[postgis-users] Problems with ST_Within in an island of a multipolygon

[Larry Reeder]

Thanks for the response, Sandro.    I've posted a test case on Dropbox
at http://dl.dropbox.com/u/14591732/foo_reload.sql.   This SQL script
will create a table called "foo_reload" with three features.   Here's
my sample session:

#  \i /tmp/foo_reload.sql
[load statements removed]

#  select gid, ST_IsValid(the_geom) from foo_reload;
 gid | st_isvalid
-----+------------
   1 | t
   2 | t
   3 | t
(3 rows)

So, all 3 features are valid.   Good.

#  select ST_Within(ST_GeomFromText('POINT (-115.04252 36.05137)',
-1), the_geom) from foo_reload where gid = 3;
 st_within
-----------
 t
(1 row)

Feature #3 contains my test point.   Good.

#  SELECT gid from foo_reload where ST_Within(ST_GeomFromText('POINT
(-115.04252 36.05137)', -1), the_geom);
 gid
-----
(0 rows)

No features contain my test point.  What????

# delete from foo_reload where gid = 2;
DELETE 1

Deleted feature #2 from my layer.  This is the "water" that surrounds
my multipolygon "island".

# SELECT gid from foo_reload where ST_Within(ST_GeomFromText('POINT
(-115.04252 36.05137)', -1), the_geom);
 gid
-----
   3
(1 row)

Now PostGIS tells me that feature #3 contains the point.  What??


Can anyone else reproduce my problem?


Thanks..............              Larry



On Wed, Mar 23, 2011 at 3:23 PM, Sandro Santilli <strk at keybit.net> wrote:
> On Tue, Mar 22, 2011 at 07:17:26AM -0600, Larry Reeder wrote:
>> Anybody have any ideas on this one?    Do you think I should post it
>> to the developer list?
>
> You might post a testcase, the smallest possible.
>
> --strk;
>
>  ()   Free GIS & Flash consultant/developer
>  /\   http://strk.keybit.net/services.html
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