On 3/16/2011 9:39 AM, John Caron wrote:
On 3/15/2011 1:30 PM, [email protected] wrote:
Dear All,
At the nit-picking level, "day" (and "hour" and "minute") are not
necessarily stable units either, because of the occasional appearance
of leap seconds. While this won't be of much concern for many users,
it can be important for precisely timed data.
Hi Tim:
My understanding is that there are some calendars that handle this
better than "standard". the java packages im looking at refers to UTC
and TAI as more accurate possibilities:
http://en.wikipedia.org/wiki/Coordinated_Universal_Time
http://en.wikipedia.org/wiki/International_Atomic_Time
im not clear on the issues, but it seems like we could add those
calendars if needed.
John
I think that this has more implications than i realized.
Suppose we added the UTC_Calendar to CF, which tracks leap seconds etc.
So if one had the time coordinate "days since 1800-01-01" with values =
"0,1,2,3..." and we need the resulting coordinates to be "1800-01-01",
"1800-01-02", "1800-01-03", "1800-01-04",.... which in this calendar
gives an uneven number of seconds between coordinates.
So all timeUnits (except seconds) now mean "increment the calendar
field", not "add x secs to base", that is, its calendar dependent if any
timeUnit implies a fixed number of seconds.
In that case, then fractional values may not make sense(?)
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