Dear all,
interesting discussion. From the point of view of an outsider (not dealing
with ocean data ;-) there are two issues which still aren't entirely clear to
me:
1) as Steve Hankin wrote, this variable has a potential to deflect from the
actual physical quantity, which is expressed in the "time" dimension variable.
This is no harm as such, but I am wondering if we shouldn't make this relation
clearer, for example by defining the standard_name as
"time_expressed_as_iso8601", or perhaps more precisely
"datetime_expressed_as_iso8601". (Yes, Jonathan, I can see that this could open
a backdoor towards replacing the numerical time construct by a string variable
eventually...).
2) I agree with a few others that human readability should not be a criterion
as such. If you think this through, then we would have to go back to ascii for
everything (then I will look for a new job). I do, however, appreciate the need
for documenting, i.e. preserving original datetime labels as they may have been
sent for example from buoys. But in this sense, this variable only serves as a
label and could in principle be some different entity such as a UUID or a
random number. This has a very important consequence, because it implies that
this datetime information should never be used by any software for processing
(date)time information.
I hope you have detected that 1 and 2 are almost orthogonal to each other. I
have a feeling that you lean towards 2 with your standard_name proposal, but
that you have a secret wish to actually use datetime_iso8601 as a "real" time
variable. This makes me slightly worried, unless there is a formal discussion
to extend the convention via a track ticket.
Another issue is the default time zone. I couldn't quite follow whether the
default will be "local" or "UT" in the end. If "UT" which makes a lot more
sense in terms of "CF interoperability", this would break the ISO standard.
This can of course be overcome by a community profile, but then there should
also be a clear reference to this standard (a namespace attribute?).
Best regards,
Martin
PD Dr. Martin G. Schultz
IEK-8, Forschungszentrum Jülich
D-52425 Jülich
Ph: +49 2461 61 2831
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Forschungszentrum Juelich GmbH
52425 Juelich
Sitz der Gesellschaft: Juelich
Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498
Vorsitzender des Aufsichtsrats: MinDir Dr. Karl Eugen Huthmacher
Geschaeftsfuehrung: Prof. Dr. Achim Bachem (Vorsitzender),
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Prof. Dr. Sebastian M. Schmidt
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