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Re: ACTION-325 - 3.3.2 Location in Hierarchy

From: Greg Lowney <gcl-0039@access-research.org>
Date: Wed, 31 Mar 2010 22:47:07 -0700
Message-ID: <4BB4335B.4030904@access-research.org>
To: simon.harper@manchester.ac.uk
CC: UAWG list <w3c-wai-ua@w3.org>
Simon, thanks for trying to flesh this out; it's a tough one. A few thoughts:

1. The current wording is not limited to displaying the path from the root to some particular node (e.g. the currently selected node in the presentation); it says "leading from" but should probably add something equivalent to a "to" clause.

2. I believe I understand what you're trying to say with the two categories, but I could be wrong, and in either case I don't think the distinction would be clear to someone who hadn't been in on our discussion. Are you saying that the user agent should expose hierarchies that are conveyed by the normal visual or audio presentation, but it is not required to expose hierarchies that may be present in the markup if they're invisible to the typical user? If that's right, can the group provide some examples of both categories? Or are you saying the HTML structure not be something the UA would represent for the SC, because it's "an explicitly logical structure with defined semantics"?

3. In the example, might list a tree along with breadcrumbs as typical ways of satisfying this criterion.

4. The Intent section talks about efficient keyboard navigation, but the success criterion doesn't address or require this. As written, it would be enough to (for example) provide a command to display a separate window with static text describing the hierarchy; that certainly would not help with navigation. If we want to make sure this provides navigation, then we could make the explicit, but isn't that overlapping section 4.7 (Provide structured navigation)?

5. In fact, should perhaps 3.3.2 (Location in Hierarchy) be entirely subsumed into 4.7 (Provide structured navigation) to the extent it's not already covered there? If not, can we make clearer the distinction between them?


-------- Original Message  --------
Subject: ACTION-325 - 3.3.2 Location in Hierarchy
From: Simon Harper <simon.harper@manchester.ac.uk>
To: UAWG list <w3c-wai-ua@w3.org>
Date: 3/8/2010 4:07 AM

Hi there,

Here's my text for ACTION-325 to be added to this weeks survey.

3.3.2 Location in Hierarchy: The user can view the path of nodes leading
from the root of any content hierarchy in which the structure and
semantics are implied by presentation, as opposed to an explicit logical
structure with defined semantics (Level AA).

* Intent of Success Criterion 3.3.2:
Knowing where you are in a hierarchy (e.g., tree node, nested frame)
makes it easier to understand and navigate information. Users who are
perceiving the data linearly (such as audio speech synthesis) do not
receive visual cues of the hierarchical information. Within constructs
that have explicit logical structure such as a Java Tree node,
navigation is tied to a users understanding of what that construct
actually represents. With a tree node made of individual HTML and script
layered with styling, the user has no idea what the combined individual
components mean, and therefore does not know how to navigate the
hierarchy or what to expect once interaction is underway. Efficient
navigation of hierarchical information reduces keystrokes for people for
whom keypress is time-consuming, tiring, or painful. For people with
some cognitive disabilities, providing the clear hierarchy reduces
cognitive effort and provides organisation.
* Examples of Success Criterion 3.3.2:
o A media player provides a hierarchical display of playlists, albums,
artists and songs, etc. When the user selects an individual item, a
breadcrumb of the categories is displayed, can be navigated and is
available programatically.
* Related Resources for Success Criterion 3.3.2:
o To be written



Simon Harper
University of Manchester (UK)

Human Centred Web Lab: http://hcw.cs.manchester.ac.uk

My Site: http://hcw.cs.manchester.ac.uk/people/harper/

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Received on Thursday, 1 April 2010 05:47:34 UTC

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