Retrofit-Oriented Large Parks’ Walking-Shed Evaluation—A Case Study of Rizhao, China

Large parks play a key role in the identity of urban public spaces and as destinations for residents’ urban walks, with the social benefits they provide being irreplaceable by other types of green spaces. This study examines the accessibility of large urban parks in Rizhao, China, focusing on spatial distribution, service equity, and optimization strategies. Using GIS-based walking route proximity analysis, the study identifies significant accessibility gaps in high-density urban areas. Rizhao is a typical coastal tourist city, selected as the study area due to its low level of urbanization and the underutilization of its natural resources. This study uses online map data to evaluate the service efficiency and supply–demand heterogeneity of large parks from multiple perspectives, proposing targeted, practical, and micro-intervention-based spatial measures based on typical case analysis. The results show that 70.52% of the population in the study area is served by park entrances within a 1500 m walking distance, indicating that a considerable portion of residents remain beyond a reasonable walking distance. In the context of urban renewal and sustainable development, this study proposes practical improvements to park accessibility, including suggestions for determining suitable locations for new large parks as a long-term goal, alongside low-cost interventions such as increasing park entrances to maximize the use of existing resources and optimizing pedestrian routes (including opening gated communities and adding crossing facilities) to improve park walking service catchment in smaller environments. This study provides insights for urban park renewal, retrofitting, and expansion, supporting accessibility measures in planning practices, and is expected to provide valuable references for urban managers and policymakers. Furthermore, the study suggests that policy adjustments are necessary to integrate green spaces into urban development more effectively, particularly in rapidly urbanizing areas.