At the University of Michigan’s Hatcher library, the latest expansion to the collection is happening within a 12 × 20 windowless room housing several servers. The digital archivists on the Digital Map Library team are working to scan the library’s entire extensive collection of maps, in order to “bring geographical history into a more modern perspective,” says lead archivist Natalie Bond. “We want the Michigan DML to become the first and best resource for historical maps, and we want it to be accessible to any library in the world.”

High resolution scans create enormous files, usually in the realm of 4,500 megabytes for just the initial layer. The DML team then adds additional layers of metadata and imagery to make the maps interactive — and searchable. “By the time we’re done, each map is made up of hundreds of separate files. If you had to load it all at once on your browser, you’d be waiting all day; it’s around 1,500,000 kb even after some of the image compression. So we’ve developed a way to load the data in a way that’s much easier for people to actually use.”

The library’s collection of over 30,000 original maps is about 40% scanned at this point, by Bond’s estimate. The project is on its second year of funding, with four years approved in total. Bond is already looking beyond that, though. “We’re also talking to groups like the National Archives and NDIIPP (National Digital Information Infrastructure and Preservation Program) about how to make this a wider effort, beyond just the university.”