ST_Perimeter(VARCHAR(128)) method

Syntax

multisurface-expression.ST_Perimeter(VARCHAR(128) unit_name)

Parameters

• unit_name – The units in which the perimeter should be computed. Defaults to the unit of the spatial reference system. The unit name must match the UNIT_NAME column of a row in the ST_UNITS_OF_MEASURE view where UNIT_TYPE is 'LINEAR'.

Returns

DOUBLE Returns the perimeter of the multi-surface.

Examples

• Example 1 – The following example creates a multi-surface containing two polygons and uses ST_Perimeter to find the length of the perimeter, returning the result 44.

  SELECT NEW ST_MultiSurface( NEW ST_Polygon('Polygon((0 0, 1 0, 1 1,0 1, 0 0))')
  , NEW ST_Polygon('Polygon((10 10, 20 10, 20 20,10 20, 10 10))') )
  .ST_Perimeter()

  The following example creates a multi-surface containing two polygons and an example unit of measure (example_unit_halfmetre). The ST_Perimeter method finds the length of the perimeter, returning the value 88.0.

  CREATE SPATIAL UNIT OF MEASURE IF NOT EXISTS  "example_unit_halfmetre" TYPE LINEAR CONVERT USING .5;
  SELECT NEW ST_MultiSurface( NEW ST_Polygon('Polygon((0 0, 1 0, 1 1,0 1, 0 0))')
  , NEW ST_Polygon('Polygon((10 10, 20 10, 20 20,10 20, 10 10))') )
  .ST_Perimeter('example_unit_halfmetre');

Standards

SQL/MM (ISO/IEC 13249-3: 2006) 9.5.4