CreateTopology — Creates a new topology schema and registers it in the topology.topology table.

`integer `

varchar **CreateTopology**(`topology_schema_name``)`

;

`integer `

varchar **CreateTopology**(`topology_schema_name`, integer `srid``)`

;

`integer `

varchar **CreateTopology**(`topology_schema_name`, integer `srid`, double precision `prec``)`

;

`integer `

varchar **CreateTopology**(`topology_schema_name`, integer `srid`, double precision `prec`, boolean `hasz``)`

;

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 tolerance `prec`

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

`hasz`

defaults to false if not specified.

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

Availability: 1.1

Enhanced: 2.0 added the signature accepting hasZ

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 ------ 2