Understanding the 3D spatial structure of a city is increasingly essential for addressing various environmental and management issues, surpassing the importance of traditional 2D analysis. However, existing studies neglect the diversity of building height and still lack a clear description of 3D urban structure. This article proposes a new framework to uncover the 3D urban structure. Firstly, kernel density is employed to reveal the hierarchical spatial structure of buildings and the contour tree method is improved to quantitatively measure the spatial diversity and complexity. Then, the 3D urban structure is abstracted by spatial interpolation after feature filtration. Finally, this framework is applied to the central area of Chengdu City, revealing that: (1) Spatial structures of buildings with different heights exhibit significant diversity, location preference, and complexity; and (2) A globally “depression” 3D urban structure with low center—high periphery is obviously identified. This framework provides an effective way to reveal the 3D urban structure in a more intuitive and clearer way from various disordered urban buildings, which can be transferable to other cities and further facilitate sustainable planning and development of cities.

中文翻译：

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一种新的建筑高度层次分析框架：更直观地理解3D城市结构

了解城市的 3D 空间结构对于解决各种环境和管理问题越来越重要，其重要性超过了传统的 2D 分析。然而，现有研究忽视了建筑高度的多样性，仍然缺乏对3D城市结构的清晰描述。本文提出了一个揭示 3D 城市结构的新框架。首先，利用核密度揭示建筑物的层次空间结构，并改进等值线树方法来定量衡量空间多样性和复杂性。然后，经过特征过滤后通过空间插值抽象出3D城市结构。最后，将该框架应用于成都市中心城区，结果表明：（1）不同高度建筑的空间结构表现出显着的多样性、区位偏好性和复杂性； （2）中心低外围高的全球“洼地”3D城市结构明显。该框架提供了一种有效的方法，从各种无序的城市建筑中以更直观、更清晰的方式揭示3D城市结构，可以移植到其他城市，进一步促进城市的可持续规划和发展。