgr_analyze_oneway>`. 
:the_geom: ``geometry`` Point geometry of the vertex.

.. rubric:: History

* Renamed in version 2.0.0

Usage when the edge table's columns MATCH the default values:
-------------------------------------------------------------------------------
 
.. rubric:: The simplest way to use pgr_createVerticesTable is: 

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('edge_table');


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

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('edge_table','the_geom','source','target');

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 source column ``source`` 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 source column. 
 | ``SELECT  pgr_createVerticesTable('edge_table','source','the_geom','target');``


.. rubric:: When using the named notation

The order of the parameters do not matter:

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('edge_table',the_geom:='the_geom',source:='source',target:='target');

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('edge_table',source:='source',target:='target',the_geom:='the_geom');

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

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('edge_table',source:='source');

.. rubric:: Selecting rows using rows_where parameter

Selecting rows based on the id.

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('edge_table',rows_where:='id < 10');

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

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('edge_table',rows_where:='the_geom && (select st_buffer(the_geom,0.5) FROM edge_table WHERE id=5)');

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

.. code-block:: sql

	DROP TABLE IF EXISTS otherTable;
	CREATE TABLE otherTable AS  (SELECT 100 AS gid, st_point(2.5,2.5) AS other_geom) ; 
	SELECT  pgr_createVerticesTable('edge_table',rows_where:='the_geom && (select st_buffer(othergeom,0.5) FROM otherTable WHERE gid=100)');



Usage when the edge table's columns DO NOT MATCH the default values:
-------------------------------------------------------------------------------
 
For the following table

.. code-block:: sql

	DROP TABLE IF EXISTS mytable;
	CREATE TABLE mytable AS (SELECT id AS gid, the_geom AS mygeom,source AS src ,target AS tgt FROM edge_table) ;

.. rubric:: Using positional notation: 

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

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('mytable','mygeom','src','tgt');

.. warning::  | An error would occur when the arguments are not given in the appropriate order: In this example, the column ``src`` 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 source column.
 | ``SELECT  pgr_createVerticesTable('mytable','src','mygeom','tgt');``


.. rubric:: When using the named notation

The order of the parameters do not matter:

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('mytable',the_geom:='mygeom',source:='src',target:='tgt');

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('mytable',source:='src',target:='tgt',the_geom:='mygeom');

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.


.. rubric:: Selecting rows using rows_where parameter

Selecting rows based on the gid.

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('mytable','mygeom','src','tgt',rows_where:='gid < 10');

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('mytable',source:='src',target:='tgt',the_geom:='mygeom',rows_where:='gid < 10');

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

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('mytable','mygeom','src','tgt',
	                            rows_where:='the_geom && (SELECT st_buffer(mygeom,0.5) FROM mytable WHERE gid=5)');

.. code-block:: sql

	 SELECT  pgr_createVerticesTable('mytable',source:='src',target:='tgt',the_geom:='mygeom',
	                            rows_where:='mygeom && (SELECT st_buffer(mygeom,0.5) FROM mytable WHERE id=5)');

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

.. code-block:: sql

	DROP TABLE IF EXISTS otherTable;
	CREATE TABLE otherTable AS  (SELECT 100 AS gid, st_point(2.5,2.5) AS other_geom) ; 
	SELECT  pgr_createVerticesTable('mytable','mygeom','src','tgt',
	                            rows_where:='the_geom && (SELECT st_buffer(othergeom,0.5) FROM otherTable WHERE gid=100)');

.. code-block:: sql

	SELECT  pgr_createVerticesTable('mytable',source:='src',target:='tgt',the_geom:='mygeom',
	                            rows_where:='the_geom && (SELECT st_buffer(othergeom,0.5) FROM otherTable WHERE gid=100)');



Examples
-------------------------------------------------------------------------------

.. code-block:: sql

	SELECT pgr_createVerticesTable('edge_table');
	NOTICE:  PROCESSING:
    NOTICE:  pgr_createVerticesTable('edge_table','the_geom','source','target','true')
    NOTICE:  Performing checks, pelase wait .....
    NOTICE:  Populating public.edge_table_vertices_pgr, please wait...
    NOTICE:    ----->   VERTICES TABLE CREATED WITH  17 VERTICES
    NOTICE:                                         FOR   18  EDGES
    NOTICE:    Edges with NULL geometry,source or target: 0
    NOTICE:                              Edges processed: 18
    NOTICE:  Vertices table for table public.edge_table is: public.edge_table_vertices_pgr
    NOTICE:  ----------------------------------------------
               
	 pgr_createVerticesTable 
	--------------------
	 OK
	(1 row)


The example uses the :ref:`sampledata` network.


See Also
-------------------------------------------------------------------------------

* :ref:`topology`  for an overview of a topology for routing algorithms.
* :ref:`pgr_createTopology <pgr_create_topology>` to create a topology based on the geometry.
* :ref:`pgr_analyze_graph` to analyze the edges and vertices of the edge table.
* :ref:`pgr_analyze_oneway` to analyze directionality of the edges.