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w3c/ogc sdw wg time ISSUES

From: Little, Chris <chris.little@metoffice.gov.uk>
Date: Wed, 8 Mar 2017 18:12:25 +0000
To: "Ed Parsons (eparsons@google.com)" <eparsons@google.com>, Kerry Taylor <kerry.taylor@anu.edu.au>
CC: "Simon.Cox@csiro.au" <Simon.Cox@csiro.au>, "public-sdw-wg@w3.org" <public-sdw-wg@w3.org>
Message-ID: <3DAD8A5A545D7644A066C4F2E82072883E2AFBA3@EXXCMPD1DAG4.cmpd1.metoffice.gov.uk>
Dear All,

Having been away for various reasons, now getting back up to speed on the Time Ontology, and I am happy with all of the changes that Simon has made, though I must admit, some of the details of Turtle/OWL DL2 etc are beyond me.

I believe that the latest draft (which I am having difficulty in seeing today, either from Firefox on a corporate Windows laptop, or Safari on an iOS9 device) we have addressed some fundamental problems:

1. Non-Gregorian calendars can be supported, with or without leap seconds, funny months, weeks, intercalated days, or even other planets.

2. Disentangled to some extent the confusion caused by using calendar style notations as coordinate systems (like ISO8601 e.g. 2017-03-08T17:16:00.0Z and entities like dateTime). These calendars are useful for attributes or properties but have the attendant problems of assuming durations are well-defined rather than dependant on heuristic algorithms. Coordinate Reference Systems generally should only have a single unit of measure on each axis. This work parallels other activities in OGC/ISO addressing the ISO19111 revision.

I have found my actions (UCL/trss and I18N) and chasing them. Happy to label Unix as Posix, but will disagree with John Cowan about Posix time being a count of seconds - we just to be pedantic about which second.

I think we probably do need a paragraph about leap seconds and intercalation. I can write it.

I agree the Time Zone issue is problematic, but the purpose of the ontology is not to duplicate IANA or anyone else's  scheme.

Chris

 


Chris Little
Co-Chair, OGC Meteorology & Oceanography Domain Working Group

IT Fellow - Operational Infrastructures
Met Office  FitzRoy Road  Exeter  Devon  EX1 3PB  United Kingdom
Tel: +44(0)1392 886278  Fax: +44(0)1392 885681  Mobile: +44(0)7753 880514
E-mail: chris.little@metoffice.gov.uk  http://www.metoffice.gov.uk


I am normally at work Tuesday, Wednesday and Thursday each week



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