"Hostage, John" <[log in to unmask]>:
> One reason for using codes for months and seasons is to represent them in a language-independent way.
To be fair, 2018-21, 2018-81 or 2018-S1 or whatever does not depend on the language. It simply denotes the first season of the year. I argued that this would have to be Northern winter and Southern summer to be internally consistent.
> Seasons can never be as unambiguous.
ISO/DIS 8601-2:2016-12 did not define "season" in sufficient detail, but it can be done.
> If we say spring 2018, that's not the same thing in the Southern Hemisphere as in the Northern Hemisphere.
Obviously; that's why we have numeric dates (and times). ISO 8601 also does not have a way to say "sunrise".
> If we say winter 2018, some people in the Northern Hemisphere mean the season we're in now, while some others (some publications) might mean the season that begins next December.
Calendar weeks also have different definitions. ISO picked a sensible one. In the context of ISO 8601, "first week of the year" or "W01" is not ambiguous. Likewise, "first season of the year" would not be ambiguous.
In other words, ISO 8601-2 must not try to support each and every format already used by serial publications. Foremost, it must be internally consistent. If, for instance, the current, "Winter 2017" issue of a magazine was released 2017-12-01, the next to follow on 2018-03-01, its ISO period could very well still be "2018-S1" (or "2018-21" or "2018-80" <https://listserv.loc.gov/cgi-bin/wa?A2=ind1702&L=DATETIME&P=2589> or whatever).
> As I remember it, the codes 21-24 were chosen for seasons in EDTF because they were already being used in the MARC Format for Holdings Data (https://www.loc.gov/marc/holdings/hd853855.html)
I've never seen this format being mentioned anywhere before in EDTF or ISO documents. It deviates in several other aspects from ISO 8601 and does not seem to care for hemispheric differences or exact definitions of a season at all.
Compatibility with existing formats can be a good argument, unless it violates established principles within the standard or harms its further development. I strongly believe that using -21 through -24 for (astronomic) seasons would do both.
> It seems a bit late to make the codes more mnemonic, especially since that would mean making them more language dependent.
Why would it be too late? ISO 8601-2 has not been published yet. The current -21 = Spring etc. specification depends on cultural traditions that are not valid worldwide. The DIS at Level 2 arguably encodes the same seasons with two different codes 25 = 31, 26 = 32, 27 = 29, 28 = 30.
How does any of the (counter) proposals introduce more language-dependency? Assuming, you don't count letters like "Q" for "quarter" or "S" for "season" (both applicable to equivalent terms in several important languages, incl. English).
I have made a spreadsheet to compare the latest proposal, which started this thread, with mine and the ISO/DIS from late 2016 (since there does not seem to be anything more recent available):