[CF-metadata] fuzzy time units

From: John Caron <caron>
Date: Fri, 18 Mar 2011 13:34:40 -0600

On 3/18/2011 9:17 AM, Bob Simons wrote:
> On 3/17/2011 5:20 PM, cf-metadata-request at cgd.ucar.edu wrote:
>> From my POV, the problem is that users need more expressiveness
>> for the
>> calendar time. I certainly do. For yearly data, "years since base_date
>> by calendar field" (or whatever) is consistent, simple and elegant.
>
> UDUNITS defines year, sidereal_year, tropical_year, common_year,
> leap_year, Julian_year, gregorian_year, and work_year.
> Couldn't UDUNITS and CF also define "calendar_year" and
> "calendar_month", which wouldn't have fixed single values but which
> would have precise definitions which could be used in calendar
> calculations? (Also, their variables would be restricted to integer
> values.)
> That would allow the current CF definition of "months_since" and
> "years_since" to stand unchanged, and add a way to specify calendar
> months or years.
> Wouldn't that be consistent, simpler, and more elegant?

Hi Bob:

this seems reasonable to me. it implies that hours and days remain a
fixed length in seconds for all calendars. Im thinking maybe thats ok -
anyone who is worried about leap seconds should encode the time and time
duration of their data in seconds. they dont really want to count on
another library to get this right.

anyway, i like this idea. Im taking the liberty of forwarding it to the
group discussion.
Received on Fri Mar 18 2011 - 13:34:40 GMT