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RE: linearized tables

From: Charles McCathieNevile <charles@w3.org>
Date: Tue, 14 Mar 2000 22:29:52 -0500 (EST)
To: thatch@us.ibm.com
cc: gv@trace.wisc.edu, "'Greg Lowney'" <greglo@microsoft.com>, "'Wendy A Chisholm'" <wendy@w3.org>, w3c-wai-gl@w3.org, kasday@acm.org
Message-ID: <Pine.LNX.4.20.0003142227000.13739-100000@tux.w3.org>
When row-column position has meaning, until user agens are created that
actually let people deal with this (for example by navigating
tables) linearisation is not only very important but also fairly difficult.

The W3C tablin tool allows various linearisations, I believe including a
straight row/column reorientation, but also pulling out data cell by cell and
giving the assovciated headers, etc.

see http://www.w3.org/WAI/References/tablin or the WAI ER groups list of
tools - http://www.w3.org/WAI/ER/existingtools



On Tue, 14 Mar 2000 thatch@us.ibm.com wrote:

  How do you distinguish tables used for layout and those for tabular data? I
  think the distinction is when the row-column position has meaning.
  TV listings, for example, are "tabular data." The layout of tabular data
  lets the sighted user observe the row-column semantics. Layout and tabular
  data get kind of mashed together.  I think (hope) no one is arguing that
  tabular data needs to linearize well.  Instead, use appropriate table
  markup, TH elements and headers attributes, summary attribute and caption
  The example of a form whose input elements are placed in a table with
  labels in the cells above is tabular data because row-column position
  carries meaning. Clearly tabular data is not restricted to numbers. TV
  Listings have very few numbers. The Form example is no less a table than
  the TV listings. The Form example is properly marked up if appropriate
  table markup is used. Of course the form can also be marked up with the
  LABEL element.
  My bottom line is that when row-column position carries meaning, then
  linearization is not relevant.
  Jim Thatcher
  IBM Accessibility Center
  After 3/31/2000 jim@jimthatcher.com (512)306-0931
  "Gregg Vanderheiden" <gv@trace.wisc.edu> on 03/13/2000 08:46:25 PM
  Please respond to gv@trace.wisc.edu
  To:   "'Greg Lowney'" <greglo@microsoft.com>, "'Wendy A Chisholm'"
        <wendy@w3.org>, w3c-wai-gl@w3.org
  cc:   kasday@acm.org
  Subject:  RE: linearized tables
  Hi Greg,
  I think the problem is that most programs linearize by listing the items in
  the order they are appear in the HTML.  So labels above items would not
  linearize in any very usable fashion.
  This is not a problem with tables that present tabular information.  In
  case - the column headers across the top (If appropriately marked) would be
  the proper way to lay out a table.  (especially since there are usually
  labels down the side too.)  Not that the linearization rule does not apply
  to tables used for tabular information.
  It WOULD be a good idea for programs that linearize tables to give the user
  the option to flip it top-for-side to see if it were easier to understand
  use in that manner.  I don't know which ones do that though.   Anyone know
  of table linearizers with a flip layout function?
  -- ------------------------------
  Gregg C Vanderheiden Ph.D.
  Professor - Human Factors
  Dept of Ind. Engr. - U of Wis.
  Director - Trace R & D Center
  Gv@trace.wisc.edu, http://trace.wisc.edu/
  FAX 608/262-8848
  For a list of our listserves send "lists" to listproc@trace.wisc.edu
   -----Original Message-----
  From:     w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org]  On
  Behalf Of Greg Lowney
  Sent:     Monday, March 13, 2000 11:46 AM
  To:  Wendy A Chisholm; w3c-wai-gl@w3.org
  Cc:  kasday@acm.org
  Subject:  RE: linearized tables
  Hi Len, I don't necessarily disagree that it should be priority 1 to make
  tables understandable when linearized, but I don't like the example: "a
  laid out in a table with field labels on the top row and corresponding
  fields on the bottom row."
  I believe that complies with the guideline that requires the table to make
  sense when linearized. It is normal table behavior for the first row to
  label the entire columns, so from the standpoint of the guideline regarding
  linearization it should be OK to create a table whose first row contained
  labels for the form controls in lower rows. The responsibility then is on
  the agent doing the linearization to clearly express the labeling
  relationship between the column header and the cell contents. That's
  true whether the cell contains a control or any other content. Therefore I
  don't see the example as violating this guideline.
  However, the example would violate a second guideline, which is to ensure
  that implicitly-associated labels are properly positioned. That is Pri 2
  because it's assumed that the author will comply with the third guideline,
  that of providing explicitly-associated labels.
  -----Original Message-----
  From: Wendy A Chisholm [mailto:wendy@w3.org]
  Sent: Friday, March 10, 2000 12:08 PM
  To: w3c-wai-gl@w3.org
  Cc: kasday@acm.org
  Subject: Fwd: linearized tables
  >Resent-Date: Fri, 10 Mar 2000 11:39:32 -0500 (EST)
  >X-Sender: kasday@pop3.concentric.net
  >X-Mailer: QUALCOMM Windows Eudora Pro Version 4.2.2
  >Date: Fri, 10 Mar 2000 11:41:49 -0500
  >To: "wai-wcag-editor@w3.org" <wai-wcag-editor@w3.org>
  >From: "Leonard R. Kasday" <kasday@acm.org>
  >Cc: w3c-wai-er-ig@w3.org
  >Subject: linearized tables
  >Resent-From: w3c-wai-er-ig@w3.org
  >X-Mailing-List: <w3c-wai-er-ig@w3.org> archive/latest/1144
  >X-Loop: w3c-wai-er-ig@w3.org
  >Sender: w3c-wai-er-ig-request@w3.org
  >Resent-Sender: w3c-wai-er-ig-request@w3.org
  >WCAG says
  >5.3 Do not use tables for layout unless the table makes sense when
  >linearized. Otherwise, if the table does not make sense, provide an
  >alternative equivalent (which may be a linearized version). [Priority 2]
  >This means that someone could use tables for layout in way that the page
  >makes no sense and is not usable by any of todays user agents... but still
  >get an A conformance rating, because this is only priority 2.
  >For example, if there's a form laid out in a table with field labels on
  >the top row and corresponding fields on the bottom row.
  >I think the checkpoint needs to be Priority 1.
  >Leonard R. Kasday, Ph.D.
  >Institute on Disabilities/UAP, and
  >Department of Electrical Engineering
  >Temple University
  >423 Ritter Annex, Philadelphia, PA 19122
  >(215) 204-2247 (voice)
  >(800) 750-7428 (TTY)
  wendy a chisholm
  world wide web consortium
  web accessibility initiative
  madison, wi usa
  tel: +1 608 663 6346

Charles McCathieNevile    mailto:charles@w3.org    phone: +61 (0) 409 134 136
W3C Web Accessibility Initiative                      http://www.w3.org/WAI
Location: I-cubed, 110 Victoria Street, Carlton VIC 3053
Postal: GPO Box 2476V, Melbourne 3001,  Australia 
Received on Tuesday, 14 March 2000 22:29:56 UTC

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