[CF-metadata] Non-real-world calendars

From: Dave Allured - NOAA Affiliate <dave.allured>
Date: Mon, 1 Jul 2013 18:12:18 -0600

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
<richard.hattersley at metoffice.gov.uk> 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: richard.hattersley at metoffice.gov.uk Web: www.metoffice.gov.uk
Received on Mon Jul 01 2013 - 18:12:18 BST