Estimating the urban expansion and heterogeneity of a metropolitan region: a case of Kolkata metropolitan area

Urban planners study development patterns along with the rate and type of urban expansion to formulate policies and schemes for planned and integrated future deve­lopment of the cities. This study aimed to explore the dynamics of urban sprawl in the metropolitan region of Kolkata by using Gini–Simpson’s diversity index. It was used on the generated decadal maps to understand the degree of spatial concentration or dispersion of the built areas. It revealed that the urban sprawl was increasing in the outskirts of the Kolkata metropolitan area (KMA) with gradual dispersion and increased heterogeneity. A better understanding of the spatial and temporal dynamics of the city’s growth, provided by this study, forms the basis for better planning and effective spatial organization of urban activities for the future development of KMA.