Descrizione

Creates a new topology schema with name topology_name and registers it in the topology.topology table. Topologies must be uniquely named. The topology tables (edge_data, face, node,and relation are created in the schema. It returns the id of the topology.

The srid is the spatial reference system SRID for the topology. The SRID defaults to -1 (unknown) if not specified.

The tolerance prec is measured in the units of the spatial reference system. The tolerance defaults to 0.

hasz defaults to false if not specified.

topoid optional explicit identifier (allows deterministic topology id assignment, needs to be unique)

useslargeids optional, defaults to false. If true, the topology will be created to support large ids (int8) for topology and primitive ids.

This is similar to the SQL/MM ST_InitTopoGeo but has more functionality.

Availability: 1.1

Enhanced: 2.0 added the signature accepting hasZ

Esempi

Create a topology schema called ma_topo that stores edges and nodes in Massachusetts State Plane-meters (SRID = 26986). The tolerance represents 0.5 meters since the spatial reference system is meter-based.

SELECT topology.CreateTopology('ma_topo', 26986, 0.5);

Create a topology for Rhode Island called ri_topo in spatial reference system State Plane-feet (SRID = 3438)

SELECT topology.CreateTopology('ri_topo', 3438) AS topoid;
topoid
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2

Si veda anche

Section 4.5, “Spatial Reference Systems”, ST_InitTopoGeo, Topology_Load_Tiger