In 1973, NASA and United States Geological Survey's Landsat 3 satellite took the image above of quiet, rural land (plant-covered land is red) along China's Pearl River Delta. Six years later, in 1979, the region began to grow as China set up two economic zones north of Hong Kong. Then, 30 years later, in 2003, Landsat 7 satellite took this dramatic shot:
It's a surreal urban shift. You can see the booming urban areas in gray, a major contrast to the mostly red image from 1973. In the image you can see part of Guangzhou, the most populous urban area in the region today with 12,700,000 people; Dongguan, an urban area with more than 8 million people; and Foshan with more than 7 million. As of 2010, the Pearl District Economic Zone had a population of 36 million.
The images are part of an interactive feature from NASA and the USGS to celebrate 40 years of the Landsat satellite capturing images of Earth. You can see more before and after images from 10 other cities across the globe. Or, at The Atlantic Cities, check out Nate Berg's slightly jarring animated GIF rendition of the urban shift.
This post was originally published on Smartplanet.com