Dear All, I think Chris has hit the nail on the head here. In my view neither the Standard Name nor the units of measure are the way to describe what is in essence the format of a string. So, what other options are there open to us? I can see three alternatives:
1) Use the long name to describe the string format (not just the standard used but the profile) 2) Use the existing calendar attribute 3) Specify a suitable extension to CF to do the job. These are roughly in my order of preference. Cheers, Roy. ________________________________________ From: CF-metadata [[email protected]] On Behalf Of Chris Barker - NOAA Federal [[email protected]] Sent: 27 March 2013 15:56 Cc: [email protected] Subject: Re: [CF-metadata] New standard name: datetime_iso8601 (standard_name or units?) On Wed, Mar 27, 2013 at 8:05 AM, Steve Hankin <[email protected]> wrote: > ISO date-time strings are a way of encoding the physical quantity > that we know as TIME. So TIME is the "right" standard_name for ISO > date-time strings per the definition quoted above. > > Now, it may be that there is a compelling argument to violating the normal > definition of standard_name for the case of ISO date-time strings. Or on > the other hand is it preferable to use the units attribute to indicate the > use of an ISO date-time string? An ISO string for a datetime is not a name (it's still time), but it is not a unit either. What it is is a data type -- more akin to a float or integer -- i.e. a particular way to translate bytes to a value. The bytes are a char array, and the value is the datetime itself. I don't know if thinking about it this way is helpful, as we are building on netcdf, and I don't now that netcdf allows you to define new data types, but food for thought. Also, of course, all the other data types in netcdf (and CF) are direct translations to commonly used binary formats in computers, and this one is not. hmm -- a quick peak at the netcdf4 docs says: "The richer enhanced model supports user-defined types and data structures" So maybe this could be a user defined type? Having said that, I don't support using ISO strings to define datetimes in CF. I understand particular use-cases, like keeping the original time stamp from a data collection system and the like, but then maybe it's really just arbitrary auxiliary text information, in which case maybe we don't need a standard name or custom data types at all. -Chris -- 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 [email protected] _______________________________________________ CF-metadata mailing list [email protected] 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 [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
