Name
ST_Envelope — Returns a geometry representing the bounding box of a geometry.
Synopsis
geometry ST_Envelope(geometry g1);
Description
Returns the double-precision (float8) minimum bounding box for the supplied geometry, as a geometry.
The polygon is defined by the corner points of the bounding box
((MINX, MINY),
(MINX, MAXY),
(MAXX, MAXY),
(MAXX, MINY),
(MINX, MINY)). (PostGIS will add a
ZMIN/ZMAX coordinate as
well).
Degenerate cases (vertical lines, points) will return a geometry of
lower dimension than POLYGON, ie.
POINT or LINESTRING.
Availability: 1.5.0 behavior changed to output double precision instead of float4
This method implements the OGC Simple Features
Implementation Specification for SQL 1.1.
s2.1.1.1
This method implements the SQL/MM specification.
SQL-MM 3: 5.1.19
Examples
SELECT ST_Envelope('POINT(1 3)'::geometry);
POINT(1 3)
SELECT ST_Envelope('LINESTRING(0 0,1 3)'::geometry);
POLYGON((0 0,0 3,1 3,1 0,0 0))
SELECT ST_Envelope('POLYGON((0 0,0 1,1.0000001 1,1.0000001 0,0 0))'::geometry);
POLYGON((0 0,0 1,1.0000001 1,1.0000001 0,0 0))
SELECT ST_Envelope('POLYGON((0 0,0 1,1.0000000001 1,1.0000000001 0,0 0))'::geometry);
POLYGON((0 0,0 1,1.0000000001 1,1.0000000001 0,0 0))
SELECT Box3D(geom), Box2D(geom), ST_Envelope(geom) As envelopewkt
FROM (SELECT 'POLYGON((0 0,0 1000012333334.34545678,1.0000001 1,1.0000001 0,0 0))'::geometry As geom) As foo;
Envelope of a point and LineString.
SELECT ST_Envelope(ST_Collect(
'LINESTRING(55 75,125 150)',
ST_Point(20, 80)
)) As wktenv;
POLYGON((20 75,20 150,125 150,125 75,20 75))