Comparative evaluation between Shannon's entropy and spatial metrics in exploring the spatiotemporal dynamics of urban morphology: a case study of Prayagraj City, India (1988-2018)

This study aims to explore transformations of urban morphology in an Indian city, Prayagraj because it widely unexplored. This work is examined by Shannon's entropy, relative entropy, density index, and spatial metrics [percentage of landscape (PLAND), number of patches (NP), and patch density (PD)] to evaluate the state of compactness or, dispersion over the landscape in the study area. The built-up growth has shown increased from 25.385 to 98.942 km(2) during 1988-2018. Shannon's entropy results are indicating enlargement of urban sprawl from 1.48 to 1.77 during 1988-2018. Relative entropy results are found dispersed growth in 1988 (i.e., 0.594) to compact growth in 2018 (i.e., 0.246). Density index has shown drastic growth in core city (0-6 km) during 1988-2018. Spatial metrics results are showed growth of 16.26% in PLAND, 11507 in NP, and 2543.634 in PD during 1988-2018 respectively. While mean PLAND has shown that growth has been declining from city center to Zone-6 in 1988, 1997, 2008, and 2018. The mean NP, and mean PD profiling results have shown a reverse trend to mean PLAND in said time points. But urban growth has concentrated highly on city center to Zone-4 (0-8 km) in compacting mode and lowly on Zone-4 to Zone-6 (8-12 km) in dispersion mode. Therefore, 0-8 km area requires more emphasis on policy making within sustainable sphere thinking while 8-12 km area relatively needs more attentions for controlling measures for future urban planning.