Linking to Structured Metadata

Use Case

You have a IIIF manifest resource along with additional machine-readable metadata usable by aggregators and others that can process or index it via the seeAlso property. You know from previous experience that aggregators crawling your collection harvest best when handed structured metadata and are also then able to offer their readers faceting capabilities, making your resources amenable to focused discovery. Through use of the seeAlso property, you are able to alert an aggregator to the presence of a dataset so the aggregator can provide appropriate and sophisticated information about your resource to the aggregator’s users.

Implementation Notes

This property is used for pointing a viewer to the URI of a non-IIIF resource with information about the IIIF resource to which it is attached. Most frequently, the non-IIIF resource will be structured metadata, and to be most effective, the target resource should be a machine-readable format such as XML, JSON, or RDF. The type value for seeAlso is usually dataset.

Three other properties may seem similar, so it’s worth highlighting the differences.

  • homepage (IIIF Presentation API reference)
    Where rendering presents an additional representation of the same resource, homepage points to a webpage about the object represented by the resource.

  • accompanyingCanvas (IIIF Presentation API reference)
    An accompanyingCanvas resource is a IIIF resource presented simultaneously with the main resource, where a target of rendering is not IIIF-compatible and must be viewed outside the main resource’s viewer. In addition, accompanyingCanvas is used for content complementary to the main resource while rendering points to additional representations of the same resource.

  • rendering (IIIF Presentation API reference)
    Unlike seeAlso, the rendering property provides the URI of an alternate representation of the current resource, such as a PDF or ePub version. The type values for rendering vary more widely than do those for seeAlso, in keeping with the variety of target formats possible.

Any resource may have the seeAlso property. Each instance of it may have multiple items contained inside it, provided each has the id and type properties; label, format, and profile are strongly recommended properties. Conforming clients may process this property in some way, but the outcomes of a client’s processing has no defined form.




In this example, a MODS XML file is provided for the program as a whole, and as such the seeAlso property attaches to the Manifest. If such data files were available for each view or page separately, each Canvas would be a logical place for the corresponding seeAlso instance.

To see the property in action in Mirador, toggle the sidebar by activating the three-line (“hamburger”) menu in the upper left-hand corner of the content window. You should then, in the “Related” area, see the link in the “Related” section under the “See also” subheading.

JSON-LD | View in Mirador | View in Annona | View in Clover

The direct link to the fixture is a useful convenience.