Transition of Urban Morphology in the Mountainous Areas Since Early-Modern Times from the Perspective of Urban Historic Landscape—A GIS Tools and Historical Map Translation Approach

Regenerating cities must blend modernization and heritage. Both urban morphology and Historic Urban Landscape (HUL) highlight historical processes and may assist in regeneration. Using Chongqing as the study example may further understand mountain cities, which are prevalent worldwide but seldom examined in morphology research. This study explores and organizes the historical modernization of Chongqing’s parent city from early-modern times to the present day using a universal approach established in this research developed by the HUL perspective and research framework, Geographic information system (GIS), Depthmap tool, and historical map translation method. Large-scale modernization occurred prior to the 1980s, followed by more modest rehabilitation projects. The whole procedure is described by the phrase “Construction first, then planning, then transformation,” which entails a “free growth” block structure at the outset, along with planning control. The study contributes the following: (1) Establishing a theoretical framework and research technique for the universal city based on historical sources and modern instruments; (2) Chongqing’s future sustainable development and historical preservation depend in large part on figuring out the city’s complicated modernization history; (3) The study of mountain cities may benefit from understanding the geographical development and spatial dynamic layering of Chongqing. (4) This study bridges the gap in time by going beyond the early modern period covered by the previous ones and into the post-statehood era (1949–2022).