ST_ToSurface method

geometry-expression.ST_ToSurface()

ST_Surface If the geometry-expression is of type ST_Surface, return the geometry-expression. If the geometry-expression is a geometry collection with a single element of type ST_Surface, return that element. If the geometry-expression is the empty set, return an empty set of type ST_Polygon. Otherwise, raise an exception condition.
The spatial reference system identifier of the result is the same as the spatial reference system of the geometry-expression.

Converts the geometry to a surface. The logic is equivalent to that used for CAST( geometry-expression AS ST_Surface ).

If geometry-expression is already known to be an ST_Surface value, it is more efficient to use TREAT( geometry-expression AS ST_Surface ) than the ST_ToSurface method.

Note

By default, ST_ToSurface uses the original format for a geometry, if it is available. Otherwise, the internal format is used. For more information about internal and original formats, see STORAGE FORMAT clause, CREATE SPATIAL REFERENCE SYSTEM statement.

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

The following example returns the result Polygon EMPTY.

SELECT NEW ST_GeomCollection().ST_ToSurface()

ST_ToSurface method

Syntax

Returns

Remarks

Note

See also

Standards and compatibility

Example