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One of the goals of Access For All (AfA) metadata is to improve the findability of resources that meet individual user needs. This page describes a proposal for extending schema.org classes with AfA-compatible properties. schema.org is a collaboration between major search engines to develop and collect shared microdata formats to improve search results.

The Access For All metadata standard was designed to be used in conjunction with existing metadata standards and specification. The intention is that existing metadata can be supplemented with additional properties containing the AfA information. schema.org defines classes for common resource types and is already being used to describe those resources. One of the recommended approaches to extending the specification is to add properties to existing classes.

The general way that schema.org microdata works is as follows:

  • the itemscope attribute is added to the container of the thing being described. (In the case of HTML5 videos, this would be the <video> element. In the case of images, a container must be placed around the <img> tag.)
  • the itemprop attribute is added to information within the container. Typically, you might wrap the text of a name, for example, in a <span> with itemprop="name". The AfA information is not meant to be displayed. In this case, the <meta> element is used with the combination of itemprop and content attributes.

What would this look like in an Authoring Tool?

The primary resource types currently of concern within an OER authoring tool include images, videos and the document as a whole.

Notes on AfA metadata

  • a value of false for an is- or has- property implies that it is known definitively that the resource "does-not-" or "has-not-." If it cannot be known definitively one way or the other, the property should be omitted. In the comments below, I'm considering things we can infer automatically, not things an author can specify through direct knowledge.

Sample Image Markup

<div itemscope>
    <img src="http://foo.org/img.png" alt="alt text here"/>
    <meta itemprop="has-alt-text" content="true"/>
    <meta itemprop="has-long-description" content="false"/>
</div>

Sample Video Markup

<video itemscope src="http://foo.org/img.png">
    <meta itemprop="has-caption" content="true"/>
    <meta itemprop="has-transcript" content="true"/>
</video>

Sample Document Markup

<body itemscope>
    <meta itemprop="is-mouse-accessible" content="true"/>
    <meta itemprop="is-keyboard-accessible" content="true"/>
    <meta itemprop="is-display-transformable" content="font-size font-face foreground-colour background-colour"/>
    <meta itemprop="has-hazard" content="false"/>

    ...
</body>

Full Property List

Properties on CreativeWork (a parent class of articles, images, videos, etc)

Schemas use inheritance (multiple, in fact). Properties defined on CreativeWork will be inherited by ImageObject, VideoObject, etc.

Property

Expected Type

Description

Comments on application to OER Authoring Tools

is-mouse-accessible

boolean

The resource can be controlled using the mouse alone, if necessary

Assume always true for OER-as-a-whole

is-keyboard-accessible

boolean

The resource can be controlled using the keyboard alone, if necessary

At OER level: always true; At per-video level: true if our player, unknown if Flash. Summary should combine all.

is-display-transformable

Text

vocabulary: font-size, font-face, foreground-colour, background-colour

At OER level: all present; At per-video level: all present for our player, none present if Flash/youtube. Summary should combine all.

has-eBook

boolean

an eBook alternative is available

Known false at OER level.

uses-colour-coding

boolean

The resources uses colour to convey information.

Unknown at all levels.

has-hazard

Text

vocabulary: flashing, sound, olfactory, motion simulation

Known to have NO hazards at OER level and at image-level; unknown at video level. Summary should combine all.

has-text-representation*

boolean

a textual alternative is available

Normally, this is in reference to a specified original access mode. For OER authoring tools, we should use the refinements applicable to more specific media types, such as "captions"

has-audio-representation

boolean

an auditory alternative is available

False at OER level, unknown at image and video level.

has-tactile-representation

boolean

a tactile alternative is available

False at all levels

has-visual-representation

boolean

a visual alternative is available

 

has-audio-description

boolean

an audio description of the visual content is available

 

has-caption

boolean

a text caption of the auditory content is available

 

has-e-book

boolean

an e-book alternative is available

 

Properties on ImageObject

Property

Expected Type

Description

Comment on application to OER authoring tools

*has-alt-text

boolean

this resource has alt text available

 

*has-long-description

boolean

this resource has a long description available

I'm not sure if we can know this one.

Properties on VideoObject

Property

Expected Type

Description

Comment on application to OER authoring tools

*has-transcript

boolean

this resource has a transcript available

 

has-sign-language

boolean

a sign-language translation of the auditory content is available

We can't know this one definitively.

Where Properties Are Recorded In Web Content

Note: If something is "unknown," the metadata property should be absent (not false, not empty).

Note: Even if properties are always unknown, that fact will be summarized and so OER should be scanned for the property anyway.

* = scanned and summarized in "General" section of display
** = not sure how to summarize this one

On the OER describing the text, not including images or videos

Property

Assessment

*is-mouse-accessible

always true

*is-keyboard-accessible

always true

*is-display-transformable

always all values

*has-eBook

always false

*uses-colour-coding

always unknown

*has-hazard

always present but empty

On Images

Property

Assessment

*uses-colour-coding

always unknown

has-alt-text

true or false

has-audio-representation

always false (technically, it's unknown, but false for this iteration)

has-long-description

always false (technically, it's unknown, but false for this iteration)

On Audio Files

Property

Assessment

has-transcript

always false(technically, it's unknown, but false for this iteration)

has-visual-representation

always false (technically, it's unknown, but false for this iteration)

On Videos

Property

Assessment

*is-mouse-accessible

always true

*is-keyboard-accessible

true for our video player, unknown for youtube/Flash

*is-display-transformable

all values for our video player, present but empty for youtube/Flash

**has-caption

true or false depending on UniSub query;
note that caps in same language are "captions", those in different language are "subtitles" and count as "translations" in the summary

has-transcript

always false (technically, it's unknown, but false for this iteration)

*uses-colour-coding

always unknown

*has-hazard

always unknown

has-audio-description

always unknown

has-visual-representation

always unknown

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