Crowding types in high-density tourist cities: Based on a physical and-perceived density clustering analysis

Driven by global urbanization and the rise of mass tourism, crowding in high-density tourist cities has become a significant concern in the academic community. However, existing studies often lack a systematic categorization of crowding types, resulting in insufficiently targeted governance strategies. In this study, a two‑dimensional framework of physical and perceived crowding is employed to construct a comprehensive indicator system comprising eight physical crowding indicators and six perceived crowding indicators. Furthermore, twenty‑eight high‑density urban areas worldwide are selected, and cluster analysis is applied to identify crowding types and examine the key influencing factors of each type. The results present four crowding types: closely spaced narrow alley, high building quantity, high‑rise low‑greenery, and high vehicle interference. Additionally, correlation analysis reveals the interaction mechanisms that exist among factors. Building coverage is positively correlated with road network density. Moreover, building spacing is positively correlated with both the building height and the building height‑to‑width ratio. Façade color is positively correlated with the road network density. Finally, the number of vehicles within an area is positively correlated with both the road width and site area. Conversely, building coverage is negatively correlated with the building spacing, depth‑to‑height ratio (D/H), and green space ratio. In addition, building spacing is negatively correlated with the number of buildings within an area, and façade color is negatively correlated with the green space ratio. This research enriches the evaluation indices considered in both the physical and perceived dimensions. The four identified types of crowded spaces derived from empirical analysis can provide a scientific basis for developing future differentiated planning strategies.