Hello-
I don't think I have any standing to vote on CF matters, but I just wanted to
say that I quite agree with Steve Hankin's viewpoint. I personally like
ISO8601 date/time strings for text display, but agree that under-the-hood
encodings such as CF "days since T" or Unix "seconds since the Epoch" are ideal.
When CF says "days since T" I feel that "T" should be expressed in ISO8601 (it
often is; I don't know if that's a requirement).
Regarding the precision or accuracy of time, perhaps you already know that
ISO8601 provides a means of expressing a time interval. This could be the
syntax used to express temporal uncertainty in metadata. The syntax is
PyYmMdDThHmMsS
where:
P stands for 'period';
T separates date from time components (if any);
Y, M, D, H, M, S are suffixes meaning Years, Months, &c
(the second M(inutes) can only occur after T so it is
distinguishable from M[onths]);
y, m, d, h, m, are integers;
s is integer or real;
unneeded components can be omitted.
Example: P7DT6H30M means an interval of 7 days, 6 hours, 30 minutes.
-Jeff DLB
Steve Hankin wrote:
> Since this email thread already contains an element of informal voting
> I'll cast my ballot: CF is a better standard *WITHOUT *admitting ISO
> date strings as an encoding for time coordinates.
> [...]
> None of this is a comment on the utility of ISO date/time strings as
> metadata. There are appropriate uses of ISO date/time strings in CF as
> non-coordinate variables and attributes. The NO vote is in regard to
> their use as CF coordinates.
--
Jeff de La Beaujardi?re, PhD
U.S. National Oceanic and Atmospheric Administration (NOAA)
Sr Systems Architect, Integrated Ocean Observing System (IOOS) Program Office
1100 Wayne Ave #1225, Silver Spring MD 20910 USA
+1 301 427 2427
Jeff.deLaBeaujardiere at noaa.gov
Received on Fri Oct 22 2010 - 15:01:37 BST
