W3C home > Mailing lists > Public > public-vocabs@w3.org > February 2015

Re: Circa. dates

From: Karen Coyle <kcoyle@kcoyle.net>
Date: Sat, 28 Feb 2015 14:24:31 -0800
Message-ID: <54F2401F.8050008@kcoyle.net>
To: public-vocabs@w3.org
Also note that some of the "circa dates" attempt to narrow down the date 
to a century or a decade. In library data this is done with "19uu" or 
"196u" with "u" standing for unknown, of course. In one system we 
indexed these as ranges, e.g. 1900-1999, 1960-1969, which worked for our 
date search algorithm but is of course is ambiguous (is it really a 
range? or is it an approximation?). Another interesting date that 
appears in archives is the "flourished" date -- this gets used for 
writers and artists for whom the time period of their work is known but 
their bio information has not be recorded for the ages.

That said, I'm wondering what the use case is for defining these dates 
as "circa" or "flourished" in schema.org. One of the really useful 
things about schema.org is that you keep the display form, in this case 
"c. 1765", for human consumption, but can also include a coded form that 
is actionable. Question is, what is that action, and is "circa" 
something that the action with act on?

kc

On 2/28/15 9:51 AM, Wallis,Richard wrote:
> Hi all,
>
> With colleagues I have been looking at how we might handle historical
> approximate dates in Schema.org <http://Schema.org>.  The initial
> requirement being to be able to describe an old book or manuscript
> published say in approximately 1765.  A common need in the bibliographic
> world, with the normal string based solution being “circa. 1765”, or “c.
> 1765” - Wikipedia providing some examples
> <http://en.wikipedia.org/wiki/Circa>.
>
> The knee-jerk reaction was to suggest some sort of
> approximateDateCreated property for CreativeWork which would not only
> help us bibliographic folks but also those in museums and galleries with
> similar date approximation needs.
>
> Broadening the analysis it became clear that this need could be
> applicable in most any case where you would expect a Date
> <http://schema.org/Date> in the range of a property.  birthDate,
> deathDate, dateCreated, datePublished, foundingDate, all being all
> potential candidates for Circa style dates.  Rolling things into the
> future you could imagine other examples such as wanting to describe the
> last serviced date of a vehicle being circa 2013.
>
> So how to solve this in a simple, yet generic, way?
>
> We could take advantage of the default "if you haven’t got a specified
> type for a property, a Text is acceptable” pattern in Schema, and just
> put in a text string with a defined format: “c.1765”.
>
> Perhaps a more appropriate solution would be to define a new data type,
> to be added to the range of suitable properties.
>
> My pragmatic (KISS and don’t break stuff) view of this leads me to
> suggest a new data type named ‘circaData’, or maybe 'approximateDate' as
> a subType of Date.  With descriptive information in the Type definition
> explaining why/how you would use it in the use cases I describe above.
>
> This approach would add this important functionality, for those
> describing old stuff, without the need for major upheaval across the
> vocabulary, and would at least default to a date for those that do not
> care or look for such approximation aspect of dates.
>
> ~Richard
>

-- 
Karen Coyle
kcoyle@kcoyle.net http://kcoyle.net
m: 1-510-435-8234
skype: kcoylenet/+1-510-984-3600
Received on Saturday, 28 February 2015 22:25:09 UTC

This archive was generated by hypermail 2.3.1 : Saturday, 28 February 2015 22:25:10 UTC