Assessing the paradox between development and preservation: A study on the coupling and coordination degree of morphology, function, and behavior in historic districts

The paradox between historic preservation and urban development poses a significant challenge to the sustainable revitalization of historic districts. This study proposes a quantitative and spatially explicit framework that combines diachronic analysis of historic street morphology with a coupling coordination degree (CCD) model, Multiscale Geographically Weighted Regression (MGWR) and GeoDetector. Using Old Chengnan in Nanjing as a case, we trace the long-term evolution of urban form and assess resident-oriented and tourist-oriented CCD at the street scale based on the coordination among morphology, functions and behavior. MGWR and GeoDetector are used to further identify the dominant factors and interaction mechanisms shaping CCD variation. The results show that resident-oriented CCD is shaped locally by the density of resident-serving functions, while its broader spatial differentiation is driven mainly by everyday activity intensity and its interaction with street structure. Tourist-oriented CCD is dominated by tourism-supportive functional density and strengthened by function–behavior interactions. Overall, the proposed framework provides methodological and practical insights for balancing the sustainable development needs of residents and tourists in Chinese historic districts. • A framework for assessing the preservation–development paradox in historic districts. • Quantified CCD between spatial morphology, functions, and user behaviors. • Reveals divergent drivers for resident-oriented and tourist-oriented.