Envelope Returns Invalid Geometry

[cfis@…]

select astext(envelope(GeomFromText('POINT(-104 40)')))

'POLYGON((-104 40,-104 40,-104 40,-104 40,-104 40))'

This polygon is invalid.

According to Martin:

• This does look like a bug, or at least a porting problem in GEOS. In JTS, the envelope of a Point is itself a Point. This means that the return value is always a valid geometry, and thus can be safely used in further operations.

[benjubb@…]

This is a bug in PostGIS.