A Schneider et al 2009 Environ. Res. Lett. 4 044003 doi:10.1088/1748-9326/4/4/044003
A Schneider1, M A Friedl2 and D Potere3
Show affiliationsAlthough only a small percentage of global land cover, urban areas significantly alter climate, biogeochemistry, and hydrology at local, regional, and global scales. To understand the impact of urban areas on these processes, high quality, regularly updated information on the urban environment—including maps that monitor location and extent—is essential. Here we present results from efforts to map the global distribution of urban land use at 500 m spatial resolution using remotely sensed data from the Moderate Resolution Imaging Spectroradiometer (MODIS). Our approach uses a supervised decision tree classification algorithm that we process using region-specific parameters. An accuracy assessment based on sites from a stratified random sample of 140 cities shows that the new map has an overall accuracy of 93% (k = 0.65) at the pixel level and a high level of agreement at the city scale (R2 = 0.90). Our results (available at http://sage.wisc.edu/urbanenvironment.html) also reveal that the land footprint of cities occupies less than 0.5% of the Earth's total land area.
91.90.+p Other topics in solid Earth physics (restricted to new topics in section 91)
91.10.Jf Topography; geometric observations
93.85.Bc Computational methods and data processing, data acquisition and storage
Issue 4 (October-December 2009)
Received 14 February 2009, accepted for publication 21 September 2009
Published 12 October 2009
A Schneider et al 2009 Environ. Res. Lett. 4 044003
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