Re: strawman with legend fix

Hey, folks–

I think I may have inadvertently caused some confusion; I didn't mean to 
imply that all the chart types should be drilled into that level of 
detail, that was just something to make sure we're thinking about the 
variety of chart types so we don't design a system that's too simplistic.

I do think the Chart Primitives section is pretty relevant. And I do 
think that different chart types may be best presented in different 
ways; for example, if you have 5-10 bars on a bar chart, stepping 
through them is pretty manageable, but if you have 50 points on a 
scatterplot, you have to have a different mode of interaction (like a 
trend line).

But in general, I agree with Amelia's user experience workflow, and it's 
fairly similar to what I hope to demo on Friday.

Regards-
-Doug

On 12/17/14 3:03 PM, Amelia Bellamy-Royds wrote:
> I just took a close look at Doug's Data Visualization Taxonomy, and I
> certainly would not want to see that level of complexity in an ARIA
> chart annotation system.
>
> It's still a very useful document, as a sampling of all the diverse
> types of charts that would need to be describable with the new
> annotation system.  However, I don't see a purpose in declaring separate
> role values for each chart type.  Not only is that an impossible task --
> there will always be charts that don't fit the taxonomy -- but it isn't
> terribly useful.  What are accessibility technologies supposed to do
> with that information?  Would they have separate rules for how to
> present each chart type?
>
> Instead, I think the focus should be on describing the /data/ -- the
> semantic meaning of a chart -- rather than describing its presentation.
> That allows data visualization designers to develop complex custom
> designs and still have a way of annotating them.
>
> For example, most data charts would contain
>
>   * A collection of datapoints each associated with certain categories
>     or certain values on a quantitative scale.
>
>   * Categorical scales or legends would contain the set of possible
>     values and an indication of whether they have a strict ordering.
>      From each category value, it would ideally be possible to access
>     the list of datapoints that are labelled by this category.
>
>   * Quantitative scales that would have
>       o max value, min value, units, and possibly step values;
>       o a description of the associated visual dimension
>         (horizontal/vertical position, element width/height/radius,
>         start angle, angle extent, color hue, color saturation,
>         brightness, etc.) to make it easier to understand prose
>         descriptions of the chart;
>       o the syntax could probably re-use some attribute names from the
>         ARIA range inputs.
>
> Ideally, an accessibility technology would be able to synthesize the
> information from the datapoints so that a user could start from
> information about a quantitative scale and then access information like
> max, min, median, etc. on that scale dimension, and jump to the
> associated data points in order, similar to using a sortable table column.
>
> I'm thinking a screen reader would say something like:
>
>   * "Scale 'Product Mass', displayed as vertical position, ranges from
>     min 0kg to max 30kg.  Associated with 33 data points, max value
>     27kg, min value 15kg.  Option: more statistics. Option: list
>     datapoints from max to min. Option: list datapoints from min to max..."
>
> Other charts would have contours instead of discrete datapoints (not
> sure how to describe those with words!).  And then of course there would
> be flow charts and graphs, where you have nodes and connectors, but both
> nodes and connectors might still be associated with categories or
> quantitative scales.
>
> Fred's taxonomy looks like a good starting point.  I have a couple
> quibbles -- e.g., I'm not sure why timelines need an "event" element
> separate from an "item", and I don't find "item" a particularly useful
> term -- but I expect to be on Friday's call so I look forward to a more
> detailed discussion.
>
> Best,
> Amelia Bellamy-Royds
>
> On 17 December 2014 at 09:12, Fred Esch <fesch@us.ibm.com
> <mailto:fesch@us.ibm.com>> wrote:
>
>     If you compare the taxonomy Doug and I did, you will see Doug dives
>     into specifics which is a nest of worms to work through.  I think we
>     should avoid diving down and rather spend our time identifying the
>     concepts of graphics which need to be relayed to a blind user.
>

Received on Thursday, 18 December 2014 08:09:46 UTC