You’d think it’d be relatively hard to mislay a city. Cities are, by definition, very large things: losing one sounds like it should be much more challenging than losing, say, your car keys, or even your entire car.
But in China, there are entire cities which go relatively unaccounted for. This is the result of a combination of fast development, low regulation, and the fact that many Chinese cities are still practically empty.
This is why it’s pretty hard to get a figure for just how many “ghost cities” – cities that exist, but lack residents – there are in China. Most of these cities have some residents, making “ghost” a relative, and pretty hard to define, term.
So Baidu (basically, China’s Google) decided to work it out. The researchers behind a new study, “Ghost Cities: Analysis Based on Positioning Data in China“, used location data from users’ phones, plus mapping and building location data, to find areas with high volume of buildings, but a low density of people. The researchers also tried to discount vacant areas that were empty because of tourism: apartments only filled in high tourism season, for example.