PostGIS

TopoElement
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TopoElement

10.2. Topology Domains

Name

TopoElement — An array of 2 integers generally used to identify a TopoGeometry component.

Description

An array of 2 integers used to represent one component of a simple or hierarchical TopoGeometry.

In the case of a simple TopoGeometry the first element of the array represents the identifier of a topological primitive and the second element represents its type (1:node, 2:edge, 3:face). In the case of a hierarchical TopoGeometry the first element of the array represents the identifier of a child TopoGeometry and the second element represents its layer identifier.

For any given hierarchical TopoGeometry all child TopoGeometry elements will come from the same child layer, as specified in the topology.layer record for the layer of the TopoGeometry being defined.

Examples

SELECT te[1] AS id, te[2] AS type FROM
( SELECT ARRAY[1,2]::topology.topoelement AS te ) f;
 id | type
----+------
  1 |    2

SELECT ARRAY[1,2]::topology.topoelement;
  te
-------
 {1,2}

--Example of what happens when you try to case a 3 element array to topoelement
-- NOTE: topoement has to be a 2 element array so fails dimension check
SELECT ARRAY[1,2,3]::topology.topoelement;
ERROR:  value for domain topology.topoelement violates check constraint "dimensions"

PostGIS

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Examples

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