“…New approaches to collecting consistently defined data over wide geographic areas on urban form, size, and population. Efforts are underway using administrative units (Tobler, Deichmann, Gottsegen, & Maloy, 1997;UNEP, 2002), satellite data (Dobson, Bright, Coleman, Durfee, & Worley, 2000), and the distribution of nighttime lights (Elvidge, Baugh, Kihn, Kroehl, & Davis, 1997;Pozzi, Small, & Yetman, 2003). For example, CIESIN's Global Rural Urban Mapping Project has developed a globally consistent map of urban extents (polygons) and urban populations for cities with populations greater than 5,000 (O'Neill & Balk, 2001).…”