Call us. (Photo: BBC)

Ever stood on a street corner wondering what your neighborhood looked like a century ago? If yes, a) you are a nerd and b) the New York Public Library is working on it.

Thanks to a 2010 grant from the National Endowment for the Humanities, the NYPL has embarked on a big effort to digitize its collection of historical maps. And for the history-crazed among us, they've just posted a lengthy, detailed description of how that project works.

You might assume that digitizing a map collection is as simple as scanning the paper versions and slapping them on the open web. Not the case. In order to be useful, the maps must be "georectified," or aligned with their modern virtual equivalents. (If that sounds interesting, good news: The NYPL is crowdsourcing that part of the project, which means you are more than welcome to pitch in.) The result is something that looks like this 1909 map of Queens, which has been lined up nicely with the modern grid in case you'd maybe like to look up your apartment like we just did.

The next step after that is cropping (removing those snazzy, flowery borders so many 19th century documents have). Last comes digitization, which is really a step called map tracing, which is "preparing machine readable data to be harvested, mined, analyzed, mashed, made part of the semantic web and relate to itself, across time." And that's going to make walking tours a lot more awesome:

This type of data will eventually allow you to ask your phone a question like, "I'm standing in front of the Coney Island Cyclone, what other attractions would I see if I was here 100 years ago?" and be presented with a reasonable answer such as, "on the other side of the street you'd see the colossal elephant bazaar that stood from 1885 to 1896, etc..."

So if you were to, let's say, hop in a time machine with a goofy Brit in a bow tie, you'd have a travel guide.

Just saying.