LISTSERV mailing list manager LISTSERV 16.0

Help for DATETIME Archives


DATETIME Archives

DATETIME Archives


DATETIME@C4VLPLISTSERV01.LOC.GOV


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

DATETIME Home

DATETIME Home

DATETIME  November 2009

DATETIME November 2009

Subject:

BC dates

From:

"Ray Denenberg, Library of Congress" <[log in to unmask]>

Reply-To:

Discussion of the Developing Date/Time Standards <[log in to unmask]>

Date:

Mon, 23 Nov 2009 15:24:44 -0500

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (141 lines)

Thanks for your comments, Colleen.  I've changed the subject line to address 
your question about BC dates.

EDTF does support BC  dates, You can see the following examples at 
http://www.loc.gov/standards/datetime/examples.html:

                   "BC date: -1000-01-01"
                   "-10000-01-01 ( January 1 of the year 10,000 BC)"

In fact, both of these are supported by xs:date  and are thus automatically 
supported by EDTF, which is a superset of xs:date.


Note however,  EDTF does not support non-hyphenated BC dates. For example, 
does not support:

                              -10000101

even though it supports both:

                             -1000-01-01

and:

                           10000101

I.e. DOES support both hyphenated BC dates and non-hyphenated positive 
dates. ("Positive" meaning AD/CE.)

So while xs:date does support BC dates, it supports only the hyphenated 
form - xs:date does not support the non-hyphenated form of date, BC or 
positive. On the other hand, EDTF does support a positive date without 
hyphens, even though xs:date does not. This is an EDTF extension to xs:date. 
The reason why EDTF does not support the hyphenated form of a BC date - and 
this is open for discussion -  is that although there is a use case for 
non-hyphenated positive dates, no use case has been offered for 
non-hyphenated BC dates.


Another limitation, possible of concern to nobody: EDTF does not support 
"Year Zero". This has not been raised as an issue and quite likely will not, 
unless members of scientific communities which use year zero become 
stakeholders in this effort; if that happens we would address this, 
otherwise we would not.  "Year Zero" means the year between 1BC and 1AD. 
For most applications such a year does not exist, 1AD is the year 
immediately following 1BC.  However for certain disciplines, astronomy for 
example, year zero is meaningful. Support of year zero would introduce 
serious complexities (for example, alignment of leap years) and we do not 
plan to address it any further if nobody raises it as a requirement.
-- Ray


----- Original Message ----- 
From: "Colleen R Cahill" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, November 23, 2009 7:02 AM
Subject: Re: [DATETIME] Abstract dates and times


Ray,
   Very good start.  One minor thing; there is a extra "0" in your first 
example (should be 20100202).
   We have been using that date format in the Geography & Map Division 
Scanning Lab for years in a table of administrative metadata because it 
sorted the well and was easy to see groupings.  While good for machines to 
parse, it is also something humans can quickly learn to read.   My only 
question is how will you deal with BC dates?  We have not had to face that 
at our shop.
   The time field is not something we have used, but it makes sense and if 
needed, is the most logical way to display this data.  Those who are more 
familiar with "military" time will have less of a learning curve, but I 
don't foresee anyone being stumped by this.  The "T" in front is great as a 
hint for what the data is all about, since time is rarely displayed as a 
number without some punctuation (i.e. 12:10).

Colleen



Colleen R. Cahill
Digital Conversion Coordinator and
   Recommending Officer for Science Fiction and Fantasy
Geography & Map Division
Library of Congress
4652
202-707-8540

>>> "Ray Denenberg, Library of Congress" <[log in to unmask]> 11/19/2009 10:34 AM 
>>>  >>>
I'll get the discussion started.

See the first proposal on the list at 
http://www.loc.gov/standards/datetime/proposals.html.  (Just because it's 
the first does not mean that these have to be discussed in order. Anyone who 
wishes to initiate a thread on any of these proposals, please do. Please use 
a meaningful subject line, though.)

Please comment on whether the feature discussed below is useful. Would you 
use it? implement it?   Please feel free to say no, it is not useful.

Abstract dates and times.

Thus, where:

               201000202

is February 2, 2010

something like:

              ****0202

would simply mean February 2. (As in "Groundhog Day is February 2".)

I am not suggesting this particular syntax, just using it as an example. I 
suggest we avoid the syntax discussion and focus on the functionality, and 
if it seems that this is a feature worth adopting then talk about syntax. 
Also, holidays with no fixed date, Easter for example, are out of scope for 
this thread, they are part of a different proposal.


Similarly for time.....

So where:

            20090412T133500

means 1335 (1:35 PM),  April 12, 2009


Something like:

                 T133500

would mean 1335  (As in "Sunday day game start times are 1:35 PM".)

(There is a third part to the proposal but let's put that on a separate 
thread.)

--Ray 

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

August 2019
February 2019
December 2018
November 2018
October 2018
January 2018
August 2017
July 2017
June 2017
April 2017
March 2017
February 2017
August 2016
July 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
December 2014
November 2014
March 2014
September 2013
May 2013
February 2013
October 2012
September 2012
August 2012
May 2012
March 2012
December 2011
November 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
February 2010
January 2010
December 2009
November 2009

ATOM RSS1 RSS2



LISTSERV.LOC.GOV

CataList Email List Search Powered by the LISTSERV Email List Manager