On 24/05/12 12:39, Justin Deoliveira wrote:
> * New srs format
> Currently for wfs 1.1 we use the original srs urn syntax as specified in
> the original version of the wfs 1.1 spec. Which looks like:
>    urn:x-ogc:def:crs:EPSG:4326
> The mandated format has been changed "mid-spec" and now the tests
> mandate that the format look like:
>    urn:ogc:def:crs:EPSG::4326
> Note the "double colon" between the authority and code, that is not a typo.

Correct. This element is for the version of the EPSG database. In 
general, urn:ogc versions are optional (hence the double colon), but OGC 
insist on their inclusion in the case of EPSG: "The “version” part shall 
be included in this case, since the EPSG sometimes deprecates and 
replaces existing definitions." From: "URNs of definitions in ogc 
namespace" (OGC 05-010):
https://portal.opengeospatial.org/files/?artifact_id=8814

I don't like this as it is yet another point of variation to confuse 
clients. I am more than happy to have the version left blank, but this 
might cause cite compliance problems later.

> So... what to do. As I see it we have a few options.
> (1) Update this across the board and just output the new form by default.
> (2) Only use this form when cite compliance is turned on.
> (3) Add this new form as a new possibility for GMLInfo.getSrsNameStyle()
> making it configurable to use the new style, updating the wfs 1.1 cite
> configuration to use the newest version and possibly keeping the default
> configuration using the existing style
> All in all I think (3) is probably the most ideal, but represents the
> most work. (1) is the easiest. Curious to here what people think about
> this one.

(1) may break existing clients.

(2) makes we worry that some users will be stuck with all 
cite-compliance options when they only want one.

I like (3), which is also extensible to support the new HTTP URI form 
(e.g. http://www.opengis.net/def/crs/EPSG/0/4326). You could also add 
support for an OGC URN with EPSG version (e.g. 
urn:ogc:def:crs:EPSG:6.3:4326). I suspect that (3) will put us in a 
position to add new formats almost as fast as OGC can invent them.

Here are two current Jira issues:
https://jira.codehaus.org/browse/GEOT-3581
https://jira.codehaus.org/browse/GEOS-4545

Support in WFS for HTTP URIs like:

http://www.opengis.net/def/crs/EPSG/0/4326

is before the WFS/FES SWG and will likely be included in WFS 2.1. See:
"Allow use of http URIs to identify CRS" (WFS/FES change request 11-152):
https://portal.opengeospatial.org/files/?artifact_id=46445

Whitepaper:
"OGC Identifiers – the case for http URIs" (OGC 10-124r1):
https://portal.opengeospatial.org/files/?artifact_id=39467

HTTP URIs are current OGC policy:
"In June 2010 OGC revised the naming policy to use http URIs to identify 
persistent OGC resources instead of URNs."
http://www.opengeospatial.org/projects/groups/ogcnasc

Youse might also be interested in Simon's recent seminar on controlled 
vocabularies (slides and audio):
https://wiki.csiro.au/display/ARRCSeminars/Delivering+controlled+vocabularies+on+the+web+-+persistent+identifiers+and+the+web+of+things

Simon explains why HTTP URIs are useful because they allow the 
implementation of Tim Berners-Lee's Linked (Open) Data rules, and 
describes some successful patterns for using them.

Kind regards,

-- 
Ben Caradoc-Davies <[email protected]>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

------------------------------------------------------------------------------
Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and 
threat landscape has changed and how IT managers can respond. Discussions 
will include endpoint security, mobile security and the latest in malware 
threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
_______________________________________________
Geoserver-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/geoserver-devel

Reply via email to