My understanding is that if you include xlink:role, the value would have to be a URI, and you'd also have to choose between giving that element an xlink:type = simple | extended | locator | resource.
And I agree that this sounds exciting. One question, though: instead of defining all of this within the EAD, could you instead just give the <dao> an xml:id, like an ark (archival resource key)? Your external system would still contain the information about what "player" should be used, and that information could be passed on that way so that it could be embedded within other delivery systems.
Just a thought... obviously this would just ignore the issue, though (but, I also don't know of a single web browser that doesn't ignore most of the xlink specification anyway).
From: Encoded Archival Description List [mailto:[log in to unmask]] On Behalf Of Riley, Jenn
Sent: Thursday, July 29, 2010 2:22 PM
To: [log in to unmask]
Subject: xlink:role usage
Dear EAD folks,
I'm looking for some clearer guidance than what I've been able to find
online regarding the usage of xlink:role in EAD. In our finding aids, we use
<dao> to link to digitized versions of components in our collections. We're
now facing a situation where we can potentially be embedding players/viewers
inside our finding aid display instead of linking out to external systems,
which has got us pretty excited. But what this means for us is our <dao> now
needs to be able to indicate what "player" should be used for a given link.
Whether it's a paged digital object that needs a page turner to view, a
sound recording that needs an audio player, etc.
We're using the EAD2002 W3C XML Schema, and I'm thinking one of the xlink
attributes on <dao> would probably be best for encoding information about
what system should render a digitized archival object. Based on a review of
the brief information on linking elements in the EAD Tag Library, the old
Application Guidelines, and the W3C XLink specifications (which I'd never
really looked at before and was sorry after I tried to), I'm thinking
xlink:role is the most appropriate of the xlink attributes included in EAD.
Do other folks agree this is the right direction to go? Or should I be
looking at other options?
If xlink:role is the appropriate place, I'm still uncertain as to exactly
what the right usage should be. I see implementations and documentation that
treat xlink:role as requiring a QName (basically a string but can't start
with a number), in which case we could just use standardized terminology for
our different display options. But I also see implementations and
documentation which suggests these values should be full URIs. Is there a
clear best practice between these two options?
Would the semantics of xlink:role suggest the value be more appropriate as a
property of the object ('pageturned', 'audio', etc.) or more appropriate as
the name of the delivery system in which it should be rendered?
I'm not finding the W3C XLink documentation to be much help to me in
answering these questions. Does anyone know of other XLink resources that I
might find more useful as I learn about this?
Thanks for any thoughts you can provide,
Digital Library Program
Indiana University - Bloomington
Wells Library W501
Inquiring Librarian blog: www.inquiringlibrarian.blogspot.com