Defined Types

Collection

An ordered list of Manifests, and/or further Collections. Collections allow Manifests and child Collections to be grouped in a hierarchical structure for presentation, which can be for generating navigation, showing dynamic results from a search, or providing fixed sets of related resources for any other purpose.

Manifest

A description of the structure and properties of the compound object. It carries information needed for the client to present the content to the user, such as a title and other descriptive information about the object or the intellectual work that it conveys. Each Manifest usually describes how to present a single compound object such as a book, a statue or a music album.

Canvas

A virtual container that represents a particular view of the object and has content resources associated with it or with parts of it. The Canvas provides a frame of reference for the layout of the content, both spatially and temporally. The concept of a Canvas is borrowed from standards like PDF and HTML, or applications like Photoshop and PowerPoint, where an initially blank display surface has images, video, text and other content “painted” on to it by Annotations, collected in Annotation Pages.

Range

An ordered list of Canvases, and/or further Ranges. Ranges allow Canvases, or parts thereof, to be grouped together in some way. This could be for content-based reasons, such as might be described in a table of contents or the set of scenes in a play. Equally, physical features might be important such as page gatherings in an early book, or when recorded music is split across different physical carriers such as two CDs.

Additional Types

This specification makes use of types defined in the [Web Annotation Data Model][org-w3c-webanno] specification, in particular the following:

Annotation Page

An ordered list of Annotations that is typically associated with a Canvas but may be referenced from other types of resource as well. Annotation Pages collect and order lists of Annotations, which in turn provide commentary about a resource or content that is part of a Canvas.

Annotation

Annotations associate content resources with Canvases. The same mechanism is used for the visible and/or audible resources as is used for transcriptions, commentary, tags and other content. This provides a single, unified method for aligning information, and provides a standards-based framework for distinguishing parts of resources and parts of Canvases. As Annotations can be added later, it promotes a distributed system in which publishers can align their content with the descriptions created by others. Annotation related functionality may also rely on further classes such as SpecificResource, Choice or Selectors.

Content

Web resources such as images, audio, video, or text which are associated with a Canvas via an Annotation, or provide a representation of any resource.

Annotation Collection

An ordered list of Annotation Pages. Annotation Collections allow higher level groupings of Annotations to be recorded. For example, all of the English translation Annotations of a medieval French document could be kept separate from the transcription or an edition in modern French, or the director’s commentary on a film can be separated from the script.

3. Resource Properties

Most of the properties defined by this specification may be associated with any of the resource types described above, and may have more than one value. Properties relate to the resource with which they are associated, so the label property on a Manifest is the human readable label of the Manifest, whereas the same label property on a Canvas is the human readable label for that particular view.

The requirements for which classes have which properties are summarized in [Appendix A][prezi30-appendixa].

Other properties are allowed, either via local extensions or those endorsed by the community. If a client discovers properties that it does not understand, then it MUST ignore them. See the [Linked Data Context and Extensions][prezi30-ldce] section for more information about extensions.

This section also defines processing requirements for clients for each of the combinations of class and property. These requirements are for general purpose client implementations that are intended to be used to render the entire resource to the user, and not necessarily for consuming applications with specialized use or individual component implementations that might be used to construct a client. The inclusion of these requirements gives publishers a baseline expectation for how they can expect implementations advertised as compliant with this specification to behave when processing their content.