Bill makes some interesting points here and I hesitate to remind him that
capability to do almost all of what he describes is present in EAD 2002.
<unitdate> does now have a attribute, datechar, which is a "term
characterizing the nature of dates, such as dates of creation, accumulation,
For <date>, the type attribute is CDATA so one may insert any value you
The question of embedding date strings in <subject> raises several
1. Do we want to add an apparatus into EAD that would mimic the
subdivision codes in MARC? There may be some who have the time to break
this data out into every more granular sub-elements but there is the
question of the utility in union systems of tagging that is employed by only
certain institutions. Those are legitimate questions for ongoing
2. Is the interesting date in the Spanish Civil War example the fact that
the war went from 1936-1938 (I don't think that this is the focus) or that
the contents of the correspondence reflects that time period? If the later
is the case, we need to be able to represent that the time span covered by
the materials falls at least within the 1936-1938 period. I wonder if
embedding this information in a subject heading achieves what we really want
3. If one is going to mess with the DTD for some local reason (a highly
dangerous proposition at best), there are less disruptive ways of achieving
this end without creating the chaos that will occur when such non-standard
records are distributed to other systems, as they invariably will.
From: Bill Landis [mailto:[log in to unmask]]
Sent: Wednesday, June 18, 2003 12:42 PM
To: [log in to unmask]
Subject: Re: searching on dates?
The problem Chris points out is a vexing one. I personally hate to see
<date> and <unitdate> get used willy nilly by archivists around the world,
since it seems to me that it poses a real quandry in the future, especially
in union database settings, trying to figure out what dates to index in a
way that will return meaningful results to an end user, or allow end users
to sort result sets in a meaningful way.
The work that has been going on in the U.S./Canadian CUSTARD project
differentiates between the following, all of which an archivist might wish
to associate with an archival unit being described:
*date(s) of creation
*date(s) of recordkeeping activity
*date(s) of publication, distribution, etc.
*date(s) of reproduction
*date(s) of broadcast
Content (or as Chris characterized them, subject) dates are specifically
excluded from the date element associated with the creation of the unit and
redirected to the Scope and content element. CUSTARD is not dealing with
subject-based access points, but it seems to me that subject/content dates
belong there as well in any system that allows subject-based retrieval (as
Chris notes in his EAD workaround example).
I'd really like to see the next version of EAD open up the TYPE attribute on
<unittitle> to #CDATA, allowing it to function the way TYPE functions in the
<date> element. That way, at least, standards of national practice could be
set for prescribed kinds of <unitdate>s and more clarity could be provided
in the definition of <unitdate> in the tag library as to what should and
shouldn't be included.
I'd also like to see some kind of chronological "subject" subelement added
to those that can be encoded within <controlaccess> to make it legal using
the EAD DTD to do what Chris has done in a workaround. I think this makes
Chris Turner wrote:
> We have had to address this same issue for the LEADERS Project,
> http://www.ucl.ac.uk/leaders-project, and in the process realised that
> was a further issue with EAD and date searching. The only specific dating
> elements in EAD are <unitdate> for date of creation and <date> for a lot
> other things too numerous to list here.
> However for date searching we really need an element to describe the
> coverage date(s). For example George Orwell writes a letter in 1948 which
> describes his experiences in the Spanish Civil War in 1936-38. Clearly
> 1936 -1938 would be useful dates for a user to be able to search on. But
> how to encode it in EAD?
> Our solution is like Matt to 'enhance' EAD, by using the <date> element
> within the <controlaccess> wrapper where other searchable data is encoded.
> We use the 'type' attribute on <date> to specify 'subject', 'creation'
> We also use the standard ISO date notation of '/' to specify a date range
> <date type='subject'>1936/1938</date>
> This enables us to tell our search engine where and how index dates for
> user search and retireval.
> But it looks as if we need an 'official' solution to this from the EAD
> because ad hoc solutions seem to be proliferating.
