Multi-Scale Spatial Representation and Function–Structure Joint Optimization in Ports and Adjacent Areas

Focusing on ports as important infrastructure units within complex urban systems, this study addresses the challenges of highly coupled multifunctional land use, complex spatial structures, and scale-sensitive modelling in port and port-adjacent areas by developing an integrated framework for multi-scale spatial representation and function–structure joint modelling. First, considering the relatively limited spatial extent of port areas and the high requirements for spatial information accuracy, land-use functional characteristics are described from the perspectives of composition, morphology, and spatial pattern. A two-level spatial scale selection model is proposed, in which landscape indices combined with mean change-point analysis are used to determine appropriate spatial representation scales for port land-use functions. On this basis, a joint optimisation model of land-use functions and spatial structure in port and port-adjacent areas is further developed. The model explicitly accounts for interactions among different land-use functions and spatial heterogeneity, and quantitatively optimises functional configurations and spatial structures by maximising a weighted objective of economic, ecological, and social benefits. Model validation based on case studies demonstrates that the proposed framework effectively captures the impacts of multifunctional coupling on overall system performance and reveals the pathways through which port subsystems influence urban spatial structure and environmental responses. The study provides a quantitative modelling approach to support the analysis and optimisation of key infrastructure subsystems within complex urban systems.