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Re: Tables and the meaning of "equivalent", an overdue reply

From: Jason White <jasonw@ariel.ucs.unimelb.edu.au>
Date: Wed, 1 Dec 1999 15:11:30 +1100 (EST)
To: WAI Interest Group <w3c-wai-ig@w3.org>
Message-ID: <Pine.SOL.4.10.9912011459280.17994-100000@ariel.ucs.unimelb.edu.au>
My personal experience has been that in the case of genuine data tables,
linearisation is often not the best strategy, since one needs to be
continually aware of which headers apply to the current data cell, and
this is best captured by a spatial metaphor, where practicable. Thus,
although it frequently proves necessary to linearise tables in the
production of braille documents, the columnar format is preferred whenever
it is not precluded in principle by considerations of space (the limited
length of the braille line vs. the number of characters in each data
cell). Likewise in audio, one can retain the spatial orientation by
projecting the spoken rendering of the table stereophonically and
adjusting the relative volume of each speaker to convey the column
position of each cell, so that the sound shifts from left to right, for
example, as a row of the table is read. This is essentially what T. V.
Raman's AsteR software does when used with appropriate hardware.

When linearisation of data tables is needed, one can use appropriate
techniques to represent the header and data cell relationships. I
understand that there is software under development whih does this,
relying where necessary on HEADER, SCOPE and AXIS attributes of HTML 4.0.

With regard to tables which are used for layout, I do not personally find
that significantly informative content is lost when these are simply
linearised (for instance as in the Lynx browser), though others may

Finally, it should be added that Emacspeak offers reliable table
navigation facilities when used with the Emacs/W3 web browser. I am sure
that other speaking browsers offer functionality in this area as well.
Received on Tuesday, 30 November 1999 23:14:09 UTC

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