Integrating multimodal accessibility and spatial morphology to assess urban green space equity: evidence from Fuzhou, China

With accelerating urbanization, equitable access to urban green space (UGS) has become a global priority for sustainable development. Existing methods for assessing accessibility, particularly variants of the two-step floating catchment area (2SFCA) model, have made progress but remain limited in incorporating multimodal transport systems and the spatial morphology of green infrastructure. To address these gaps, this study proposes an integrated framework that combines an enhanced three-step floating catchment area (3SFCA) method with Morphological Spatial Pattern Analysis (MSPA). Using Fuzhou, China, as a case study, the framework evaluates equity in UGS accessibility across walking, cycling, public transit, and driving, and investigates how spatial morphology shapes service opportunities. Results reveal pronounced inequities, particularly under active travel modes, and demonstrate that morphological patterns significantly mediate equity outcomes. Notably, persistent severe low location entropy is concentrated in the urban core despite high green space density. The citywide Gini coefficient reaches 0.853, with modal-specific Gini coefficients ranging from 0.974 (walking) and 0.925 (cycling) to 0.736 (public transport) and 0.612 (driving). The study contributes methodologically by incorporating choice weights and multimodal travel times into 3SFCA and feeds MSPA-derived morphological variables into multiscale geographically weighted regression (MGWR)/Geodetector; and practically by offering planning insights transferable to rapidly urbanizing cities worldwide.