[postgis-users] regress_ogc. failed

[Michael Fuhr]

On Wed, Sep 13, 2006 at 08:22:15AM +0200, Heinz-Josef Lcking wrote:
> When does postgis / the user need regress_ogc ?

regress_ogc is a regression test; it submits a query and compares
the result to the expected result to check for bugs.  In this case
the query is

  SELECT 'unite_garray',
	 astext(unite_garray(geom_accum('{POINT(0 0)}', 'POINT(2 3)')));

The regression test expects

  unite_garray|MULTIPOINT(2 3,0 0)

With GEOS 2.2.3 I get the expected result; with GEOS 3.0.0rc1 I get

  unite_garray|MULTIPOINT(0 0,2 3)

These geometries are spatially equal; only their point order differs.
According to the OpenGIS Simple Features Specification, Section
2.1.4, the elements of a MultiPoint "are not connected or ordered,"
which is probably why strk wondered if the regression test should
be equals('MULTIPOINT(2 3,0 0)', ...) instead of checking for a
specific point order.

-- 
Michael Fuhr