Sam Giffney wrote:
On Postgis 1.3.2 (tested on Windows and Debian Lenny)
A LINESTRING which runs "parallel to the grid lines" (excuse my poor
GIS terminology) returns a LINESTRING instead of a POLYGON for the
envelope.
postgis=> select
ST_AsText(ST_Envelope(ST_GeomFromText('LINESTRING(-36.91410
174.90900,-36.91410 174.91017)')));
st_astext
-------------------------------------------------
LINESTRING(-36.9141 174.909,-36.9141 174.91017)
(1 row)
The documentation states that ST_Envelope should return a POLYGON.
I think I understand why the LINESTRING is returned, but shouldn't the
documentation list that as an option?
Cheers,
Sam
Hi Sam,
It is the documentation that is wrong. The change was made in order to
ensure that only valid geometries can be returned from the ST_Envelope()
/ bounding box functions. See
http://postgis.refractions.net/pipermail/postgis-commits/2007-October/000180.html
for more information. Any doc patches gratefully received :)
ATB,
Mark.
--
Mark Cave-Ayland
Sirius Corporation - The Open Source Experts
http://www.siriusit.co.uk
T: +44 870 608 0063
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