[postgis-users] Problem : Within() incorrectly returns 'false'

[Mark Leslie]

> 
> Are zero length segments one of the conditions picked up by isvalid()?
> 

A quick check:

mleslie=# select isValid('POLYGON((0 0,1 0,1 1,1 1,0 1,0 0))'::geometry);
 isvalid
---------
 t
(1 row)

shows that it is not.
Mark