Look into the past with this scratch-off map of Brooklyn

A new project from CartoDB’s Chris Whong goes to the heart of how mapmaking can show a lot more than just where things are in space.
Whong was thinking about the changes to the landscape brought upon by the behemoth BQE, 35.62 miles of interstate highway that carve up Brooklyn just inland from the waterfront, a road he drives on each day from his house in Red Hook to CartoDB’s office in Bushwick.
“I’m always interested in the scars left on the built environment by interruptions to street grids, widening of roads, landfill into water, etc.” Whong wrote in a post about his map. “The idea popped into my head that it would be really interesting to ‘erase’ the pre-BQE blocks on a historic photo to reveal the modern highway and get a better idea of the cost of progress. To be honest, it reminded me of SimCity, where you can demolish whole swaths of land with a click of a mouse.”
Robert Moses also gets a shoutout in the blog post. (Editor’s note: Go read The Power Broker.)
The result of his work, Urban Scratchoff, is a map with two layers: present-day aerials and 1924 aerials (the BQE was originally planned in 1936, though not completed in its entirety until 1964). By clicking on a point in the map and dragging, you can clear away the years and see how the same territory looked in 1924. You can also reverse it and drag through 1924 to see what the present day looks like.
See the map
On the whole, not a lot has changed. The BQE is probably the biggest thing, and there are definitely fewer wharves on the river.
Whong used map data from the New York Public Library’s very cool crowdsourced Map Warper tool. He’s placed the code for the project on GitHub, so if anyone has questions or suggestions, check that out.