You might think of libraries as musty shrines to dead tree technology, visited mainly by school groups, middle-aged public radio subscribers, and passersby in need of a restroom. In some cases you might be right. But the New York Public Library is doing some creative things to make its vast collections more relevant in the digital age.

"This place is a Victorian steampunk internet," the library's David Riordan told me when I visited last month. Riordan is a project manager for NYPL Labs, a technology and design unit created in 2011 to boost the library's presence on the actual internet. The goal is to move beyond simply scanning the library's collections and putting them online, says NYPL Labs manager Ben Vershbow. "We want to put these materials into all sorts of conversations that the digital medium makes possible."

The Labs' latest effort is a game called Building Inspector that allows you to play around with digitized fire insurance maps of New York City from the 1850s and 1860s and improve the accuracy of the digital versions in the process. It's not technically an app, but rather a website developed to work well on smartphones in hopes that people will fix a few maps while they're stuck waiting in line or on the subway.

The red outline around the Piano Forte Manufactory building looks about right in this Building Inspector screenshot. (Lionel Pincus & Princess Firyal Map Division, NYPL)

Building Inspector isn't likely to keep you up all night in an obsessive frenzy, but it's fun enough to kill a few otherwise-wasted minutes here and there. It shows you a zoomed in view of the atlas, and your job as inspector is to make sure a dotted red line around one of the buildings is accurately positioned. (Click the help button for a tutorial before you start). If it's not right, you can flag it to be fixed. "To start we made it pretty simple," Vershbow said. "Eventually we might have to think about gamification."

What is the point of picking building footprints out of old maps? Well, it's part of a bigger strategy to make the library's awesome collection of maps a gateway into its other collections. "If you have a building, that's a backbone of data you could hang other stuff on," Vershbow said. That could include things like events that occurred there, gleaned from newspaper reports, or the people and businesses that resided there, extracted from old city and business directories.

When you start stringing those pieces of data together, some interesting stories can emerge. At a recent Map Hack hosted by the library, data scientist and mapmaker Andrew Hill of Vizzuality used the library's collections to begin reconstructing the life story of one interesting New York resident in the mid-19th century.

But what Vershbow and his colleagues – including geospatial librarian Matt Knutzen – want to do is build a digital toolkit that will allow even people without special expertise to do things like this.

The first of these tools is something called the Map Warper. Developed a few years ago by the library, Map Warper is a web-based tool for georectifying scanned historic maps so that they can be aligned with modern maps like Google Earth (see below) or OpenStreetMap. So far about 5,000 maps have been georectified, Knutzen says. Anyone with an internet connection can use it, but most of the work so far has been done by library staff, organized student groups, and volunteers who come to citizen cartography days hosted by the library.

But scanning and georectifying old maps only gets you so far. There's lots of other useful information on maps, such as street names, addresses, and in the case of the fire insurance maps, building footprints and information about construction materials. Until recently all this information had to be entered by hand, which is excruciatingly tedious. (The atlas currently available in Building Inspector, for example, includes 61,000 buildings in Manhattan).

Over the summer, NYPL Labs' interactive designer Mauricio Giraldo developed a computer vision workflow that makes quick work of one step in this process: extracting the footprints of individual buildings. Giraldo wrote a Python script that ties together a bunch of open source image processing programs. It's called the Vectorizer, and it's available on GitHub. The Vectorizer can extract about 150,000 building footprints a day from a fire insurance map, Giraldo says. By comparison, it took NYPL staff and volunteers two years to extract 170,000 footprints (and some additional metadata) from four atlases in the library's collection.

Alas, like all computer vision apps, the Vectorizer is no match for the human brain. And that's where Building Inspector__ __comes in – it's a way to do quality control by getting a whole bunch of people to each do a little bit of work fixing the Vectorizer's mistakes. "It's a computer-human collaboration," Vershbow said. "It's like a reCAPTCHA for urban maps."

Great. So let's say you've scanned and georectified some old maps, extracted the building footprints and other data, and done quality control. Then what?

Now it's time to start connecting the map data with other data from the library's collection and elsewhere. Thanks to a grant from the National Endowment for the Humanities, NYPL is already working on a foundation for doing that, a gazetteer they're calling New York City Chronology of Place. It's still very much in development, but eventually it will allow you – or at least this is the vision – to type in an address or the name of a building in New York City and slide a bar to pick a time period. Your location will appear on a georectified map from that time, and from right there on the map you'll be able to access historic photos, restaurant menus, phonebook entries, building permits, census records, and who knows what other resources from the library's collections and elsewhere.

To imagine how this might be useful, Knutzen says, consider a writer working on a novel set in 19th century New York. Instead of having to run around the library from one collection to another, she could log onto the gazetteer and access a wealth of information about what a given neighborhood was like at a given time. "Was this a cool place to be? Who lived here? Would you get jumped, and what would they call it back then to get jumped?"

"Our maps could become the means by which all that other information is wrangled," Knutzen said. "We just need to create the digital glue that holds it all together."