Urban growth trend analysis of proposed Greater Silchar City, India, using landscape metrics and Shannon entropy model

Most cities in the world suffer from excessive population and unplanned urban growth. The objective of the present study was to investigate the spatiotemporal changes of built-up areas and their growth in the proposed Greater Silchar City (GSC) (Assam, India). The obtained LANDSAT satellite data from 1991 to 2021 for the GSC have divided into non-built-up and built-up land use categories, and recode tools in Erdas Imagine 2014 software have been used to improve the accuracy of the output. The study area has been classified into 8 spatial directions and 11 concentric circles with radial distances of 1 km and resulted from intersected areas consisting of 60 gradient zones. The study used Shannon entropy model for detailed urban sprawl study of every nook and corner. FRAGSTATS v4.2 tools have been used to analyse landscape metrics in respective spatial directions. The built-up area growth of the city was 15.18 km(2) during the mentioned period. The landscape metrics and LU/LC results show the maximum built-up growth has taken place in South to South-West direction (3243.87 ha) and the area within a 2-3-km radius (221.85 ha) of the central business district, which is the periphery of the existing Silchar municipal limits. The entropy values indicated that the GSC has compacted infill growth form in the core area, while the dispersed urban sprawl trends followed with increasing distance from the city centre. Moreover, the research findings will provide a conceptual model for assessing urban growth trends for other cities as well.