Hi Aleksander,
A question to debate in your trac ticket. Per the CF documentation, the
definition of the standard_name is "/The name used to identify the
physical quantity/"
(
http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.6/cf-conventions.html#standard-name).
It is the 'units' string (together with the netCDF data type) that
describe how that physical quantity is represented as a value in the
binary file.
A standard_name for the physical quantity time already exists, of course
-- it is "time". It is listed as such in the CF standards names table.
So should "datetime_iso8601" be a proposal for a new and recognized
value of the time 'units' attribute, rather than a new standard_name?
This isn't so clear. To start answering it ...
What is the reason that standard names exist? Arguably they are to
guide generic software (including metadata search engines) in their
ability to locate physical quantities in a CF file. In that case it is
standard_name ="time" that should guide the software to the variable;
and units="datetime_iso8601" that will instruct the software on how to
interpret the values it finds there.
- Steve
=====================================================
On 3/19/2013 2:31 PM, Aleksandar Jelenak - NOAA Affiliate wrote:
> Nan,
>
> On Tue, Mar 19, 2013 at 3:08 PM, Nan Galbraith <ngalbraith at whoi.edu> wrote:
>> There seems to be surprisingly broad support for this idea, so I've been
>> re-reading the thread, looking for a reasonable use case. I can't say that
>> I've found any description of why we actually need this - am I missing
>> something?
> I appreciate the frank remark. Honestly, I am surprised that you are
> surprised. It is just a standard name. I have no use for the majority
> of standard names being proposed yet do not question why someone needs
> them. My proposal does not want to break the current convention --
> that's the bottom line.
>
>> Anyway, going back to Aleksandar's original (slightly amended) proposal of
>> Jan 11 just for a moment... I'd like to clarify one detail. As far as I
>> know, ISO 8601 calls for the default time zone to be local, not UTC.
> You are correct. My omission. But before amending the proposal I'd
> like to see if there is a broader support for keeping it as-is.
>
>> Allowing a default, and having that default NOT align
>> with ISO, is just too much to ask. Either we're implementing ISO, or not
> My intention is to be fully ISO8601-compliant.
>
> -Aleksandar
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Received on Tue Mar 19 2013 - 16:19:40 GMT
