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Re: Longdesc (was Re: BIG ISSUE -- re Delivery Units)

From: 'Jason White' <jasonw@ariel.its.unimelb.edu.au>
Date: Sat, 11 Feb 2006 11:06:02 +1100
To: w3c-wai-gl@w3.org
Message-ID: <20060211000602.GA5020@jdc>

On Fri, Feb 10, 2006 at 12:19:48AM -0600, Gregg Vanderheiden wrote:
> Ah
> 
> But the longdesc is not required to be IN the Web Unit. Just available from
> it.  so it doesn't matter if Longdesc is considered part of the Web Unit or
> not. 
> 
I'll try to clarify the issue. When I specify my conformance claim I give a
list of URI's or URI patterns. Each one refers to the primary resource of a
Web unit, using these terms according to the proposed definitions. The
conformance claim is that every Web unit so designated satisfies the
guidelines at one of the three levels.

If the long description is in a different Web unit from the HTML document
containing the LONGDESC attribute, and my list of URI's and URI patterns
doesn't include a reference to the long description, but only refers to the
document containing the LONGDESC attribute, then I think there's a problem. If
I'm being strict about evaluating the conformance claim, then when I come to
the document containing the LONGDESC attribute I say to myself: "there's a
LONGDESC attribute here that refers to something outside the scope of the
conformance claim". Now if 1.1.1 required only the presence of a LONGDESC
attribute, the HTML document would pass; but, in fact, 1.1.1 requires more
than that - it demands that the description convey the same information as the
image. To determine whether that is so, I have to read and evaluate the text
of the description, which is in the resource to which LONGDESC points, in a
different Web unit outside the scope of the conformance claim. Thus, the
HTML document containing the LONGDESC attribute doesn't conform to guideline
1.1 unless I take into account a Web unit that is beyond the scope of the
conformance claim. That's the anomaly: the conformance of a Web unit inside
scope of the claim depends on a Web unit that is out of scope, and I can't
think of anything in the guidelines that requires or allows an evaluator to
look outside the Web units about which the claim is made in assessing
conformance.

This also has interesting implications for metadata: could content be brought
into conformance by the existence of third-party metadata not covered by the
conformance claim?

> Yes?  
Received on Saturday, 11 February 2006 00:06:09 GMT

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