From evaluation to planning: integrating quantity–quality in the spatial equity assessment and optimization of urban green spaces

Abstract Spatial equity in urban green spaces (UGS) is pivotal for enhancing residents’ well-being and promoting sustainable urban development. However, existing studies primarily emphasize the quantity dimension while neglecting the quality dimension and failing to establish dynamic linkages between assessment outcomes and planning practices. Using Xianyang’s central city as a case study, this research develops an equity-oriented UGS planning framework that integrates an enhanced Gaussian-based two-step floating catchment area (Ga2SFCA) method, Lorenz curve and Gini coefficient analysis, spatial autocorrelation, and multi-scenario optimization. The results reveal that the UGS spatial equity index in Xianyang exhibits a core-periphery gradient with axial extension characteristics, indicating pronounced inequity in spatial resource allocation. Synergistic strategies—combining stock optimization (optimizing existing UGS) with incremental expansion (developing new UGS)—effectively mitigate equity dilemmas through Pareto-efficient solutions. By integrating a two-dimensional assessment model encompassing both quantity and quality, this study advances the evaluation paradigm from a quantity-oriented approach to a quantity-quality integrated approach. The proposed equity-oriented multi-scenario optimization pathway establishes a robust linkage between evaluation and planning, providing theoretical foundations and practical guidelines for the equitable development of UGS.