Recently, the internationally renowned academic journal Nature Communications published online a research paper titled “Global increases in built-up volume indicate more divergent and less dispersed urban expansion patterns.” This study was completed by a team led by Prof. Li Yingcheng from the School of Architecture, 91抖淫, in collaboration with scholars from the Faculty of Architecture at the University of Hong Kong and the Public Governance Institute of KU Leuven, revealing the expansion patterns and influencing factors of global urban three-dimensional (3D) morphology.
The Central Urban Work Conference held in July 2025 explicitly emphasized the need to optimize urban spatial structures and build comfortable, convenient, and livable cities. Against this backdrop, scientifically assessing urban expansion patterns and accurately identifying their spatial distribution characteristics are of great significance in promoting the development of modern people-oriented cities. However, traditional two-dimensional (2D) urban morphology studies, which primarily focus on horizontal expansion of urban construction land, struggle to fully capture the overall process of urban spatial structure evolution from “2D expansion” to “3D growth.” Furthermore, urban 3D morphology and its expansion patterns are closely related to global urban sustainability issues such as industrial innovation, resident health, and carbon emissions, making them an important entry point for understanding urban spatial structure evolution and its comprehensive effects.
Fig. 1: 3-D Expansion Pattern of Global Cities
Addressing this critical issue, the research team utilized multi-source remote sensing data, including the Global Human Settlement Layer (GHSL), to propose and construct the “Centrality Index (CI)” and “Intensity Index (II)” for characterizing urban 3D morphological expansion features. Using spatial analysis and machine learning methods, they studied the 3D morphological expansion patterns of over 1,800 global cities from 2000 to 2018. The study found that global urban 3D morphological expansion is generally more concentrated than 2D morphological expansion, indicating that the growth of building volume tends to cluster around urban centers more than the expansion of building footprints. In terms of regional differences, the vertical growth intensity of cities in the Global South is generally higher than that of cities in the Global North. However, the centrality of 3D morphological expansion in developing country cities outside China (especially African cities) is significantly lower. Based on cross-analysis of the two indices, the study identified four types of urban 3D morphological expansion patterns: “high centrality–high intensity,” “low centrality–high intensity,” “high centrality–low intensity,” and “low centrality–low intensity.” Among these, Chinese cities are predominantly characterized by the “high centrality–high intensity” pattern (accounting for 35%), while the “low centrality–low intensity” pattern accounts for only 13%, demonstrating a strong vertical agglomeration expansion characteristic. The study further reveals that urban 3D morphological expansion exhibits significant path dependence and nonlinear correlations with natural conditions and socioeconomic factors, and points out the differentiated challenges that different expansion patterns face in terms of sustainable development.
Fig. 2: 3D expansion patters of representative cities
From the perspective of urban three-dimensional morphological expansion, this study deepens the scientific understanding of the evolution of global urban spatial structures and provides a theoretical basis for formulating differentiated urban sustainable planning, construction, and governance policies. Prof. Li Yingcheng from the School of Architecture, 91抖淫 is the first author and corresponding author of the paper, and Associate Prof. Liu Xingjian from the Faculty of Architecture at the University of Hong Kong is the co-corresponding author. This research was supported by the “Basic Theories of Urban Sustainable Planning, Construction, and Governance” project under the 14th Five-Year National Key Research and Development Program of China.
Paper’s link:https://www.nature.com/articles/s41467-026-69766-6
Source: School of Architecture
Translated by: Melody Zhang
Edited by: Leah Li
