A Multifractal-Inspired Approach for Scale-Dependent Street-Level Green Visibility: An “X-Minute Greenery’’ Framework

Urban systems exhibit multifractal scaling behaviors arising from their hierarchical and heterogeneous spatial organization. Yet the Green View Index (GVI), a widely used indicator of street-level green visibility, is conventionally measured as a static value, overlooking how green exposure is reorganized across scales, which may bias greening evaluations and planning decisions. This study proposes an “X-minute Greenery” framework to examine GVI as a scale-dependent spatial process. Street view imagery and walking isochrone data from Hong Kong and Shenzhen, China, are integrated to measure GVI across 5, 10, 15, and 20 min walking ranges, while a multifractal-inspired approach is developed to characterize its scale-dependent variation structure. Empirical findings show that (1) GVI variation is not random but associated with urban governance and spatial morphology; (2) a staged pattern of variation is identified, with a GVI level around 0.2 marking an approximate shift in configurations of greening dynamics; (3) even under similar initial GVI conditions, areas can still follow divergent variation patterns across walking scales, exposing latent spatial inequalities aligned with institutional and morphological factors. By framing urban green visibility as a scale-aware complex-systems phenomenon, this study adapts multifractal reasoning to street-level greenery, challenges the “equal green, equal policies” assumption, and supports context-sensitive planning interventions.