Hi Richard, This echoes a discussion in BODC this afternoon and a thought I had some while ago in that having terms inherit the version number of the list in which they reside was not the best of ideas. However, we concluded that maintenance of list versions was a good idea, particularly if the list governance permits deprecation.
I'm not aware of anybody maintaining version numbers at the term level for the Standard Names. Establishing them retrospectively wouldn't be a pleasant task and I don't think there's anything to be gained from their introduction from this point onwards. Cheers, Roy. -----Original Message----- From: cf-metadata-boun...@cgd.ucar.edu [mailto:cf-metadata-boun...@cgd.ucar.edu] On Behalf Of Hattersley, Richard Sent: 17 December 2010 16:13 To: John Graybeal; Jeff deLaBeaujardiere Cc: cf-metadata@cgd.ucar.edu Subject: Re: [CF-metadata] Web reference to a standard name? It would seem that the two conflicting requirements, which I'll caricature as "rigorous version control" and "pragmatic usability", could go some way to being reconciled by using term-specific version numbers. Instead of: <some_prefix>/<cf_vocab_number>/<term> (e.g. .../P071/16/CFSN0023) Or: <some_prefix>/<term> (e.g. .../parameter/air_temperature) You have: <some_prefix>/<term>/<term_version> Where the term_version is only updated when the definition of the term changes - not when a release of the standard name table occurs. Thus avoiding the proliferation of identifiers. This would still leave a discussion on what constitutes a "change", as it's quite possible one may wish to allow minor edits (eg. spelling corrections) for pragmatic reasons. Richard Hattersley AVD Expert Software Developer Met Office FitzRoy Road Exeter Devon EX1 3PB United Kingdom Tel: +44 (0)1392 885702 Fax: +44 (0)1392 885681 Email: richard.hatters...@metoffice.gov.uk Website: www.metoffice.gov.uk -----Original Message----- From: cf-metadata-boun...@cgd.ucar.edu [mailto:cf-metadata-boun...@cgd.ucar.edu] On Behalf Of John Graybeal Sent: 17 December 2010 00:16 To: Jeff deLaBeaujardiere Cc: cf-metadata@cgd.ucar.edu Subject: Re: [CF-metadata] Web reference to a standard name? I offer my two cents on versioned terms, prompted by the 'absolutely right' phrasing :->. I am firmly straddling the fence on this question. There are multiple science users and many technical opinions that say not having versions is absolutely wrong. The circumstances that could make 'current' *not* what you want include: - you need to understand what definition (or other statements) was in effect when the tag was applied - you want to understand the transitions that the definition (or other statements) has undergone over time - the meaning of a term actually is significantly different than it used to be - additional meanings are associated with a term (e.g., an acronym is repurposed by another organization) at a later date I believe the last happens much more often than your confidence suggest -- perhaps especially in emerging fields or those that are newly developing documented vocabularies, extremely advanced or subjective fields, and concepts that get 'culturally adopted', e.g., turned into a pejorative (slang (that last not our problem, for the most part). I don't see how the exclusive use of non-versioned terms supports these situations. So while I appreciate the motivations for not including versions, I think versions have to be offered by the system, and ideally should be used where unique persistent identifiers are required. John On Dec 16, 2010, at 13:08, Jeff deLaBeaujardiere wrote: > Actually, my recollection is that EPSG & OGC proposed to include version numbers, and several of us argued against it and managed to convince them. I would have to dig up old emails to find out for certain who was in which camp, however. > > Regards, > Jeff DLB > > On 2010-12-16 15:57, Lowry, Roy K. wrote: >> Hi Jeff, >> >> It's interesting to see the difference of opinion between the standards developers (the idea of version number in URI came from the OGC URN specification: interesting how EPSG came to a different conclusion) and those who have to live with the consequences. The more I think about it, the more I think you and Benno are absolutely right. >> >> Cheers, Roy. >> ________________________________________ >> From: cf-metadata-boun...@cgd.ucar.edu >> [cf-metadata-boun...@cgd.ucar.edu] On Behalf Of Jeff deLaBeaujardiere >> [jeff.delabeaujardi...@noaa.gov] >> Sent: 16 December 2010 19:40 >> To: John Graybeal >> Cc: cf-metadata@cgd.ucar.edu >> Subject: Re: [CF-metadata] Web reference to a standard name? >> >> On 2010-12-14 12:56, John Graybeal wrote: >>> Just to be crystal clear, the places where you have '16' could also have 'current' (if I understand correctly what Roy was saying about their server), and the mmisw one could also be served with a particular version ID (analogous to the NERC example). >> >> I think it is of the utmost importance to have a URI that does not >> include a version number and always provides the latest answer. >> Otherwise you have a proliferation of identifiers mean the same thing >> but appear to change every time the overall vocabulary is updated. You can also have a version-specific entry if desired. >> >> There were similar discussions regarding identifiers for coordinate >> reference system identifiers from EPSG (European Petroleum Survey >> Group), and it was fortunately recognized that a version-less URI was essential. >> >> -Jeff >> >> >> _______________________________________________ >> CF-metadata mailing list >> CF-metadata@cgd.ucar.edu >> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata-- >> This message (and any attachments) is for the recipient only NERC is >> subject to the Freedom of Information Act 2000 and the contents of >> this email and any reply you make may be disclosed by NERC unless it >> is exempt from release under the Act. Any material supplied to NERC >> may be stored in an electronic records management system. > _______________________________________________ > CF-metadata mailing list > CF-metadata@cgd.ucar.edu > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata John Graybeal <mailto:jgrayb...@ucsd.edu> phone: 858-534-2162 System Development Manager Ocean Observatories Initiative Cyberinfrastructure Project: http://ci.oceanobservatories.org Marine Metadata Interoperability Project: http://marinemetadata.org _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata -- This message (and any attachments) is for the recipient only NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system. _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata