[postgis-devel] [PostGIS] #944: typmod support for PostGIS geometry

PostGIS trac at osgeo.org
Fri May 13 04:13:15 PDT 2011

#944: typmod support for PostGIS geometry
 Reporter:  robe         |       Owner:  pramsey      
     Type:  enhancement  |      Status:  new          
 Priority:  medium       |   Milestone:  PostGIS 2.0.0
Component:  postgis      |     Version:  trunk        
 Keywords:               |  

Comment(by robe):


 AddGeometryColumn is an OGC standard but seems to not be mentioned at all
 in the SQL/MM specs and in the OGC it does call it a table that needs
 registration. Same for DropGeometryColumn.

 The SQL/MM spec (seciton ISO/IEC CD 13249-3:200x()  I am looking at
 doesn't even have geometry_columns but talks about
 ST_GEOMETRY_COLUMNS (which is a view (living in ST_Information_Schema)
 "which lists the columns whose declared type is ST_Geometry
 or one of its subtypes;" ).  Thus my suggestion that our pure solution
 that only looks at the system catalogs be called ST_Geometry_Columns and
 that geometry_columns be a hybrid.

 One additional note.  Given the amount of back and forth we have had on
 this topic, I think this one calls for an RFC of how exactly we propose to
 change this. I think typmod is great and we should go ahead with that so
 its really the question of how to manage the metadata. To me this is a
 fundamental change in the way people operate and the way we will be
 recommending people to operate so it needs more consideration and

 I also think we should bring this up to discussion in regular postgis
 users group
 to get a better population metric of its impact and people's thoughts on
 the matter (particularly people managing viewers and other tools that use
 postgis).  I'm only guessing based on my personal use cases, but I'm sure
 there are a lot more we haven't thought about.

 strk also mentioned that INSPIRE would like to keep track of additional
 information beyond what is allowed in geometry_columns and making this a
 system catalog only query view will make that worse.  True its a side
 issue, but thought I would bring it up as a topic for discussion.

Ticket URL: <http://trac.osgeo.org/postgis/ticket/944#comment:15>
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