The physical face of slums: a structural comparison of slums in Mumbai, India, based on remotely sensed data

The term "slum" is difficult to define, but if we see one, we know it. Definitions for slums are qualitative such as "areas of people lacking, for example, durable housing or easy access to safe water". This study aims at identifying characteristic physical features of the built environment that allows defining slum areas based on quantitative and measurable parameters. In general, spatial data on slums are generalized, outdated, or even nonexistent. The bird's eye view of remotely sensed data is capable to provide an independent, area-wide spatial overview, to capture the complex morphological pattern and at the same time capture the large-scale individual objects typical for slums. Using high-resolution optical satellite data, parameters such as building density, building heights, and sizes are used to differentiate between slums and formal settlements. From it, the physical features are used to analyze structural homogeneity and heterogeneities within and across slums and to suggest characteristic physical features for spatial slum delineation at three study sites in Mumbai, India.