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The A11yMetadata Project seeks to extend schema.org by including new properties to address the accessibility and discoverability of resources on the Web.

A majority of properties and terms in this proposal are a subset derived from the IMS Global Learning Consortium's Access For All specification. Included with permission from the IMS Global Learning Consortium for use by schema.org


(Definitions for most of the expected values can be found in the IMS Global Access for All (AfA) Information Model Data Element Specification.)

Property Expected Type Expected Values Description
accessMode Text
  • auditory
  • colorDependent
  • tactile
  • textOnImage
  • textual
  • visual
An access mode through which the intellectual content of a described resource or adaptation is communicated; if adaptations for the resource are known, the access modes of those adaptations are not included.
mediaFeature Text
  • alternativeText
  • audioDescription
  • braille
  • captions
  • ChemML
  • describedMath
  • haptic
  • highContrast
  • largePrint
  • latex
  • longDescription
  • MathML
  • nemethBraille
  • signLanguage
  • structuralNavigation
  • tactileGraphics
  • transcript
Accessible content features included with the resource.
hasAdaptation URL Identifier of a resource that is an adaptation for this resource.
isAdaptationOf URL Identifier of a resource for which this is an adaptation.
accessAPI Text
  • AndroidAccessibility
  • ARIA
  • ATK
  • AT-SPI
  • BlackberryAccessibility
  • iAccessible2
  • iOSAccessibility
  • JavaAccessibility
  • MacOSXAccessibility
  • MSAA
  • UIAutomation
Indicates that the resource is compatible with the referenced accessibility API.
ATCompatible Boolean The resource is compatible with assistive technologies. For example, that the resource complies to WCAG 2.0 checkpoints: 1.1.1, 1.3.1, 1.3.2, 2.4.4, 3.1.1, 3.1.2, 3.3.2, 4.1.1, 4.1.2.
displayTransformability Text
  • css
Identifies modifiable display characteristics of the described resource.
controlFlexibility Text
  • fullKeyboardControl
  • fullMouseControl
Identifies a single input method that is sufficient to control the described resource.
accessHazard Text
  • flashing
  • motionSimulation
  • sound
A characteristic of the described resource that is physiologically dangerous to some users.

Extensions fo bookFormatType

This proposal also requests the expansion of the bookFormatType enumeration to include the following formats:

  • DAISY202
  • DAISY3
  • EPUB2
  • EPUB3

Example Markup

Example 1

The following example shows how the accessibility metadata will be used to enhance Bookshare records:

  1. <div itemscope="" itemtype="http://schema.org/Book">
  2.    <link rel="bookFormat" href="http://schema.org/EBook"/>
  3.    <meta itemprop="accessMode" content="textual"/>
  4.    <meta itemprop="accessMode" content="visual"/>
  5.    <meta itemprop="isAdaptationOf" content="urn:isbn:9780030426599"/>
  6.    <meta itemprop="ATCompatible" content="true">
  7.    <meta itemprop="controlFlexibility" content="fullKeyboardControl">
  8.    <meta itemprop="controlFlexibility" content="fullMouseControl">
  9.    <meta itemprop="displayTransformability" content="css">
  10.    <meta itemprop="mediaFeature" content="longDescription">
  11.    <meta itemprop="mediaFeature" content="alternativeText">
  13.    <dl>
  14.       <dt>Brief Synopsis:</dt>
  15.       <dd itemprop="description">NIMAC-sourced textbook</dd>
  16.       <dt>Long Synopsis:</dt>
  17.       <dd>N/A</dd>
  18.       <dt>Book Quality:</dt>
  19.       <dd>Publisher Quality</dd>
  20.       <dt>Book Size:</dt>
  21.       <dd itemprop="numberOfPages">598 Pages</dd>
  22.       <dt>ISBN-13:</dt>
  23.       <dd itemprop="isbn">9780030426599</dd>
  24.       <dt>Publisher:</dt>
  25.       <dd itemprop="publisher" itemtype="http://schema.org/Organization" itemscope="">Holt, Rinehart and Winston</dd>
  26.       <dt>Date of Addition:</dt>
  27.       <dd>06/08/10</dd>
  28.       <dt>Copyright Date:</dt>
  29.       <dd itemprop="copyrightYear">2007</dd>
  30.       <dt>Copyrighted By:</dt>
  31.       <dd itemprop="copyrightHolder" itemtype="http://schema.org/Organization" itemscope="">Holt, Rinehart and Winston</dd>
  32.       <dt>Adult content:</dt>
  33.       <dd><meta itemprop="isFamilyFriendly" content="true"/>No</dd>
  34.       <dt>Language:</dt>
  35.       <dd><meta itemprop="inLanguage" content="en-US"/>English US</dd>
  36.       <dt>Essential Images:</dt>
  37.       <dd>861</dd>
  38.       <dt>Described Images:</dt>
  39.       <dd>910</dd>
  40.       <dt>Categories:</dt>
  41.       <dd><span itemprop="genre">Educational Materials</span></dd>
  42.       <dt>Grade Levels:</dt>
  43.       <dd>Sixth grade, Seventh grade, Eighth grade</dd>
  44.       <dt>Submitted By:</dt>
  45.       <dd>Bookshare Staff</dd>
  46.       <dt>NIMAC:</dt>
  47.       <dd>This book is currently only available to public K-12 schools and organizations in the United States for use with students with an IEP, because it was created from files supplied by the NIMAC under these restrictions. Learn more in the NIMAC Support Center.</dd>
  48.    </dl>
  50.    <div class="bookReviews" itemprop="aggregateRating" itemscope itemtype="http://schema.org/AggregateRating">
  51.       <h2>Reviews of Holt Physical Science (<span itemprop="reviewCount">0</span> reviews)</h2>
  53.       <div class="bookReviewScore">
  54.          <span><span itemprop="ratingValue>0</span> - No Rating Yet</span>
  55.       </div>
  56.    </div>
  57. </div>

