[postgis-users] RE: [postgis-devel] GML output

[Darko Androsevic]

Martin,

The prefix is NOT the namespace. The prefix is arbitrary. What counts is the
URI. The use of prefix gml: is only convention and is  meaningless without
the namespace binding. The binding is declared with xmlns attribute.
See the "Namspaces in XML (World Wide Web Consortium 14-January-1999)":
http://www.w3.org/TR/REC-xml-names/

Regarding 'prefixes', see section "3. Qualified Names", the very last
paragraph, reproduced below:

"Note that the prefix functions only as a placeholder for a namespace name.
Applications should use the namespace name, not the prefix, in constructing
names whose scope extends beyond the containing document"




GML2.x has been removed from the list of OGC specs
http://www.opengeospatial.org/specs/?page=specs
Its status is D-IS (Deprecated Implementation Specification). Given this,
all future development should be based on GML3.x.


Thanks,
Darko



-----Original Message-----
From: Martin Daly [mailto:Martin.Daly at cadcorp.com]
Sent: Friday, September 24, 2004 1:29 AM
To: Darko Androsevic; PostGIS Users Discussion
Cc: Frank Warmerdam; PostGIS Development Discussion; Paul Ramsey
Subject: RE: [postgis-users] RE: [postgis-devel] GML output


Darko,

> The namespace prefix is arbitrary--it could be "tns". What's 
> essential is that the prefix is bound to the correct namespace:
> 
> <tns:Polygon xmlns:tns="http://www.opengis.net/gml">
> ...
> </tns:Polygon>

As I said originally "There are all sorts of ways to cope with
namespaces".  However, the AsGML() function works in isolation, only
producing the geometry property of a feature.  It has no context within
which to work.  Using the "gml:" namespace prefix removes the need for
an extra parameter, and probably improves interoperability.

> GML 2.x is history.

Your organisation is entitled to an opinion, but that doesn't make it
the truth.

Regards,
Martin

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