Characterizing the spatial organization of urban functions using a distance-based colocation quotient approach: With special reference to Beijing

Abstract

The study of spatial layout patterns of urban functions is crucial for enhancing urban vitality and addressing spatial inefficiencies. Although existing research has developed methods for accurately identifying urban functional areas, the crucial role of functional interdependencies, expressed through colocation, in shaping complex urban structures remains inadequately explored. To address this gap, this study proposes a methodological framework for calculating distance-based co-location quotients (DBCLQ) and constructing a colocation network to extract functional clusters. Empirical analysis in Beijing identifies typical colocation pairs and the distance intervals at which these relationships manifest. Asymmetric colocation relationships are observed, indicating that educational facilities, transportation services, and scenic facilities demonstrate a strong attraction to most nearby functions. The study also challenges universal applicability of distance decay in colocation analysis, showing that some colocation relationships are scale-specific, emerging only within particular distance thresholds. The colocation network of Beijing's functions reveals a complex, multi-layered urban functional fabric composed of interconnected and overlapping clusters. By classifying their morphology, clusters are categorized into four organizational patterns: central radial, linear, extensive area-wide, and dense nodal pattern, summarizing the common function types associated with different organizational patterns.