Abstract
Rapid rates of population growth and urban expansion affect local and regional ecosystems, climate, and biogeochemistry. Ninety percent of future urbanization will be in low-income countries. In many low-income regions of the world, the only up to date maps of urban extents are those produced on a global scale. However, in some regions such as East Asia, urban expansion is proceeding so rapidly that only a few years can make a large difference on the ground. Therefore maps of settlement in low-income countries are often outdated, inaccurate or non-existent. This research improves our understanding of the methodological and validation requirements for global urban mapping from low-resolution remote sensing data. Maps derived thereby are then compared against urban boundaries derived from Landsat ETM+ imagery and the other five continental scale urban maps. Maps produced using gridded population density data, nighttime lights and MODIS data use less costly data and are simpler to produce yet proved to be more accurate.
