RE: alt tags for graphs

[Frank wrote] FYG about @longdesc:



I posted to the WCAG HTML Accessibility Taskforce list my thoughts on this
– I’ll briefly restate them here.



With the current proposal and previous requirements user agents were not
and still are not required to expose longdesc to users or required to make
it keyboard accessible.  It’s indicated that “user agents” should make them
keyboard accessible.  This perpetuates the idea that alternatives are only
needed for users who cannot see images or have images turned off.  This
denies people with low vision who are not using AT but like to see images
and people with cognitive disabilities access to the longer description.
This practice is one-size-fits one and isn’t universal design.  Users with
low vision may be able to see and decipher 8 out of 10 images but there may
be a few that they need the alternative text or longdesc to understand and
use.  The HTML specification in fact indicates that alt shall NOT be
display when images are displayed as it acts a replacement for images.  So
it’s not surprising the longdesc would follow down this same path as alt.



I have no problem with programmatically associating long description or
long description links with an image but it MUST be available to all user
groups without having to install special plug-ins or run assistive
technology  to access or make user agents display information that others
can access without such requirements.



Jonathan



*From:* Frank M. Palinkas [mailto:fmpalinkas@gmail.com]
*Sent:* Thursday, March 28, 2013 7:38 PM
*To:* David Woolley
*Cc:* Mattingly, F Darrell; WAI Interest Group; Guettler, Karen M
*Subject:* Re: alt tags for graphs



FYG about @longdesc:



////////////////////////////////////////////



*Shawn Henry* <shawn@w3.org>

Mar 12

**

**

to WAI, Steven, Charles, Janina, Paul, rubys, mjs, Judy, Michael, Philippe,
Michael(tm), www-archive, Robin

Dear WAI Interest Group Participants,

The W3C HTML Working Group today published the First Public Working Draft
of:
    HTML Image Description Extension
    http://www.w3.org/TR/html-longdesc

This specification ("HTML-longdesc") enables web authors to provide longer
text descriptions for complex images. It defines the "longdesc" attribute
to link descriptions with images in HTML5 content.

HTML-longdesc is an extension specification that is part of the HTML5
family of specifications [1], which enables it to evolve independently and
be finalized more rapidly. HTML-longdesc is part of W3C's work to ensure
that the Open Web Platform [2] is accessible to people with disabilities
[3].

Based on this publication, the following changes will be implemented in the
coming weeks:
* W3C validator [4] will validate longdesc as conforming HTML5.
* longdesc will be removed from the HTML obsolete features list.

Comments: Please send any comments on this Draft to the publicly archived
HTML Accessibility Task Force mailing list:
    public-html-a11y@w3.org
    by 10 April 2013

Working Groups: HTML-longdesc was developed by the HTML Accessibility Task
Force under the WAI Protocols and Formats Working Group (PFWG) and the HTML
Working Group (HTML WG). [5]

About the URI: The first URI above goes to the latest version of the
specification. The "dated" version of this Working Draft is: <
http://www.w3.org/TR/2013/WD-html-longdesc-20130312/> The difference
between these URIs are explained in Referencing and Linking to WAI
Guidelines and Technical Documents at: <http://www.w3.org/WAI/intro/linking>

Please let us know if you have any questions. Thank you in advance for your
comments.
Feel free to circulate this message to other lists; please avoid
cross-postings where possible.

Regards,
~Shawn Henry, WAI Outreach
HTML Accessibility Task Force Co-Facilitators: Steve Faulkner, Charles
McCathie-Neville, Janina Sajka
HTML WG Chairs: Paul Cotton, Sam Ruby, Maciej Stachowiak
PFWG Chair: Janina Sajka
W3C Staff: Judy Brewer, Michael Cooper, Philippe Le Hégaret, Michael Smith



////////////////////////////////////////



Kind regards,

Frank M. Palinkas
Senior Technical Writer

Quixey, Inc., Mountain View, California

Mobile: +1 650 248 5315

Web Accessibility and Standards tutorials:
http://dev.opera.com/author/947856



On Thu, Mar 28, 2013 at 4:00 PM, David Woolley <forums@david-woolley.me.uk>
wrote:

Mattingly, F Darrell wrote:


I’m working on a project to teach mathematical concepts.  What is the best
manner to describe graphs, such as the one below



Mathematics is about being precise.  There is no such thing as an alt tag
in HTML.  I think you mean an alt attribute.

I don't think it is possible to answer the question without knowing the
educational point that is being made in the particular case, however, I
suspect what you really needed was longdesc, except that it was never
usefully supported by mainstream browsers and may well have been removed.

Without longdesc, I think, as a minimum, you will need to include a link to
a textual description in the main text.

alt, in this case, can really only convey enough for someone already
familiar with the concepts to know what the intention of the diagram is.  I
don't think it can cover enough for someone who is expected to learn those
concepts.
-- 
David Woolley
Emails are not formal business letters, whatever businesses may want.
RFC1855 says there should be an address here, but, in a world of spam,
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