About Shared Canvas

Introduction
Shared canvas takes a step back from the current practice of representing repository data and images directly in HTML 4.01 Specification, instead requiring that this data be represented with RDF/XML Syntax Specification (Revised). Canonical XML Version 1.0 is a generalisation of HTML 4.01 Specification to permit encoding of arbitrary data, and RDF Primer is a means of modelling data as represented by a graph in which items are represented by nodes, and relationships between items by edges.

Documentation relating to shared canvas is available at the Shared Canvas site.

Documentating relating to the larger Open Annotation Collaboration initiative of which Shared Canvas is a contributing component is available at the Open Annotation Collbatoration site

Only a limited number of repositories manifest themselves through the shared canvas model. These include but are not necessarily limited to:

  • John Hopkins University
  • Margot (University of Waterloo)
  • Shared canvas demonstration site

XML/RDF
This interface merely returns the raw XML/RDF that the requested Shared Canvas is internally encoded as. This data would normally be accessed by Shared Canvas tools, such as our visualiser, hiding the low level XML constructs from the high level user. In raw mode the input is presented directly to the browser, which then presents in in whatever manner it chooses to present XML. When raw is not clicked, the input is instead embedded within a more standard imageMAT web page.

Visualisation
In order to use our visualiser tool which permits the graphic representation of an arbitrary shared canvas to be visualised and explored, you will need to enable Java within your browser. Otherwise the visualisation applet that we have developed will not run. The latest version of java can be obtained here, while manual download of a specific version of java for a specific machine can be achieved via here.

Once downloaded you will also have to enable the java plugin for your browser. To do this for Firefox, go to tools, select add ons, then plugins, and then ensure that the button associated with all java plugins says “disable”, implying that the plug in is currently enabled. If it says enable, enable by clicking on this button.

Our Document Management System (DMS) visualisation tool can also be used as an independent application.

Import
The import feature when presented with a Shared Canvas imports the images and annotations within this shared canvas into the named ImageMAT project folder located under the requesting users home directory. The user may then manipulate this information, directly within ImageMAT. Import essentially crawls the shared canvas documents, visiting each such document that is rooted under the shared canvas heirarchy, and extracting from all documents visited any images cited within that document. The ImageMAT heirarchy reflects the document heirarchy as so visited. Errors may be reported in the XML read, as they are detected. An informative table of links not navigated to, and images no imported is provided, whose purpose is to indentify weaknesses in the import (in missing material which should have been imported) or weaknesses in the shared canvas read (in erroneously naming elements etc). In verbose mode, every shared canvas document crawled is shown before being scanned. This is very useful in identifying the location of XML errors in the shared canvas.

Export
The export feature generates a shared canvas document describing the arbitrary project folder specified, and returns this shared canvas to the requester as an uploadable document.

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