From accessibility of traffic to accessibility of service: the spatial analysis of N-minute service circle of urban park system

As an important strategy of basic public services in China, service "accessibility" follows the concept of fair and equal public services. Compared with the traditional transportation accessibility, it is also a comprehensive consideration from the dimension of residents' demand and service supply to promote the balance of urban park space layout and service coverage. Based on the N-minute service circle, this study establishes a comprehensive evaluation index system to quantitatively assess the service balance of urban parks based on three dimensions of service availability, spatial balance and social equity, taking the Shangcheng District of Hangzhou as an example. And further, an optimization model of urban park system is constructed to carry out spatial analysis and optimal adaptation of urban park system by combining residents' demand and evaluation. The results show that the overall accessibility of urban park services shows a spatial pattern of "high in the north and low in the middle", with obvious spatial differentiation along the river area. The urban park system optimized by the model based on the assessment results achieves the "accessibility" and "refined" quality of urban park services. Meanwhile, this study provides a reference for building a more all-age and quality urban park system.