Richard, I generally agree with your suggestions. The current wording for (3) year zero is wide open for conflicting interpretation. I would prefer to discuss details in a trac ticket, rather than the general user list, when you feel that you have enough support.
--Dave On Mon, Jul 1, 2013 at 7:26 AM, Hattersley, Richard <[email protected]> wrote: > Hi everyone, > > I'd like to propose a trac ticket or two to clarify the meaning when using > alternative calendars. But before I do that I'd like to check for community > opinion (or even consensus!?) ... > > 1. Time zones should be excluded/banned when using non-real-world calendars. > For example, the statement in section 4.4 of "if the time zone is omitted > the default is UTC" should not apply. > > 2. The "months since" and "years since" semantics for non-real-world > calendars need defining/outlawing. e.g. The UDUNITS definition of a year as > 365.242198781 days makes no sense at all for a 360-day calendar, but in this > particular case a year could be unambiguously defined as 360 days. > > 3. The year-zero semantics for non-real-world calendars need defining. From > section 7.4, "Year 0 may be a valid year in non-real-world calendars". > > I have some further questions concerning real-world calendars, but as with > all things dealing with the real world they are a little more messy so I'll > save them for another post. > > Richard Hattersley > Benevolent Dictator of Iris - a CF library for Python: > www.scitools.org.uk/iris > Met Office FitzRoy Road Exeter Devon EX1 3PB United Kingdom > Tel: +44 (0)1392 885702 > Email: [email protected] Web: www.metoffice.gov.uk _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
