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2nd part of the west coast Open Annotation rollout: - Open Annotation Core Model http://www.slideshare.net/azaroth42/open-annotation-core-data-model-tutorial
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Cambridge Semantic Web MeetupMay 14th 2013 1Open Annotation Community Group
http://www.w3.org/community/openannotation/
Open Annotation Data Model:Specifiers and Specific Resources
Paolo Ciccarese [email protected] Harvard Medical School @paolociccarese
Robert Sanderson [email protected] Los Alamos National Laboratory @azaroth42
(Community Group Co-Chairs)
Massachusetts General Hospital
Cambridge Semantic Web MeetupMay 14th 2013 2Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers and Specific Resources
This module addresses several issues:
• Advanced Segmentation• Fragments are not expressive enough for use cases• Some media types do not have fragment definition at all
• Time and the Dynamic Web• Representations change and keep the same URI• Annotation may only apply to specific negotiated format
• Styling Annotation• Style is vehicle for human-only semantics (eg red strike-through)• Style may be referenced in comments (the green highlight)
• Scoping• Eg. the web page being viewed while an image was annotated
Cambridge Semantic Web MeetupMay 14th 2013 3Open Annotation Community Group
http://www.w3.org/community/openannotation/
Core Data Model
Annotation: The conceptual linkage between body and targetBody: The comment or resource which is “about” the TargetTarget: The resource which is being discussed
Cambridge Semantic Web MeetupMay 14th 2013 4Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specific Resources
Specific Resource: A resource that is somehow more specific or more precisely defined than the “source” resourceSource: The resource as identified by its URI
Cambridge Semantic Web MeetupMay 14th 2013 5Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specific Resources
Cambridge Semantic Web MeetupMay 14th 2013 6Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specific Resources also for the Body
Cambridge Semantic Web MeetupMay 14th 2013 7Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specific Resources also for the Body
Cambridge Semantic Web MeetupMay 14th 2013 8Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers
There are four types of Specifier that describe how the Specific Resource is different to the Source resource:
• Selector• Describes a segment of the resource
• State• Describes a state that the resource was in, via time or HTTP
• Style• Describes a Style (using CSS) for the Annotation
• Scope• References a resource which was being used for the Annotation
Cambridge Semantic Web MeetupMay 14th 2013 9Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Selectors
Selectors describe the segment of interest of a resource
Selectors are needed for several reasons:• Many media types do not have fragment specifications• Those that do often are not sufficiently precise in terms of description• Without knowing the media type, it is not possible to know how to
interpret a fragment• URIs are opaque strings, and systems normally do not try to look
within them for searching• Combinations of segment plus State, Style or Scope
The specification defines some general, cross-community selectorsCommunities may also define their own
Cambridge Semantic Web MeetupMay 14th 2013 10Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Selectors
Cambridge Semantic Web MeetupMay 14th 2013 11Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Selectors
Cambridge Semantic Web MeetupMay 14th 2013 12Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Selectors
Selectors defined:• Fragment Selector
• Range Selectors:• Text Position Selector• Text Quote Selector• Data Position Selector
• Area Selectors• SVG Selector
Cambridge Semantic Web MeetupMay 14th 2013 13Open Annotation Community Group
http://www.w3.org/community/openannotation/
Core Data Model: Fragment URIs
Cambridge Semantic Web MeetupMay 14th 2013 14Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Fragment Selector
Fragment Selector uses the fragment specifications to describe the segment:
• Useful in combination with other Specifiers• No need to reinvent the wheel!• Allows Specific Resource URI to be reused• Allows additional information to be attached, such as the specification
used to define the fragment
Current Fragment specifications include:• HTML, XML, RDF/XML• PDF • Plain Text• SVG • Media Fragments
Cambridge Semantic Web MeetupMay 14th 2013 15Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Fragment Selector
Cambridge Semantic Web MeetupMay 14th 2013 16Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Fragment Selector
Cambridge Semantic Web MeetupMay 14th 2013 17Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: SVG Selector
Media Fragments can only describe rectangles.SVG Selector allows arbitrary paths, circles, and so forth.
Cambridge Semantic Web MeetupMay 14th 2013 18Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: SVG Selector
Note that the client downloads the SVG resource in this case
Cambridge Semantic Web MeetupMay 14th 2013 19Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Text Selectors
Several intersecting issues require text based selectors:• HTML, PDF and Plain Text have fragment specifications, but only
Plain Text allows arbitrary spans of text• Other formats don’t have a specification at all• One text selector could be reused across formats of the same text• Quotations in Annotations allow otherwise protected texts to be
reproduced• Without the quotation and instead using character position,
changes to the text will invalidate the selector
We introduce two selectors:• Text Quote Selector• Text Position Selector
Cambridge Semantic Web MeetupMay 14th 2013 20Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Text Quote Selector
Cambridge Semantic Web MeetupMay 14th 2013 21Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Text Quote Selector
Cambridge Semantic Web MeetupMay 14th 2013 22Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Text Position Selector
Cambridge Semantic Web MeetupMay 14th 2013 23Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Text Position Selector
Cambridge Semantic Web MeetupMay 14th 2013 24Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: States
Selectors describe segments, but the URI of the Source identifies the generic web resource, not a particular representation.
The web is dynamic, representations change based on many factors; States allow us to record some of the factors to get back to the right representation.
We introduce two States:• TimeState:
• Time as a universal versioning mechanism, and pointing to archived copies of the resource
• HttpRequestState• Capture HTTP headers for content negotiation (etc)
Cambridge Semantic Web MeetupMay 14th 2013 25Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Time State
Cambridge Semantic Web MeetupMay 14th 2013 26Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Time State
Cambridge Semantic Web MeetupMay 14th 2013 27Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: HTTP Request State
Cambridge Semantic Web MeetupMay 14th 2013 28Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: HTTP Request State
Cambridge Semantic Web MeetupMay 14th 2013 29Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: CSS Style
Some Annotations should maintain the style choices of the creator, for example to not draw a black rectangle on an image of the night sky
Cambridge Semantic Web MeetupMay 14th 2013 30Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: CSS Style
Cambridge Semantic Web MeetupMay 14th 2013 31Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Scope
It is often useful to know in which context a resource was annotated.This is recorded as a Scope of the Specific Resource
Cambridge Semantic Web MeetupMay 14th 2013 32Open Annotation Community Group
http://www.w3.org/community/openannotation/
Specifiers: Scope