Re: semantic level of SVG usage

Is the labeling of SVG supported by the primary screen readers at this time? Would your proposal mean that all screen readers would need to implement a second approach to providing information? 

Thanks,
Jonathan Cohn
AIR 
> On Aug 17, 2016, at 12:20 PM, Rich Morin <[email protected]> wrote:
> 
> Although I like the idea of adding ARIA metadata to SVG, I'm concerned
> that its effectiveness may be extremely limited by the semantic level
> of SVG tags and their typical usage.
> 
> # Motivation
> 
> Consider a data flow diagram, as produced by OmniGraffle. The building
> blocks of the diagram are geometric shapes and arrows, but this level
> of abstraction is largely absent from the SVG.  Instead, it uses either
> a filled `path` or a pair of `rect` elements.
> 
> And, although the semantic payload of the diagram is largely concerned
> with connectivity, the SVG contains no information on this.  The only
> way I can see to get connectivity information is to compare locations
> of line endpoints with the (fuzzy) boundaries of geometric shapes.
> 
> I have similar concerns about other kinds of plots and diagrams.  For
> example, the semantic payload of a pie chart or a histogram has to do
> with the numeric quantities being represented, not with the angles or
> heights used in the generated image.
> 
> The SVG images produced by D3.js are even more problematic, using tags
> which have only a distant relationship to the semantic payload:
> 
>  https://github.com/d3/d3/wiki/gallery
>  http://bl.ocks.org/mbostock
> 
> In summary, adding attributes to SVG tags may not be enough to make
> the resulting image particularly accessible.
> 
> # Proposal
> 
> By combining SVG attributes (e.g., object identity) with a separate
> section of the XML document, it would be possible to add arbitrary
> semantic information to the image.  For example, the added section
> could describe graph connectivity, encode raw data for plots, etc.
> 
> This could support a variety of post-processing needs, ranging from
> accessibility to machine learning.  And, because the added section
> wouldn't be part of the base SVG, programs could simply ignore it.
> 
> Comments and suggestions welcome.
> 
> -r
> 
> P.S.  Amanda Lacy, Johannes Rössel, and Gene Dronek contributed
>      valuable information and insights to this note, but they
>      are not responsible for my conclusions.
> 
> -- 
> http://www.cfcl.com/rdm           Rich Morin           [email protected]
> http://www.cfcl.com/rdm/resume    San Bruno, CA, USA   +1 650-873-7841
> 
> Software system design, development, and documentation
> 
> 
> 
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