On Thu, 10 Feb 2005, Pete Johnston wrote:
> What are we really achieving by doing this?
> In the absence of a MODS RDF binding, what is anyone gaining by asking LoC to
> define two or three RDF properties called
> (and the other two or three things needed for the DC Lib AP - I've just guessed
> the URIrefs) picked pretty much from random parts of the MODS data structure.
> It provides _no_ interoperability whatsoever between DC and MODS XML because
> we've just picked out some tiny part of the MODS data structure.
> Why are we _insisting_ on "reuse" in this rather odd piecemeal sort of way,
> instead of simply declaring the properties required within DCMI vocabularies?
...and then later...
> So given that no RDF binding for MODS exists, (IMHO) the only reason for
> choosing to create a new property called
> rather than choosing to create a new property called
> is that presumably it would be "owned"/managed by LoC rather than by
> DCMI - and I have to admit it seems slightly odd (to me!) that we are
> considering asking LoC to do this - to coin a handful of properties,
> representing only two or three (fairly arbitrary) facets of the MODS
> information model.
At a technical level, I agree with you - it doesn't really matter whether
a new term is assigned a DC URI or a MODS/LoC URI. And there are
certainly some advantages (simplicity being the prime one) in favour of
taking the terms we are interested in and plonking them into a DC
namespace (i.e. assigning them a DC URI).
But, IMHO, the reasons for promoting the use of LoC, LOM and other URIs
for existing terms has to do with the fuzzier social and political
benefits this brings in terms of ownership, buy-in by the community and so
on. I don't think we'll get buy-in to the DCMI approach by effectively
saying to those communities, "We liked your XML element so much, we've
taken a copy of it and added it to a DCMI namespace"!?
Instead, we need to find ways of explaining to them the benefits of the
semantic Web approach. We've got to explain why we need an agreed
underlying model (such as that provided by RDF) before we can mix and
match metadata terms in the way we want. We've got to explain why an
approach based on simply merging together lots of XML fragments doesn't
scale beyond very limited cases where you've got explicit agreement of all
the parties. We need to convince these other communities that it is worth
their while re-casting the semantics of their metadata terms in an RDF
My guess is that other communities will want to feel ownership of the
metadata terms that they create (just as we feel most comfortable with
dc:title being dc:title and not being redeclared as somethingelse:title).
And they'll only feel comfortable with DCMI if they think we are giving
more than we are taking. In any case, I don't see that DCMI particularly
wants to lumber itself with maintaining a whole set of metadata terms that
are already defined and used by other communities.
All in all, I think we (primarily the Architecture WG and the Usage Board)
need to explain not only the 'Whys' above, but also the 'Hows'. How do I
declare my XML element as a property in RDF? How do I assign a URI to my
term? How do I declare my controlled vocabulary as a DCMI encoding
scheme? Etc, etc. I know that Pete is already working on some of the
documentation that will help to do this.
None of which is easy on a shoestring! :-(
However, I do agree with you that the metadata 'application profile'
notion of mixing and matching has tended to be interpretted much too
simplisticly - and outside of its original context of the semantic Web -
to mean "as long as it's in XML it must be OK" pretty much! But next time
someone says to me that they've got an XML element that they're going to
use as a DCMI property, rather than saying "you can't do that" (which is
probably what it sounded like I said this time!) I'm going to try saying,
"OK, but in order to do that, you need to do the following...".
Well, maybe... :-)
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