Analyzing Urban Growth Dynamics Over Sixteen Major Indian Cities Using IRS and Sentinel Satellite Observations

Abstract

Urbanization in Indian megacities is pacing at an unparalleled and irreversible rate (31.1%). The current study focused on analyzing the growth dynamics of sixteen major Indian cities having population above one million. Rise in population corresponds to the increasing demand for land resulting in abrupt growth of the city known as sprawling. Land Use Land Cover (LULC) thematic datasets were acquired from ISRO (IRS data) and ESRI (Sentinel data) for 2005, 2010, 2015 and 2021 for the study. The variability of the five LULC classes viz., urban built-up, vegetation, water body, agriculture and barren land indicated that urban expansion mostly took place at the expense of barren lands. The urban landscape of Indian cities mostly depicts dispersive outward growth since the beginning of the 21st century with significant amount of compaction near the Central Business District (CBD) in the recent years. The results derived through Shannon’s Entropy (SE) approach, various Spatial Metrics and urban density gradient analysis have also indicated the same. SE values nearing ln(n) indicates dispersion away from the CBD (maximum observed in Bhubaneshwar-Cuttack urban agglomeration i.e., ~1.702 in 2021). Spatial metrics like Patch Density, Contagion Index, Diversity Index, etc., and urban density gradient analysis have further confirmed the compaction of cities near the CBD (~95% within 5 km), and gradual decrease thereafter. Additionally, the morphology associated with the cities, influences the direction of city growth just like the course of river Hooghly dictates Kolkata’s urban expansion. Population density compared with urban expansion indicates that both are proportional to each other (e.g., Pune exhibited ~83% increase in urban area corresponding to ~47% increase in population density). Thus, the derived results offer vital information regarding the existing patterns of urbanization and hence could be of use to city planners for better management of resources while building a sustainable city.