Changes in urban built-up surface and population distribution patterns during 1986-1999: A case study of Cairo, Egypt

Landsat TM and ETM+ images were used to examine urban growth for the Greater Cairo area, Egypt, between 1986 and 1999, assisted by fieldwork and high spatial resolution images such as IRS, CORONA, and IKONOS. During the study period, urban land (collectively classified as built-up surface) increased significantly. Most of the increases in urban land came from the conversion of desert land and farmland on the Nile Delta. When changes in built-up surface were analyzed against census data of 1986 and 1996, it was found that population per unit area of built-up surface may serve as a good indicator of urbanization. This metric offers a different measure from the traditional calculation of population density and provides a measure of urban living environment by reflecting the dynamics of both population and urban land use growth. For the entire study area, population density increased by 26.8% from 7158 persons/km2 to 9074 persons/km2 during 1986-1999. In the mean time, the total built-up area increased by 33.7% from 344.4 km2 to 460.4 km2, while population per unit of urban land decreased from 27,188 persons/km2 to 25,799 persons/km2, indicating that urban land use growth in terms of construction and infrastructure may have outpaced population growth in Cairo overall. However, such changes were not evenly distributed. While most increases in built-up surface were found in the outer margin of the greater Cairo area, population per unit built-up area increased most significantly in the suburbs and to the south of the city. Such changes reflected the nature of housing demand and the mechanisms that governed the urbanization process in the Greater Cairo area.