ST_Envelope
ST_Envelope returns the minimum bounding box of the input geometry, as follows:
If the input geometry is empty, the returned geometry will be POINT EMPTY.
If the minimum bounding box of the input geometry degenerates to a point, the returned geometry is a point.
If none of the preceding is true, the function returns a counter-clockwise-oriented polygon whose vertices are the corners of the minimum bounding box.
For all nonempty input, the function operates on the 2D projection of the input geometry.
Syntax
ST_Envelope(geom)
Arguments
geom- A value of data type GEOMETRY or an expression that evaluates to a GEOMETRY type.
Return type
GEOMETRY
If geom is null, then null is returned.
Examples
RETURN ST_Envelope(ST_GeomFromText("POLYGON ((2 1, 4 3, 6 1, 5 5, 3 4, 2 1))")) POLYGON ((2 1, 6 1, 6 5, 2 5, 2 1))
