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Re: crystal reports as html

From: Joe Clark <joeclark@joeclark.org>
Date: Fri, 24 Jan 2003 19:57:43 -0500 (EST)
To: WAI-IG <w3c-wai-ig@w3.org>
Message-ID: <Pine.BSO.4.40.0301240657070.5526-100000@ns1.seeto.com>

> If you have access to the original data used to generate the graph

Note: *Data*. Something difficult for humans to understand, which is
why we draw graphs.

> you
> should be able to generate a textual explanation of it as well

Here we go again. The WAI has a nasty habit of demanding that Web
authors create labour-intensive and indeed useless derivative works;
carries on as if such were even *possible* in the first place; and
avoids doing the same dirty work itself. WAI has a master-slave
relationship with authors: You struggle under the boulders so we can
enjoy the pyramids.

When it comes to long descriptions of charts and graphs, the
requirement
<http://www.w3.org/TR/WCAG10-HTML-TECHS/#long-descriptions> gives,
as its *full and complete* example, only the following:

<quoth>
   Example.
   <IMG src="97sales.gif" alt="Sales for 1997"
        longdesc="sales97.html">

   In sales97.html:

     A chart showing how sales in 1997 progressed. The chart
     is a bar-chart showing percentage increases in sales
     by month. Sales in January were up 10% from December 1996,
     sales in February dropped 3%, ..

   End example.
</quoth>

Note well the ellipsis. WAI cannot even be bothered to *write out a
genuine example* in *all* the detail they expect the rest of the
world to provide. In part this is because WCAG is so tremendously
poorly written.

It's a fatuous and irrelevant idea anyway. To quote myself (Chapter
6, page 85): "like packing, unpacking, and repacking a suitcase,
once some numbers are rendered graphically, it is not always easy or
straightforward to re-render that graphic in numbers (and words)."

I note that Charles rather revealingly uses the term "generate":
"you should be able to generate a textual explanation." Like it's
produced by a machine. Like it's even possible half the time. Also,
"a textual explanation" is a clumsy, euphemistic way to demand that
page authors *write coherent prose*, an ability WAI lacks. You know
you're in trouble if you're being told to mount an impossible
campaign, your leader shoulders none of the work, and your leader
can't even be bothered to tell it to you straight.

WAI members had at the time and possibly still have an incomplete,
casual, anecdotal knowledge of the true nature of charts and graphs.
(That's equally true for the true nature of *writing*, but we'll get
to that another day.)

If it were genuinely possible to transform many classes of *data*
into *coherent prose*, we wouldn't use graphs in those cases. Some
or even most of the time, it *is not possible* to transform data
into a graph into prose-- *if* you want to retain even significant
portions of the underlying meaning, let alone the myriad details
that become visible in graphing. (I would point to scatter charts,
error bars, outliers, and logarithmic scales as examples of
*information* that is not clear from the underlying data and resists
encapsulation in prose.)

I'm not a huge fan of Edward Tufte's books, but here's a challenge
for the WAI: Take ten examples from each of his volumes and
"generate a textual explanation" of them.
<http://www.edwardtufte.com/1176313877/tufte/books_vdqi>

-- 

  Joe Clark  |  joeclark@joeclark.org
  Author, _Building Accessible Websites_
  <http://joeclark.org/access/> | <http://joeclark.org/book/>
Received on Friday, 24 January 2003 19:57:46 GMT

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