When you annotate a resource with a tag, you’d like to connect that tag to an external source, whether an authority file, a linked data node, or something else that represents unambiguously some data you want to associate with the annotated resource.
The IIIF Presentation 3.0 API does not itself discuss linking to external web resources in annotations, incorporating them from the W3C Web Annotation Data Model by reference. For a full description of this and other portions of the data model used in IIIF annotations, we recommend you read that document.
In order to make possible a link between the IIIF resource and an external web resource, the pertinent Annotation must have at least a
body that is a Specific Resource whose
source property contains the appropriate URI as its value. That
source value must resolve, that is, it must be a real URI at the time of the creation of the Annotation.
Finally, be sure you are writing valid value forms in your Annotation. In the Web Annotation data model, there are different patterns for the
value property, when used within an Annotation. The
value of a
TextualBody or a
FragmentSelector, for example, is a string rather than a JSON object. See also the Presentation API v3.0.
In this example, we continue our use of a photograph of a square in Göttingen, Germany, which includes a fountain topped by a sculpture of a girl and 2 accompanying geese. While the Annotation
body that points to the Wikidata entry for the fountain is valid all alone, we’ve added an additional
body to provide the viewer a natural language textual label to display to a person using that viewer.
body properties, as shown here, does not have any predictable consequences for a viewer’s handling of the data. With this in mind, each
body in this Manifest could stand alone.
No viewers currently implement this tagging approach.