Sorry I misspoke. A ‘Z’ is required to identify the ISO8601 time stamp as GMT time. So I do agree with point #2 below….but adding a ‘Z’ seems to break the CF convention up to this point.
From: JPL <edward.m.armstr...@jpl.nasa.gov<mailto:edward.m.armstr...@jpl.nasa.gov>> Date: Thursday, September 22, 2016 at 2:13 PM To: Chris Barker <chris.bar...@noaa.gov<mailto:chris.bar...@noaa.gov>>, Jonathan Gregory <j.m.greg...@reading.ac.uk<mailto:j.m.greg...@reading.ac.uk>> Cc: "cf-metadata@cgd.ucar.edu<mailto:cf-metadata@cgd.ucar.edu>" <cf-metadata@cgd.ucar.edu<mailto:cf-metadata@cgd.ucar.edu>> Subject: Re: [CF-metadata] Temporal nitpicks. Was: CF-metadata Digest, Vol 161, Issue 3 I think #1 is a great idea as it has been a practice in a number of satellite missions. #2 I am not too fond of. Best practice says that when offset is not specified implicitly GMT must be assumed. So I think specifying a ‘Z’ in ISO time stamp is only necessary when specifying a non zero offset. From: CF-metadata <cf-metadata-boun...@cgd.ucar.edu<mailto:cf-metadata-boun...@cgd.ucar.edu>> on behalf of Chris Barker <chris.bar...@noaa.gov<mailto:chris.bar...@noaa.gov>> Date: Thursday, September 22, 2016 at 8:45 AM To: Jonathan Gregory <j.m.greg...@reading.ac.uk<mailto:j.m.greg...@reading.ac.uk>> Cc: "cf-metadata@cgd.ucar.edu<mailto:cf-metadata@cgd.ucar.edu>" <cf-metadata@cgd.ucar.edu<mailto:cf-metadata@cgd.ucar.edu>> Subject: Re: [CF-metadata] Temporal nitpicks. Was: CF-metadata Digest, Vol 161, Issue 3 On Thu, Sep 22, 2016 at 5:53 AM, Jonathan Gregory <j.m.greg...@reading.ac.uk<mailto:j.m.greg...@reading.ac.uk>> wrote: Dear Chris et al. I may have missed it - are you proposing a change or a clarification to the text of the CF standard document? yes and no: Yes, in that I'm proposing that somthing be chaged in the docuemnt -- really about recommendations and example,s rather than chanign anything about what it allowed. No, in that I (or anyone else) has not proposed any particular text. But if there seems to be a consensus that it would be good ti updated the docs to make these recommendaiont,s than hopefully someone will suggest actual text. (I'm short of roundtoits at the moment). I think these are the ideas: 1) recommend ISO-8601 compliant time strings 2) recommend that an offset (or 'Z') always be provided in a time string. 3) Have all examples conform to the above. Does anyone this these are NOT good ideas? NOTE: as I understand it, ISO-8601 time strings are acceptable to UDUnits, and thus this would not be a change to the standard in any way -- simply recommendations of good practice. TBD: According to wikipedia, ISO requires a "T" in between teh date and time, but then says " It is permitted to omit the 'T' character by mutual agreement" so do we want to recommend one or the other? I think UDUnits does not use a T but maybe it will accept it. (the Python netcdf4 lib added support for the optional "T" a couple years ago -- no idea about any other parsing libs. -CHB Best wishes and thanks Jonathan ----- Forwarded message from Chris Barker <chris.bar...@noaa.gov<mailto:chris.bar...@noaa.gov>> ----- > Date: Wed, 21 Sep 2016 12:52:48 -0700 > From: Chris Barker <chris.bar...@noaa.gov<mailto:chris.bar...@noaa.gov>> > To: Nan Galbraith <ngalbra...@whoi.edu<mailto:ngalbra...@whoi.edu>> > CC: "cf-metadata@cgd.ucar.edu<mailto:cf-metadata@cgd.ucar.edu>" > <cf-metadata@cgd.ucar.edu<mailto:cf-metadata@cgd.ucar.edu>> > Subject: Re: [CF-metadata] Temporal nitpicks. Was: CF-metadata Digest, Vol > 161, Issue 3 > > On Tue, Sep 20, 2016 at 5:45 AM, Nan Galbraith > <ngalbra...@whoi.edu<mailto:ngalbra...@whoi.edu>> wrote: > > > Can we recommend the use of ISO-compatible date strings, with > > the caveat that time zone should always be included? > > > > Yes, we really should do that (though it's an offset that is specified, not > a time zone) > > It's unfortunate that ISO defaults to local time, and that seems to be > > non-negotiable. > > > > yup :-( > > This is what we use in the OceanSITES implementation of CF. Obviously, > > it won't solve everyone's needs, > > > I'm trying to see whos needs it wouldn't suit folks may well want local > time, rather than UTC, but having it be unspecified does no one any good. > > and specifying times in "true" local time, with DST baked in is simply a > nightmare for everyone --- it really, really should be discouraged! > > -CHB > > > -- > > Christopher Barker, Ph.D. > Oceanographer > > Emergency Response Division > NOAA/NOS/OR&R (206) 526-6959<tel:%28206%29%20526-6959> voice > 7600 Sand Point Way NE (206) 526-6329<tel:%28206%29%20526-6329> fax > Seattle, WA 98115 (206) 526-6317<tel:%28206%29%20526-6317> main > reception > > chris.bar...@noaa.gov<mailto:chris.bar...@noaa.gov> > _______________________________________________ > CF-metadata mailing list > CF-metadata@cgd.ucar.edu<mailto:CF-metadata@cgd.ucar.edu> > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu<mailto:CF-metadata@cgd.ucar.edu> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata -- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception chris.bar...@noaa.gov<mailto:chris.bar...@noaa.gov>
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