182[ISO8601] Re: Clarifications: 220.127.116.11
- Jul 12, 2001On 2001-Jul-12 Paul Hill <goodhill@...> wrote:
> I was reading ISO/TC 154 N 362[2001-Jul-12]
> Ordinal Date
> Section 18.104.22.168 Truncated Version
> Day only in the implied year
> Basic format: -DDD EXAMPLE -102
> Extended format: not applicable
> NOTE Logically, the representation should be [--DDD], but the
> first hyphen is superfluous and, therefore, it has been omitted.
> If I understand this correctly, they are referring to the
> "not applicable" Extended format which the standard has left out.
> The first - would be the missing (i.e. truncated) year the
> second would be the separator dash between the year and the day.
> Do I understand the intent of the dashes and why "the
> representation should be [--DDD]"?
> Also, to where or whom do I send simple typo corrections?
The ISO/TC 154 N 362 [PDF] document to which you refer is the
final draft version of the ISO 8601:2000 standard. The published
version of ISO 8601:2000 is not available online, but the draft
(from only four days previously) can still be downloaded from:
This is for other people reading this, who may wish to get their
own copy of this document. There are several minor typos, and
some formatting problems in this draft document. I do not know
if any of those have been corrected in the published version.
To answer your question: They are not referring to the Extended
format. They are indeed referring, correctly, to the Basic format.
The hyphen in this application is NOT a separator, it replaces
missing data elements. They used to make a distinction between
'Century' and 'Year', referring to 'CCYY'. When referring to a
two digit year, a leading hyphen is supposed to be used. So,
'-99' was Year 99 in the current 'Century'. Therefore, when
specifying only the day of the year, --DDD is the correct form;
there are two missing elements, the 'Century' and the 'Year'.
In the Basic Format, all hyphens are in the place of any
However, because 'DDD' has to be the day of the year, it is the
only three digit element that there is, then this makes it easier
to just use '-DDD', for this, rather than the more technically
correct '--DDD' representation. That is what the note means.
In ISO 8601:2000 they have dropped the term 'Century' because,
for example, the Year 2001, has a 'CC' of '20' but is clearly
in Century '21' in common parlance. ISO 8601:1988 used 'CCYY',
but the new ISO 8601:2000 uses only 'YYYY' with the option to
use more than four digits if required. I prefer 'YYYY' to 'CCYY'.
I am not sure if the '-YY' two-digit year stuff is still in
the ISO 8601:2000 version or not. I will check this later.
I have not got a copy of the standard here to refer to at the
moment, but I am reasonably sure that what I have said above is
correct. Perhaps other people on this list may like to add
further comments and corrections to what I have said.
Corrections have to go via your national standards body, and
you usually have to be a 'member'. ISO do not take comments
directly from 'the public'. This is not a typo, in my opinion.
You could try writing to the person who wrote the message
shown in the web page I quoted above, or to Louis Visser, at
NNI, who was in charge of the update to the ISO 8601 standard.
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