Returns a rectangle defined as the envelope of two points.
The constructor is equivalent to the following: NEW ST_MultiPoint( pmin, pmax ).ST_Envelope()
If the input points do not specify the corresponding corners of a rectangle, the server will determine the correct containing
rectangle for the specified points.
If input points are in a round-Earth spatial reference system, the produced polygon will not be an axis-aligned rectangle.
The eastern and western boundaries will coincide with the meridians between the eastern and western point pairs, respectively,
while the northern and southern edges will not coincide with the parallels and will rather follow great elliptical arches
containing the edge end points. Additionally, the server will always generate a valid polygon, if possible. If such a valid
polygon crosses the date line, longitude of the western points will be higher than that of the eastern points, counter to
the relationship for polygons not crossing the date line.