Re: SVG accessibility - title, description and what to do with it

My first approach:

I would not describe everything in the top level. I would include the
information about individual bars at the level of individual bars. As an
example, I would write something like the following structure (I leave the
encoding of the graphics bits to a tool, but the structure is the key...)

<svg ...>
  <title>population of countries</title>
  <desc>(One might put a general summary here, but there isn't a sensible one
  I can think of for this example - it doesn't convey any further
  message...)</desc>

  <g id="axes">
  <title>country name versus population</title>
  </g>

  <g id="australia">
  <title id="au">Australia</title>
  <desc>three blokes and a dog</desc>
  <text><tref xlink:href="oz"/></text>
  </g>

  <g id="newZealand">
  <title id="nz">New Zealand</title>
  <desc>Some people with a lot of possums and sheep</desc>
  <text><tref xlink:href="nz"/></text>
  </g>

etc...
</svg>

This is a fairly flat structure, but thenn a simple bar graph is. I would
expect that a useful presentation allows someone to just get the title for
the whole thing (and possibly the desc), or to actually go through the
details. Whether the mechanism is that they change what is rendered, or their
browser lets them skip through based on structure, is a detail of how they
use their software. I would expect serious browsers to provide both
options, although many simpler ones are likely to choose one or the other.

Part of my concern (and I hope and suspect this is also something Adobe are
thinking about...) is that this should enable good support for authors from
their tools. It should be fairly trivial to take the information above from a
spreadsheet or other tabular representation of the data and automatically
turn it into a graphic representation.

Charles McCN

On Fri, 7 Sep 2001, Loretta Guarino Reid wrote:

  Let me present a hypothetical example, to see if that makes my question
  clearer.

  Suppose I use SVG for a bar chart. The bar chart will contain some text
  labeling values on the axes, at least. But the text alone will by no means
  communicate the information in the bar chart.

  Would I attach a description to the entire bar chart? to the individual bars
  in the chart? if I describe the bars in the chart, should the top-level
  description duplicate the information about the values of the individual bars?
  or just indicate that this is a bar chart plotting X against Y?

  It seems that I need to know something about the way this information will be
  presented to know how to author it properly.

  	Loretta



-- 
Charles McCathieNevile    http://www.w3.org/People/Charles  phone: +61 409 134 136
W3C Web Accessibility Initiative     http://www.w3.org/WAI    fax: +1 617 258 5999
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Received on Saturday, 8 September 2001 16:41:55 UTC