Encyclopedia of Chicago

Preserving the Historical Context From a Great City's Past

The Encyclopedia of Chicago uses Fedora to manage rich historical content while maintaining its context and complexity. Holdings include web sites or collections in which the objects themselves are complex, or in which the relationships between objects are complex, and the presentation of these objects is varied that require consistent access. Fedora was chosen because there was no other digital asset management system that seemed "Future proof" --able to accommodate evolving technologies.

The Encyclopedia of Chicago is part of the Academic Technologies Group at Northwestern University where, there are two other Fedora projects. The first is a general deployment brought up for test purposes. This repository is used to test object models and is used for a class. In another project Chris Karr has set up a repository for a joint project between NWU-Academic Technologies, Michigan State University, the National Archives and Records Administration, Glasgow Caledonian University, and the BBC -- Information and Archives which will make digital audio archive materials available for use by students and faculty at the partner institutions.

In general, the Academic Technologies group has written middleware layers above the Fedora core software which interact with the Fedora APIs, including java programs that do bulk ingest and behaviors for images that drive zooming clients and allow users to retrieve specific parts of an image at a specific size.

For the Encyclopedia of Chicago repository specifically, which is built on Fedora and disseminates the repository objects as a web site for delivery to users, the Fedora objects have a range of object models, depending on the type of data being represented. The metadata datastreams in the data objects are Cocoon URLs, which act as an adapter to the mySQL database where the metadata is stored. These Cocoon URLs perform database queries on the mySQL database and produce XML. Disseminations vary in type. HTML disseminations are XSLT servlets operating on datastreams from the data object. More complex objects add to this scenario more relationship data, e.g. bound volume objects have relationship data pointing to objects that are page scans; map objects have relationship data that includes layers that can be turned on and off.