Hi Michael et al.,
For information only, but in the hope that it may help inform this
debate, the Open Geospatial Consortium (OGC) has produced a best
practice document that describes a standard mechanism for using URNs to
reference various abstract concepts and resources, especially those
relating to coordinate reference systems (e.g. datums, ellipsoids, prime
meridians, etc). The URNs follow the format
"urn:ogc:def:crs:EPSG:6.3:26986" (for a CRS defined in the EPSG
codespace, in this example).
The document is called "Definition identifier URNs in the OGC
namespace". It can be obtained at the following URL:
http://www.opengeospatial.org/standards/bp
It might provide some useful pointers and/or guidance.
Regards,
Phil
On Wed, 2007-03-21 at 15:07 -0700, Godin, Michael wrote:
> Luis, Bryan, et al.,
>
> This discussion was tabled last year pending at arrival of a cf domain name. Now that the domain cfconventions.org exists, perhaps can we revisit defining namespaces for cf, such as:
>
> urn:org:cfconventions:standard_name:entry
> urn:org:cfconventions:standard_name:canonical_units
>
> and then for a particular entry we can uniquely identify it by saying:
>
> urn:org:cfconventions:standard_name:entry#air_density
> urn:org:cfconventions:standard_name:canonical_units#kg.m-3
>
> where the canonical units simply have "." substituted for " " (as implemented in the output of ucar.units.Unit.getDerivedUnit();
>
> What would it take to make such a set of namespaces official?
>
> Thanks, Mike
>
> _____________________________________________
> Michael A. Godin
> Software Engineer
> Monterey Bay Aquarium Research Institute
> http://www.mbari.org
>
> -----Original Message-----
> From: cf-metadata-bounces at cgd.ucar.edu [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Bryan Lawrence
> Sent: Monday, April 03, 2006 7:17 AM
> To: cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] unique identifiers
>
>
> Hi Luis
>
> Funny you should suggest this .. .we're on the same path too.
>
> Suffice to say, if you can live with your temporary name space, we'll be able to propose something later this year ... (with a cf domain rather than ncar).
>
> Cheers
> Bryan
>
> On Thursday 30 March 2006 19:00, Luis Bermudez wrote:
> > Dear All,
> >
> > We need unique identifiers so we can better describe the information
> > we are sending in XML files. This is to support Feature catalogues,
> > ISO -19115, SensorML etc.
> >
> > Is there an official namespace for CF standard names ?
> >
> > If not then we could we create a namespace like the following:
> >
> > urn:edu:ucar:cf:standard_name:entry
> > urn:edu:ucar:cf:standard_name:canonical_units
> >
> > and then for a particular entry we can uniquely identify it by saying:
> >
> > - urn:edu:ucar:cf:standard_name:entry#air_density
> > - urn:edu:ucar:cf:standard_name:entry#kg_m-3 (needs a little bit of
> > massage)
> >
> > At MMI we are using a temporal namespace (http://marinemetadata.org/
> > 2005/02/cf), but we are looking forward to have a synchronize ontology
> > with your publish XML file, so we can have real time mappings with
> > other standard dictionaries.
> >
> >
> > Cheers,
> >
> > Luis
> >
> >
> > ---------------------------------------
> > Luis Bermudez Ph.D.
> > Software Engineer
> > MMI Liaison - http://marinemetadata.org bermudez at mbari.org
> > Tel: (831) 775-1929
> > Monterey Bay Aquarium Research Institute
>
> --
> Bryan Lawrence
> Director of Environmental Archival and Associated Research Head of the NCAS/British Atmospheric Data Centre CCLRC, Rutherford Appleton Laboratory Phone +44 1235 445012; Fax ... 5848; Web: home.badc.rl.ac.uk/lawrence _______________________________________________
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