Google maps on the iPhone is incredibly useful. However, at times, there are things it just doesn’t map: like the New York subway system, for example. Hats off to Khoi Vinh for coming up with clever hack to solving this dilemma for someone like me, who uses the subway on my frequent visits to New York, but not enough to feel confident without having access to a map. Using an idea he learned from Mikd Essl, he’s created and is sharing a series of sectional screen-grabs of a New York subway map one can upload and use in iPhone’s Photo application. The thumbnail feature of the Photo application and the “surprising logical interaction” of the iPhone’s photo scanning features make the maps work. Not elegant, but, as Khoi says, “They’re the most awesome low-tech New York City subway maps for your iPhone that you can find anywhere.” One of his commentors has observed that the New York MTA has sent cease and desist orders to others who have messed with their maps, so, download Khoi’s photos fast.