Dear Steve This isn't the central issue, but I wonder if I have missed your point. I agree that there is a gap in the legal dates in the real-world mixed Julian- Gregorian calendar, but this is just an inconvenient problem of translation, isn't it? There is no discontinuity in real-world time!
1 days since 1582-10-14 = 0 days since 1582-10-25 because in the real-world calendar 14 Oct 1582 is followed by 25 Oct 1582. If you code a time coordinate in "days since 1582-10-1" as 0, 1, 2, 3, ... 22 it should be translated into dates of 1582-10-1, 2, 3, ..., 14, 25, ..., 31. This is what really happened. How could we stamp it out? I note that cal(1) has the date change in Sep 1752, when it happened in England $ cal 9 1752 September 1752 Su Mo Tu We Th Fr Sa 1 2 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 but anyone who works with the dates of real historical events should be aware of the need to put them into the same calendar. Cheers Jonathan ----- Forwarded message from Steve Hankin <steven.c.han...@noaa.gov> ----- > Date: Fri, 14 Dec 2012 15:45:27 -0800 > From: Steve Hankin <steven.c.han...@noaa.gov> > User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:16.0) Gecko/20121026 > Thunderbird/16.0.2 > To: Jonathan Gregory <j.m.greg...@reading.ac.uk> > CC: cf-metadata@cgd.ucar.edu > Subject: Re: [CF-metadata] CF calendars (was: problem with times in PSD > dataset) > > > On 12/14/2012 9:35 AM, Jonathan Gregory wrote: > >Dear Cecilia, Steve et al. > > > >Steve is right that mostly we use the Gregorian calendar. That is what I > >meant > >mostly when I said that the default is the calendar we use. The real world > >is mixed Julian-Gregorian, and I don't think dealing with this calendar is an > >issue only for Renaissance historians. I can't give you examples, but I > >think it is conceivable or likely that at some point people would want to > >record real-world data in CF earlier than the Renaissance, or have already > >done so. For instance, what about astronomical data, such as the dates of > >eclipses. These are real-world events, on precise dates which are translated > >into the mixed Julian-Gregorian calendar. > > Hi Jonathan, > > If scientists somewhere have encoded the dates of these historical > events as data(*) using a mixed Gregorian-Julian calendar Lord help > 'em. Those poor folks have to face an 11 day discontinuity in their > own data, as well as in ours. I'm not meaning to be snarky. I just > want to stamp out this pesky calendar issue. It has been tripping > us up for too many years. > > Your points below are definitely the real guts of the discussion, > but in this email I am addressing just the one single point. I'm > afraid we will never heal ourselves from this virus if we do not > eradicate it from our thinking. > > - Steve > > (*) attaching a date to an historical narrative is different from > using a date as a time coordinate. It's metadata versus data. > ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata