Urban Growth Mapping of Mega Cities: Multisensor Approach

Urban areas occupy a relatively small fraction of the earth’s land area, but at present more than half of the global population lives in urban areas, and this proportion is expected to increase in the coming decades (United Nations, 2014). Urban areas contribute significantly to climate change as a result of the use of fossil fuels for electricity generation, transportation, and industry. Already the intensive burning of carbon fuels in the world’s urban areas accounts for about 70% of global greenhouse gas emissions (Solecki et al., 2013). In addition, previous research suggests that a 10% increase in urban land cover in a country is associated with an increase of more than 11% in the country’s total CO₂ emissions (Angel et al., 2011). Urban form and structure are key factors that determine urban energy use and emissions, and urbanization fundamentally changes the urban form and urban spatial structure, including the number of buildings, their geometry, pattern, distribution, and density (Frolking et al., 2013).