Assessment of urban sprawl characteristics in Indian cities using remote sensing: case studies of Patna, Ranchi, and Srinagar

The rapid urban growth in mid-sized cities of developing nations has induced conflict between development and the environment, often leading to urban sprawl. However, studies focusing on the assessment of urban sprawl in mid-sized cities are comparatively rare. Therefore, this paper assesses the spatio-temporal urban sprawl characteristics of three typical mid-sized Indian cities, such as Patna Urban Agglomeration (UA), Ranchi UA, and Srinagar UA, from 1991 to 2018 using Landsat images. The population density, landscape metrics, and urban expansion index were employed to detect and assess urban sprawl characteristics. A multivariable integrated urban sprawl index was computed using Z-score to examine the intensity of urban sprawl. The results revealed robust evidence of the built-up growth in all three cities. The rise in built-up was observed due to the conversion of fallow and agriculture land covers in Patna UA and Ranchi UA, while water body and fallow land covers in Srinagar UA. Despite an increase in the total population and built-up, population density declined in all three cities. The analysis using landscape metrics exhibited continuous outward expansion with an increase in shape irregularity of built-up patches. The urban expansion index indicated the prevalence of edge expansion typology of urban sprawl. Patna UA exhibited the highest intensity of urban sprawl as per the multivariable integrated urban sprawl index. The obtained results will benefit the urban planners and officials to promote urban sustenance by preparing relevant strategies under the Smart City Mission. This study demonstrated an effective utilization of scientific approaches to assess urban sprawl characteristics in mid-sized cities.