Caption: A new study of global urbanization, by Annemarie Schneider of the University of Wisconsin-Madison, finds that cities may occupy less land than previous estimates. Images show estimates for the greater metropolitan area of Guangzhou, China, whose current population is estimated at 13.9 million. Schneider's analysis (left) was based on detailed satellite data collected in 2001, and depicts the built-up land area. Right image shows an analysis based on circa 2000 population estimates from the Global Rural-Urban Mapping Project's 1-kilometer dataset.
Photo: courtesy Annemarie Schneider
Date: 2009
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