Characterising Urban Sprawl from Remote Sensing Data and Using Landscape Metrics

Urban sprawl refers to the outgrowth of urban areas caused by uncontrolled, uncoordinated and unplanned growth. This outgrowth seen along the periphery of cities, along highways, and along roads connecting a city, lacks basic amenities like sanitation, treated water supply, primary health centre, etc. as planners were unable to visualise such growth during planning, policy and decision-making. Sprawl generally infers to some type of uncoordinated development with impacts such as loss of agricultural land, open space and ecologically sensitive habitats in and around urban areas due to lack of integrated and holistic approaches in regional planning. In developing countries, where urbanisation rates are high, urban sprawl is a significant contributor of the land use change. However, characterising sprawl has become a contentious issue with numerous arguments both for and against the phenomenon. Meanwhile, effective metrics to characterise sprawl in India are required to characterise this. We have attempted to capture urban sprawl over the landscape and hence adopt landscape metrics for characterising sprawl. We further ascribe that prevalence of sprawl leads to erosion of landscape elements. The satellite remote sensing data for Bangalore, India, of Landsat TM and Landsat ETM+ for 1992 and 2000, were used and through a multi-stage classification process, post-classification change detection was performed. Bangalore city is popularly known as ‘the garden city’ of India is experiencing rapid urban growth and consequent to the software boom, the city is now referred as ‘IT Capital’ of India. The growth Bangalore is experiencing has significant implications on land use. The landscape metrics adopted were computed and the compared for these two time-periods to characterise sprawl. It was evident from these metrics the amount of dispersion and dispersed growth taking place in radial direction across Bangalore. The study demonstrates the utility of using landscape metrics for characterising urban sprawl.