In the last few years astronauts at the International Space Station have been producing an  extraordinary collection of images showing large cities at night. Surprisingly, they often show different patterns from the ones shown in maps of even daylight satellite images.

For example, the foundational north-south axis of Beijing (north is at the top-right corner in the image) is barely apparent, while the east-west line of Chang'an Avenue becomes dominant in the night image. you can recognize it particularly in the center where is brighter and thicker, with elongated rectangle of Tian'anment Square to the south. The image shows the concentric ring structure very clearly, all the way to the 6th Ring Road more than 10 miles away from the center.

But the night view shows another urban pattern emerging, with a series of radial extensions, almost as if they were the legs of a spider. Not so much to the west and north where growth is limited by the Xishan and Yanshan ranges but certainly to the east and south, as the city seems to be on its way to connect with the cities of Lanfang and Tianjing, all the way to the to the sea port on Bohai Bay.

(By the way, the combined population of the three cities is currently something like 40 million, so allowing for even a modest growth we will be soon looking at an urban agglomeration topping 50 million people!)