Thanks for the response, especially as it was truncated by an accidental
premature send.
I have solved my immediate problem by casting to geometry.
It is, however, worrrying that such fundamental errors exist in in the
geography functions,as for example,
SELECT ST_Intersects('POINT(-160 -43)'::geography, 'POLYGON((-170 -80, -170 0,
170 0, 170 -80, -170 -80))'::geography)
also returns FALSE, which is not a query on the outer fringe.
Incidently, the same query using && also gives an incorrect result.
SELECT 'POINT(-160 -43)'::geography && 'POLYGON((-170 -80, -170 0, 170 0, 170
-80, -170 -80))'::geography
BTW I'm using PostGIS1.5.
I - Dave
David M. Kidd
Research Associate
Center for Population Biology
Silwood Park Campus
Imperial College London
0207 594 2470
________________________________
From: [email protected]
[mailto:[email protected]] On Behalf Of Paragon
Corporation
Sent: 18 April 2011 17:17
To: 'PostGIS Users Discussion'
Subject: Re: [postgis-users] ST_Intersects on geography
Hmm I didn't realize we use BOOM! in our errors, but I guess we do since I get
the same message in 2.0 and 1.5. :)
I know there are issues with the outer fringes when you get into the -180 ...
area which we have bug tickets in place for and patches not yet applied. That
could be one of them
try moving in a bit like 179.5 89 etc.
Unfortunately the guy who deals with these things is incognito at the moment
________________________________
From: [email protected]
[mailto:[email protected]] On Behalf Of Kidd, David
M
Sent: Monday, April 18, 2011 10:25 AM
To: [email protected]
Subject: [postgis-users] ST_Intersects on geography
Hi,
Applogies if the is a stupid newbie question.
I have am writing some some simple point in polygon searches on geographic data
using ST_Intersects, but have been getting some unexpected results;
Searching for a point in the southern hemisphere:
SELECT ST_Intersects('POINT(-160 -43)'::geography, 'POLYGON((-180 -90, -180 0,
180 0, 180 -90, -180 -90))'::geography)
Returns f
Searching for a point in the northern hemisphere:
SELECT ST_Intersects('POINT(160 43)'::geography, 'POLYGON((0 0, 0 90, 180 90,
180 0, 0 0))'::geography)
ERROR: BOOM! Could not generate outside point!
CONTEXT: SQL function "st_intersects" statement 1
********** Error **********
ERROR: BOOM! Could not generate outside point!
SQL state: XX000
Context: SQL function "st_intersects" statement 1
This works though
David M. Kidd
Research Associate
Center for Population Biology
Silwood Park Campus
Imperial College London
0207 594 2470
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