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More ISSUE 30 @longdesc use cases

From: Laura Carlson <laura.lee.carlson@gmail.com>
Date: Tue, 24 Aug 2010 11:14:11 -0500
Message-ID: <AANLkTi=tHGtfwXLXRDZwT-1FDWP2cB67MMTVHPyv=rCg@mail.gmail.com>
To: Joshue O Connor <joshue.oconnor@cfit.ie>
Cc: HTML Accessibility Task Force <public-html-a11y@w3.org>, HTML WG <public-html@w3.org>, W3C WAI-XTECH <wai-xtech@w3.org>, Barry McMullin <barry.mcmullin@dcu.ie>
Hi Josh,

Here are a few more longdesc use cases in the wild:

Federal Deposit Insurance Corporation

Hawaii's Public Schools: Seizures Flow Chart

Interagency Committee on Disability Research (ICDR)

Health and Safety Executive

Commuter Choice Primer
Research and Innovative Technology Administration (RITA)  Department
of Transportation

Best Regards,

On 8/23/10, Joshue O Connor <joshue.oconnor@cfit.ie> wrote:
> Hi,
> I have come across a couple of interesting @longdesc use cases. The
> first is by Laura Carslon which used "A11y Resolved Bug Comparisons"
> graphs and pie charts. Describing a pie chart and graph like the
> examples Laura provide would be extremely difficult without an attribute
> like @longdesc, if you don't want the descriptions to appear inline. [1]
> To expand on this problem, the need for an off page long descriptor is
> made even clearer in the following example from 2006 (courtesy of Prof.
> Barry McMullin of DCU) which he describes as a "Double-negative use
> case". [2]
> To explain - I will quote Barry directly from the CFIT website.
> "Double-negative" because longdesc is not being used here — but I would
> have liked to use it, and its use would have been absolutely
> appropriate! It's just that weak user-agent support meant that using it
> would potentially have left the long description actually unavailable to
> people who might benefit from it. So instead, I decided to compromise
> (somewhat) the experience of people who already could perceive the
> graphical image perfectly well, and exposed the long description for all
> users (even though it is redundant for the majority). This decision
> then, logically, had the further effect of requiring an explanation —
> for those majority users — of what a long description is and why — which
> explanation, in turn, is redundant for those users who would normally
> actually benefit from a long description!
> I humbly suggest that such a convoluted (nay, "traumatic"!) design
> decision — genuinely existing "in the wild" — should count as legitimate
> evidence of the use-case-need for longdesc!?" [3]
> To me the above example, compounds the first and illustrates that an off
> page long descriptor is very much needed but due to the authors concerns
> about UA support etc he decided /not/ to use it. This implies that:
> 1) A long descriptor, that can potentially reference a URI and can be
> recognised and handled in a way that is conducive to a positive user
> experience for an AT user is actually needed.
> 1) The consequences of having to include a very verbose description
> inline can be problematic in terms of page bloat, potential perceived
> complexity for users with cognitive disabilities and possibly other
> usability issues, such as general confusion as to the descriptions
> purpose for non-users of AT.
> Josh
> [1] http://www.d.umn.edu/~lcarlson/html5bugchart/20100821/
> [2] http://www.aishe.org/readings/2007-1/No-14.html#x20-19300014.6
> [3] http://www.cfit.ie/news-and-commentary-archive/525-longdesc-rip

Laura L. Carlson
Received on Tuesday, 24 August 2010 16:14:45 UTC

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