Associations between urban form and urban multifunctionality: a comparative study

Abstract Cities are complex and dynamic systems that integrate social, ecological, and infrastructure domains. This study investigates and quantifies how urban forms are associated with multiple urban functions across these domains, and how these associations combine into positive or negative synergies and trade-offs through multifunctional assessment rather than single-function analyses. Using Hong Kong and Zurich as two contrasting case cities, we analyse five key urban functions, including heat mitigation, pluvial flood regulation, bird diversity, mortality-derived health outcome, and small business vitality. Results from multifunctional analysis reveal that, despite contrasting urban contexts, consistent form-function relationships across domains can be observed. Increased impervious surface coverage was consistently negatively associated with pluvial flood and heat mitigation, whereas proximity to water was positively associated with both functions and tentatively associated with the mortality-derived health outcome. Green space form is associated with urban functions in diverse ways that can involve trade-offs, for example, irregular green patches are associated with higher bird diversity but lower pluvial flood mitigation capacity. Although the findings are generally consistent across the two cities, the magnitude and spatial heterogeneity of these relationships differ and are related to city-specific characteristics. Overall, the findings demonstrate that urban form is simultaneously associated with multiple urban functions within and across ecological and human domains. The study advances the understanding of urban multifunctionality across five selected urban function proxies and establishes a comparative framework for assessing and balancing cross-domain relationships within a clearly defined and representative indicator set, providing an integrated perspective for sustainable urban development.