A time interval is defined in ISO DIS 8601 Part 1, 2.1.3, as “part of the time axis limited by two instants.” In Part 2, 4.4, it’s a “start and end date separated by ‘/’.”
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Gary, thanks for the summary of some high points. I have to admit I don’t understand what is meant by “time intervals.” Can you give us a rough idea of it?
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I took the thing home last night and made some notes. I'm sure this list isn't comprehensive, and may in fact not even be fully accurate …
But first an observation: the thing we're presented with is a draft. Despite the language about being superseded (however spelled), since this is only a *draft* and barring specific instruction from PCC to the contrary, I believe we should continue to use the current versions of 8601 and EDTF in the manner to which we've become accustomed, including the existing code "edtf" in subfield $2 when appropriate. Others may have a different opinion on this issue.
Anyway, it looks to me like draft Part 2 makes possible the same kinds of things we've been doing in the past with EDTF, although the manner in which those things are expressed may be different; and there are also some things that appear to me to be new. Since the implementation of the last stage of the conversion of LC/NACO Authority File is several years behind schedule, I will not comment on the possibility that EDTF expressions might automatically be converted into the newer form. Happily, many of the difference between EDTF and Part 2 are in features that are used only rarely in our authority records; so the most expedient thing (once we have an official version of this document) might be to identify those few odd cases and adjust them individually.
4.2: Uncertain and/or approximate date: We are already familiar with the marker "?" used to mean "uncertain" and the marker "~" used to mean "approximate". There is a new marker, "%", which means "both uncertain and approximate." Additionally, at least in Level 2, the markers may appear either to the left or the right of a date or date element, depending on the meaning to be conveyed; this replaces the EDTF mechanism of isolating date elements in parentheses. The "Guidelines" section at the end, if you can either ignore the stray apostrophes or add the missing apostrophes (unclear how to interpret the inconsistency), is illuminating.
4.3: Unspecified: Character "X" is now used instead of "u".
4.4: Enhanced time interval: I think this is a same, but what I think is a simple typographical error in the list following "The following are allowed …" makes this unclear.
4.5: Year exceeding four digits: Character "Y" is now used instead of "y", and "E" instead of "e".
4.6: Significant digits: Character "S" is now used instead of "p"
4.7: The provision for seasons in hemispheres is different, and I believe that the provision for quarters, quadrimesters and semesters is new.
4.10: Decade: I think this is entirely new. Part 1 allows for reduced precision by omitting even numbers of digits, but not (as here) an odd number. (The difference in meaning between "196" and "196X" must be significant, but escapes me at the moment.)
While we're on the subject of reduced precision: I note that EDTF specifically put the use of reduced precision to represent centuries in the "out of scope" bucket, though that practice is defined in the original 8601 (and in the new Part 1). What implications are to be drawn from the utter lack of examples showing century dates in this draft of Part 2?
5: Repeat rules for recurring time intervals: I think this is entirely new
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I looked over the two new documents linked to from that page and found it very difficult to make much of them. Could we get a layman’s summary of the new standards so more of us can understand it?
UAB Lister Hill Library
Would it still require coding, if the "extension" constitutes a variant of the standard? And please, LC, it's "superseded" (sniff sniff).
On Thu, Aug 24, 2017 at 4:14 PM, Ryan Hildebrand <[log in to unmask]> wrote:
On LC’s EDTF page (https://www.loc.gov/standards/datetime/) I just noticed: “The draft specification is to be superceded; EDTF functionality has been integrated into a draft revision of ISO 8601 to be published in 2017 or 2018.”
This is the first I have heard of this, and am afraid I have missed conversations elsewhere on the topic. Are others following the new ISO 8601 draft (and omitting |2 coding in 046)?
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