[postgis-users] TopologyException: side location conflict

[Gopal]

Hi All,

I am running following version of postgis
"POSTGIS="1.1.3" GEOS="2.2.2-CAPI-1.1.0" PROJ="Rel. 4.4.9, 29 Oct 2004"
USE_STATS"
On "PostgreSQL 8.1.4 on i686-pc-mingw32, compiled by GCC gcc.exe (GCC)
3.4.2 (mingw-special)" on windows 2003 server.

I am getting the following error when I try intersection on one row...

NOTICE:  TopologyException: side location conflict
(-0.5693,52.0949,52.0949)
CONTEXT:  PL/pgSQL function "usp_getmetadata" line 39 at for over select
rows

ERROR:  GEOS Intersection() threw an error!
CONTEXT:  PL/pgSQL function "usp_getmetadata" line 39 at for over select
rows 


I've isolated, the row that gives the error, the geometry seems to be
valid (I used the isvalid() function).

Strange thing is the error only occurs, when using SRID 4326, when using
srid 27700 everything is fine

Query in srid 27700 - Runs fine

select intersection(GeometryFromText('POLYGON((496999.999878214
245000.006245037,497999.999876959 245000.006245039,497999.999876987
244000.006245681,496999.999878241 244000.006245684,496999.999878214
245000.006245037))',27700),expand(GeometryFromText('POINT(' ||
496000::text || ' ' || 243000::text || ')',27700),greatest(2000,2000)))

Same query but in srid 4326 - Raises the aforementioned error

select intersection(GeometryFromText('POLYGON((-0.583894391985042
52.0950986609407,-0.569300265955149 52.0949224289699,-0.569587785754047
52.0859336829619,-0.584178981284086 52.0861098582684,-0.583894391985042
52.0950986609407))',4326),transform(expand(GeometryFromText('POINT(' ||
496000::text || ' ' || 243000::text ||
')',27700),greatest(2000,2000)),4326))

I am not quite sure what the error means, or how to handle it in a query
and carry on processing upon encountering it

Any help would be appreciated.

Thanks
Gopal