From Fortified Settlement to Metropolitan Region: Mapping the Spatial Evolution of a Historic South Asian City

Abstract

Historic cities across South Asia have experienced substantial spatial transformations as fortified settlements gradually expanded into large metropolitan regions under the influence of demographic growth, infrastructure development, and changing land-use patterns. Understanding these long-term urban dynamics is essential for sustainable planning and heritage conservation. This study reconstructed the historical spatial evolution of a representative historic South Asian city using Geographic Information System (GIS)-based analysis integrated with historical maps, satellite imagery, administrative boundaries, and land-use datasets. Geospatial processing techniques, including georeferencing, digitization, spatial overlay, buffer analysis, and urban morphological assessment, were employed to quantify changes in urban extent, land-use transformation, and metropolitan growth. The results revealed a continuous increase in built-up area accompanied by a substantial decline in agricultural land, reflecting the gradual transition from a compact fortified settlement to a polycentric metropolitan structure. Transportation infrastructure and administrative expansion were identified as the primary drivers of urban growth, while morphological indices indicated increasing spatial complexity and outward expansion over successive development phases. The integration of historical GIS with quantitative spatial analysis provided a comprehensive understanding of long-term urban transformation and highlighted the persistence of the historic core within the contemporary metropolitan landscape. The study demonstrates the effectiveness of GIS for reconstructing historical urban evolution and offers a transferable analytical framework to support heritage preservation, sustainable metropolitan planning, and evidence-based urban policy for historic cities across South Asia.