Can we recommend the use of ISO-compatible date strings, with
the caveat that time zone should always be included?

It's unfortunate that ISO defaults to local  time, and that seems to be
non-negotiable.

This is what we use in the OceanSITES implementation of CF. Obviously,
it won't solve everyone's needs, but it's perfectly good for in situ data.

Regards - Nan

On 9/15/16 3:10 PM, Chris Barker wrote:
On Thu, Sep 15, 2016 at 5:40 AM, Jim Biard wrote: > > That's a completely valid suggestion. We have to consider >
implications for backwards compatibility. Among other things, UDUNITS > would need to change their convention, since CF follows UDUNITS in > this matter, as with all other units. > > As long as UDUNITS accepts ISO-compliant strings, then we're good. > And it looks like it does. > > There's nothing that says we can't make changes. I was explaining the > "is" as opposed to the "could be" with time units. > > The only change I would suggest at the moment would be to "prefer" > ISO-complienat time strings, and therefore use them in the examples. > > -CHB > > Grace and peace, > > Jim > > > On 9/15/16 7:26 AM, Little, Chris wrote: >> Jim and Chris B, I would like to weigh in here, please? Adhering to >> UDUnits has merits, but once one adopts ISO8601-like notations, as >> there is no way of specifying otherwise, people assume it *is* >> ISO8601 and therefore a string without a time zone marker indicates >> local time (whatever that is - Solar? Mean Solar? Sidereal? >> National legal?) There is work just starting in the OGC/ISO >> pipeline on how to indicate a non-Gregorian calendar using ISO8601 >> like notation, for the WKT communities. Personally, I would >> advocate ISO8601 strict adherence, as most of the recommended best >> practices and profiles, such as RFC3339, are generally strict >> subsets of ISO 8601. Chris >> >> -----Original Message----- From: CF-metadata >> Sent: Wednesday, >> September 14, 2016 10:02 PM >> Subject: CF-metadata Digest, Vol 161, Issue 3 >> >> Today's Topics: >> >> 1. nitpick in time axes example (Chris Barker) 2. Re: nitpick in >> time axes example (Jim Biard) >> >> >> ---------------------------------------------------------------------- >> >> >>
Message: 1
Date: Wed, 14 Sep 2016 12:34:11 -0700 >> From: Chris Barker<chris.bar...@noaa.gov> >> To:
"cf-metadata@cgd.ucar.edu" >> Subject: [CF-metadata] nitpick in time axes example >> >> I see in teh doc: >> >> Example 4.4. Time axis >> >> double time(time) ; time:long_name = "time" ; time:units = "days >> since 1990-1-1 0:0:0" ; >> >> IIUC, ISO 8601 requires two digits for the time pieces [1], so that >> should be: >> >> "days since 1990-1-1 00:00:00" >> >> >> The parser I use isn't picky about this, but maybe some are? >> >> BTW, as it's an example, we should probably throw a time offset on >> there, too: >> >> "days since 1990-1-1 00:00:00Z" >> >> >> or >> >> "days since 1990-1-1 00:00:00+00:00" >> >> >> [1] at least according to wikipedia: >> https://en.wikipedia.org/wiki/ISO_8601#Times >> <https://en.wikipedia.org/wiki/ISO_8601#Times> >> >> >> -Chris


--
*******************************************************
* Nan Galbraith        Information Systems Specialist *
* Upper Ocean Processes Group            Mail Stop 29 *
* Woods Hole Oceanographic Institution                *
* Woods Hole, MA 02543                 (508) 289-2444 *
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