Revealing urban greenspace accessibility inequity using the carrying capacity-based 3SFCA method and location big data

Equitable access to greenspace is increasingly essential for sustainable cities worldwide. However, the traditional 2SFCA (Two-Step Floating Catchment Area) method ignores the match between recreation visits and carrying capacity and thus fails to detect the greenspace accessibility inequality. We measured the greenspace capacity based on location big data and further proposed a 3SFCA-based measurement method for the accessibility inequality of greenspaces. The results demonstrated that (1) the carrying capacity (carrying area and greenspace type) is the main driving factor for greenspace accessibility; (2) the spatial inequality (Gini coefficient=0.67) in the greenspace accessibility existed at three scales (community > subdistrict > district); (3) the high demand for comprehensive parks by residents leads to general inequalities in greenspace access, while the low supply of community parks causes unequal access to greenspaces for disadvantaged groups; (4) 2SFCA overestimated 85% of the greenspace recreation carrying area, leading to a significant overestimation of the community park accessibility and disadvantaged groups' accessibility to greenspaces; (5) the 3SFCA revealed that the visitor number (2,993 p) exceeded the carrying capacity (2,987 p) of greenspaces, and community parks faces interference from recreational usage. These findings help to plan more equitable greenspaces and promote sustainable development in cities and society.