The NYC Space/Time Directory: Building the Future of NYC’s Past

By NYPL Staff
April 7, 2017


Two years ago, we had a crazy idea: what if we could make the maps of New York City’s past work like the maps of today? Could we create, for example, a searchable atlas stitched together from the pages of old maps—like Google Maps, but with a time slider? A location directory that helps you find historical place names, streets and addresses? A new way to discover our collections in historical and geographic context?

Talman Street, no. 57, Brooklyn

Brooklyn’s Talman Street in 1936, demolished for the construction of the Brooklyn-Queens Expressway. Image ID: 482809

As we thought about it more, we realized that maybe this idea wasn’t so crazy; the Library’s collections, after all, contain all the materials needed—maps, photographs, business directories, census data, oral histories, even menus—to create such a system. Whereas in the past you had to come to the Library in person and schedule an appointment to view all these materials, it’s now possible to browse hundreds of thousands of them online, digitized, in high resolution in our Digital Collections. And we didn’t stop there: items in Digital Collections are still just images, you cannot search their content—labels on maps, names and addresses in city directories or the locations where photos were taken. With online crowdsourcing tools like What’s on the Menu? and Building Inspector, we have created ways to extract information from our collections and turn them into data, for everyone to use.

Only one thing is missing: a system which links all these collections and their data, and makes them searchable and accessible through space and time.

[Map bounded by 12th St., Ashburn St., Newtown Creek, East River]

Long Island City in 1913; more railroad tracks and less luxury condominiums. Image ID: 1954547

The NYC Space/Time Directory

Thanks to generous funding from the John S. and James L. Knight Foundation, we were able to start designing and building this system: the NYC Space/Time Directory, a digital time-travel service for New York City, created using the collections of the Library.

Bringing the NYC Space/Time Directory to life is no easy task, and it won't happen all at once, so we'll be unveiling new tools and features as we develop them. Today we are excited to share with you the first fruits of our labor: Maps By Decade, and a new project website where we are publishing historical open data sets.

Maps by Decade

Maps by Decade is a new way to view more than 5,000 digitized street maps of New York City from our collection, published between 1850 and 1950. Over the past seven years, our librarians and patrons have used Map Warper to place more than ten thousand of our digitized historical maps on the correct location on a map of today’s New York by stretching and rotating them, a process which is called georectification.

With Maps by Decade, finding and viewing georectified maps is easier than ever. Use Maps by Decade to browse and compare the streets of New York City, one decade at a time. See how your neighborhood looked in a hundred years ago, and download maps in high resolution, most of which are available in the public domain.

Historical geospatial open data

Maps by Decade is built using a dataset containing the outlines and location of maps from Map Warper. This dataset, along with many others, can be downloaded from the website of the NYC Space/Time Directory. Historical buildings and addresses from Building Inspector, locations of historical street photography from OldNYC, 18th century ward boundaries: all this data, from different collections and research divisions or the NYPL, is now available in one place, and in one format.

dataset drawing

Dataset with outlines of Map Warper maps, visualized with QGIS

Currently, the NYC Space/Time Directory contains the following data:

  • 8,000 maps

  • 180,000 historical addresses and buildings

  • 40,000 georeferenced photos

  • 700 historical streets

  • 800 churches

Diagram showing how data is processed and published in the NYC Space/Time Directory

Stay in Touch

Over the coming months, more tools and datasets will be released, as well as tutorials and documentation on how to interact with the NYC Space/Time Directory. Keep an eye on the project’s website or follow NYPL on Twitter to stay up to date. Developers and others interested in the project’s source code can visit GitHub to browse the many open source repositories that make up the NYC Space/Time Directory.

The NYC Space/Time Directory also has its own meetup series: Historical Maps & Data at NYPL. Designers, coders, historians, genealogists, librarians and archivists alike, we're inviting everyone interested in the history of New York City to meet and listen to talks about historical data and the NYC  Space/Time Directory project. So far, we have organized two events: one on city directories and one on historical addresses and buildings; more will follow this spring, summer, and fall. As we schedule new meetups, they will be posted on the project's website and on

Do these datasets and tools help you with research? Explore our collections in new ways? Enable you to make a new app?  Or do you have any questions regarding our datasets? Let us know! We'd love to hear how you're using the NYC Space/Time Directory!