(The source record can be found at https://www.bookshare.org/browse/book/190639.)

Example 2

This example shows how the accessibility metadata can be used to augment a record for a video:

  1. <dl itemtype="http://schema.org/VideoObject" itemscope="">
  2.   <dt>Title:</dt>
  3.   <dd itemprop="name">Arctic Climate Perspectives</dd>
  4.   <dt>Description:</dt>
  5.   <dd itemprop="description">This video, adapted from material provided by the ECHO partners,
  6.     describes how global climate change is affecting Barrow, Alaska.</dd>
  7.   <dt>Adaptation Type:</dt>
  8.   <dd><span itemprop="mediaFeature">captions</span></dd>
  9.   <dt>Access Mode:</dt>
  10.   <dd><span itemprop="accessMode">auditory</span>, <span itemprop="accessMode">visual</span></dd>
  11.   <dt>URL:</dt>
  12.   <dd><a itemprop="url" href="http://www.teachersdomain.org/asset/echo07_vid_climate">http://www.teachersdomain.org/asset/echo07_vid_climate</a>/</dd>
  13.   <dt>Has Adaptation:</dt>
  14.   <dd><a itemprop="hasAdaptation" href="http://www.teachersdomain.org/asset/echo07_vid_climate_dvs/">http://www.teachersdomain.org/asset/echo07_vid_climate_dvs/</a></dd>
  15.   <dt>Subjects:</dt>
  16.   <dd><span itemprop="about">National K-12 Subject::Science::Earth and Space Science::Water Cycle, Weather,
  17.     and Climate::Structure and Composition of the Atmosphere, National K-12 Subject::Science::Earth and
  18.     Space Science::Water Cycle, Weather, and Climate::Climate</span></dd>
  19.   <dt>Education Level:</dt>
  20.   <dd>Grade 6, Grade 7, Grade 8, Grade 9</dd>
  21.   <dt>Audience:</dt>
  22.   <dd><span itemprop="intendedEndUserRole">Learner</span></dd>
  23.   <dt>Resource Type:</dt>
  24.   <dd><span itemprop="genre">Audio/Visual</span>, <span itemprop="genre">Movie/Animation</span></dd>
  25.   <dt>Language:</dt>
  26.   <dd><span itemprop="inLanguage">en-US</span></dd>
  27.   <dt>Publication Date:</dt>
  28.   <dd itemprop="datePublished">2007-02-12</dd>
  29.   <dt>Rights:</dt>
  30.   <dd>Download and Share, <a itemprop="useRightsUrl" href="http://www.teachersdomain.org/oerlicense/2/">http://www.teachersdomain.org/oerlicense/2/</a></dd>
  31. </dl>

Discussion and Related Work