A few thoughts on the relationship between the REACH Element Set and the
Dublin Core....
The scope of the Dublin Core has changed over the course of its
development, and consequently there are some differences of interpretion
as to its role in life; I haven't seen any responses from DC people on
this list yet, so I hope the interpretation I give here isn't too
inaccurate. I'm cross-posting it to the meta2 list, so hopefully I'll be
notified if I get any of this wrong!
DC (or the Dublin Core Metadata Element Set) was originally intended as
a means by which 'document-like objects' on the Internet could be simply
and easily described as an aid for resource discovery; however, DLO's
were only ever defined by example. Although from the outset it was
envisaged that web pages would be the most significant area for
deployment of DC, it has never been limited solely to this application.
Subsequent workshops have gradually extended the scope of DC; The 2nd
workshop resulted in the Warwick Framework, a conceptual container
architecture for diverse metadata 'packets' of varying flavours. The 3rd
workshop focussed on the use of DC to describe images, and consensus was
reached that, with a bit of shuffling of the element names and
definitions (e.g. AUTHOR --> CREATOR), DC could realistically be used
for images. This led to the extension of the 'Document Like Object'
concept to include almost any static information object that appeared
identically to all viewers, i.e. things that don't change according to
any input parameters or point of view. The 4th workshop, earlier this
year in Canberra, introduced the notion of optional qualifiers (TYPE,
SCHEME & LANG), which can be used to refine (but not extend) the scope
of individual elements, link them to formal schemes and indicate the
language in which the metadata (as distinct from the data, which has
it's very own element) is encoded.
What hasn't changed is the role of DC -- it is a tool for encoding
metadata for resource discovery, and should always be used to describe
networked digital resources. The REACH Element Set, however, is a common
set of elements for describing the properties of museum object records.
However, there is a lot of tension here, as Murtha rightly points out;
if a digital resource contains information about an object, or even a
surrogate of an object, then much of the metadata needed for effective
retrieval of the digital resource needs to be 'inherited' from objects
&/or their surrogates along the way (don't worry, I'm not going to start
waffling about object-oriented techniques etc. ;-). This is where the
apples and oranges start to get mixed up.
This is not so much of a problem for bibliographic information, where
information about the 'work' is usually far more significant for
retrieval purposes than information about it's physical manifestation.
We also ran into this difficulty recently at the Visual Arts, Museums &
Cultural Heritage Metadata Workshop, and have produced a draft set of
optional DC qualifiers that are intended to address the problem of
distinguising between original objects, surrogate objects and network
resource objects, and also between digital and analogue objects. These
recommendations for visual-arts-&-museum-specific DC qualifiers are
still being reviewed by an Editorial Board, but have been mapped to the
draft REACH Element Set and will be available on the web from 9 June at
http://vads.ahds.ac.uk/Metadata4.html. The rest of the report is already
available, at http://vads.ahds.ac.uk/Metadata1.html. There is also a
review of pertinent standards at http://vads.ahds.ac.uk/standards.html.
Clearly, although the values stored in the REACH and Dublin Core sets
may be closely related in the case of networked museum information, the
two have a fundamentally different role; REACH will be used for storing
data about museum objects, DC is used for metadata about networked
resources. Compatibility between the two is still very important though,
because Dublin Core metadata can then be more effectively used to
describe REACH data records for networked retrieval.
Murtha Baca wrote:
> [Dublin Core] is intended as an access tool for web pages (at least that's
> how I understand it as well), but in my humble opinion it also mixes
> apples and oranges -- the "object," whatever it might be, and the
> "surrogate," be it digital image, text document, etc.
> Maybe if we all keep thinking about this, it will all become clear in the
> end...
I hope so!
cheers,
T.
-- Tony Gill ---------------------- Programme Leader: ADAM & VADS --
Surrey Institute of Art & Design * Farnham * Surrey * GU9 7DS * UK
Tel: +44 (0)1252 722441 x2427 * Fax: +44 (0)1252 712925
-- [log in to unmask] -- http://adam.ac.uk -- http://vads.ahds.ac.uk/ --
