This morning we looked at the Croton Reservoir, where the New York Public Library's main branch now sits. In the time that it's been there—since the early 1900s—the surface of New York City has continued to change. Luckily, the library is home to a massive collection of maps, which chart the changes of this city as well as other areas—and this week they've officially launched maps.nypl.org. The site also hosts "a powerful set of tools designed to significantly enhance the way we access and use maps and the cartographic information they contain." Click! Zoom! Pan!
So learn more about the georectification, or “warping" process (tutorial after the jump) and make some cool maps! Anyone can participate by creating an account on the site.