[postgis-users] 3D geometry objects

[Ron Mayer]

I was mildly surprised to see that the Z coordinate doesn't work 
the way I was expecting.  In particular, the Z axis seems to be ignored
when comparing bounding boxes, and geomunion seems to flatten my points.

I don't actually need such features to work, but was kinda surprised to 
see no obvious reference in the postgis manual so it made me wonder if I 
have a configuration problem here.

I am using  postgis-0.8.2 and postgresql-7.4.3 on SuSE 9 and a 
postgis-0.8.2 and postgresql-8.0.0beta2.

Example queries of results that surprised me follow.

  Thanks, 
  Ron

 
fl=# select 'BOX3D(-1 -1 -1, 1 1 -2)'::box3d && 'BOX3D(-1 -1 1, 1 1 2)'::box3d;
 ?column? 
----------
 t
(1 row)

fl=# select intersects('BOX3D(-1 -1 -1, 1 1 -2)'::box3d, 'BOX3D(-1 -1 1, 1 1 2)'::box3d);
 intersects 
------------
 t
(1 row)

fl=# select geomunion(a) from (
      select (GeomFromText('POINT(-1 -1 -1)',-1)) as a
      union  
      select (GeomFromText('POINT(-1 -1 -0)',-1)) as a 
     ) as a;
           geomunion
-------------------------------
 SRID=-1;POINT(-1 -1 1.7e-308)
(1 row)

fl=# select geomunion(a) from (
         select (GeomFromText('POINT(-1 -1 -1)',-1)) as a 
         union 
         select (GeomFromText('POINT(-1 -0 -0)',-1)) as a 
      ) as a;
                     geomunion
---------------------------------------------------
 SRID=-1;MULTIPOINT(-1 -1 1.7e-308,-1 -0 1.7e-308)
(1 row)



########## more version info ###########


fl=# -- [on the windows machine]
fl=# select name,setting,postgis_full_version() from pg_settings where name = 'server_version';
      name      |  setting   |                                        postgis_full_version                                         
----------------+------------+-----------------------------------------------------------------------------------------------------
 server_version | 8.0.0beta2 | POSTGIS="0.8.2" GEOS="2.0.0" PROJ="Rel. 4.4.8, 3 May 2004" USE_STATS DBPROC="0.0.1" RELPROC="0.0.1"
(1 row)

fl=# -- [on the SuSE machine (postgis_full_version doesn't exist)]
fl=#  select name,setting,postgis_version() from pg_settings where name = 'server_version';
      name      | setting |            postgis_version
----------------+---------+---------------------------------------
 server_version | 7.4.3   | 0.8 USE_GEOS=1 USE_PROJ=1 USE_STATS=1