[iheartthed]

Originally Posted by kittyhawk28

Even still, you probably should not merge the two cities. It makes no sense, they have separate centers of gravity at the end of the day. An analogous argument would be LA and SD, where you can take a a Metrolink commuter train to Oceanside then transfer onto San Diego's Coaster/Sprinter trains, as well as the two metros having contiguous urbanization along the I-15 corridor. It doesn't change the fact that, at the end of the day, they are two cities with separate and distant centers of gravity, linked only tenuously by some spillovers on the fringes of their metro areas. No sane person would consider them one, even if they share deep economic, cultural, and transport links. Same with NY/Philly, just because they share some spillover, doesn't mean you can call them a single metro. Unless, that is, you are fine with classifying the whole of Japan, UK, and the Blue Banana as a contiguous urbanized metro if applying the same density thresholds used to class NYC and Philly as one. Just because you can, doesn't mean you should.

The line between L.A. and S.D. is pretty clear, while the line between NY and Philadelphia is extremely arbitrary.