> Chris Turner
> Senior Research Fellow: Leaders Project
> School of Library, Archive and Information Studies
> University College London
> Gower Street
> London WC1E 6BT
> +44(0)20 7679 7205
> [log in to unmask]
> ----- Original Message -----
> From: "Hillyard, Matthew" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, June 18, 2003 12:40 PM
> Subject: Re: searching on dates?
> > Access to Archives (A2A) does indeed offer the functionality to search
> > dates.
> > However, this has been achieved (in the privacy of our online database)
> > exploiting the "eXtensibilty" of XML, ie. we were unable to achieve the
> > desired effect by actually conforming to the EAD DTD in this one regard,
> > had to bring in mercenary tags of our own...
> > The inability of EAD to encode a formal distinction between first and
> > dates (for date range searching) has always been a stumbling-block for
> > whilst trying to develop various EAD-based applications over the years.
> > there is the ability to encode a machine-readable, normalised version of
> > dates - but no actual *distinction* between first and last dates is
> > for.
> > So developers either have to get out their Regular Expressions and jump
> > through several hoops to tweeze out the two limits of the range from the
> > normal= attribute value, as in:
> > <unitdate normal="19010904-19670327">4 Sept. 1901 - 27 March
> > or come up with an 'innovative' use of EAD upfront, such as:
> > <unitdate label="first" normal="19010904">4 Sept. 1901 </unitdate>
> > <unitdate label="last" normal="19670327">- 27 March 1967</unitdate>
> > Personally, I would much rather see the ability to have something like:
> > <unitdate firstnormal="19010904" lastnormal="19670327">4 Sept. 1901 - 27
> > March 1967</unitdate>
> > or perhaps even something like:
> > <unitdate><firstdate normal="19010904">4 Sept. 1901</firstdate> -
> > <lastdate normal="19670327">27 March 1967</lastdate></unitdate>
> > I'm afraid I have to admit that for A2A, we ended up introducing the
> > tags <firstdate> and <lastdate> to achieve the desired search
> > And as a consequence from that point on, our data stopped being 'valid'
> > and became only 'well-formed' XML instead. Not to mention having to
> > these foreign tags out again when thinking about exchanging EAD data
> > other institutions...
> > Matt Hillyard
> > A2A Developer
> > The National Archives
> > London
> > -----Original Message-----
> > From: Ivo Zandhuis [mailto:[log in to unmask]]
> > Sent: 18 June 2003 09:28
> > To: [log in to unmask]
> > Subject: Re: searching on dates?
> > Access to Archives has the functionality to search on dates:
> > http://www.a2a.pro.gov.uk/search/index.asp
> > ------
> > Ivo Zandhuis
> > digital access to cultural information - research and consultancy
> > http://www.zandhuis.nl/index_en.html
> > ----- Original Message -----
> > From: "C. Perry Willett" <[log in to unmask]>
> > To: <[log in to unmask]>
> > Sent: Wednesday, June 18, 2003 12:30 AM
> > Subject: searching on dates?
> > > I'm implementing a system for search and display
> > > of EAD finding aids, and one feature that our
> > > archivists have requested is a search or limit by
> > > date. It's not easy, so I looked for examples of
> > > how other sites might do it. I have found only
> > > one site that has actually implemented a date search:
> > > Archival Resources (and it's a little misleading,
> > > since it seems to be only searching for dates that
> > > might explicitly appear in finding aids, and not
> > > for dates within ranges).
> > >
> > > I don't find any other site that uses dates at all,
> > > which raises a few questions for me. I had advised the
> > > archivists to encode dates and to use the "normal"
> > > attribute, and they're dutifully following directions.
> > > However, if we're not going to use them, why encode them?
> > > I realize that there might be a future payoff, but there
> > > are costs associated with encoding decisions today.
> > > Do people want to use dates in searching? If so, how?
> > > Why do no systems use them?
> > >
> > > Perry Willett
> > > Main Library
> > > Indiana University
> > > [log in to unmask]
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| Bill Landis
| Manuscripts Librarian, Special Collections and Archives
| The UCI Libraries, University of California
| P.O. Box 19557, Irvine, CA 92623-9557
| 949 824.3113 Voice | 949 824.2472 Fax
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