When astronauts photograph cities at night, the pattern of lights often hint at the influence of terrain on urban growth. Lights stop abruptly at unseen barriers that could be rivers, oceans, or mountain ridges. This image of the Los Angeles metropolitan area shows the topographic details that are often hidden in the darkness.
In this image, an astronaut photograph of the Los Angeles area is overlaid on a topographic image made from the United States Geological Survey National Elevation Dataset (1 arcsecond resolution). The grid of streets is outlined by orange (sodium vapor) and blue-green (mercury vapor) lights. The airport, the naval docks, and downtown LA are especially bright.
Several mountain ranges interrupt the expanse of lights. The Chino Hills split the southward expansion of the city, with Orange County on the west and Riverside County on the east. The Santa Monica Mountains corral the suburbs to the west. The suburbs on the Palos Verdes Peninsula in the foreground are darker than other parts of the scene, with the lights of the Peninsula Center as the brightest exception. The astronaut photo was taken shortly after 1 a.m. local (Pacific) time on March 10, 2003.