Title: Settlement scaling law reveals population-land tensions in 7000+African urban agglomerations

Author(s): Xu, G (Xu, Gang); Zhu, MY (Zhu, Mengyan); Chen, B (Chen, Bin); Salem, M (Salem, Muhammad); Xu, ZB (Xu, Zhibang); Li, XC (Li, Xuecao); Jiao, LM (Jiao, Limin); Gong, P (Gong, Peng)

Source: HABITAT INTERNATIONAL  Volume: 142  Article Number: 102954  DOI: 10.1016/j.habitatint.2023.102954  Published: DEC 2023  

Abstract: Allometric urban scaling law quantifies disproportional relationships between urban indicators and city size, which has been reported across developed countries and parts of the global south, but its applicability in Africa is neglected. Here, taking built-up areas derived from remote sensing in more than 7000 African agglomerations in 2015 as examples, we systematically investigate this settlement scaling law from continental, regional, and country levels. Results show that the built-up area linearly scales with population across the African continent and within northern and western Africa, while it sub-linearly scales with population in southern (beta = 0.85, 95% CI: 0.808-0.891) and central (beta = 0.93, 95% CI: 0.906-0.957) Africa, but super-linearly (beta = 1.10, 95% CI:1.068-1.121) in eastern Africa. National settlement scaling exponents (beta) vary from 0.65 to 1.25 with an average of 0.96, whose 63.6% variance can be explained by their share of built-up area, share of metropolitan population, GDP per capita, and proportion of slum dwellers. Residuals of scaling fitting reflect local populationland tensions. Western and eastern Africa are relatively rich in buildable land resources, while northern Africa is relatively poor. This study expanded the settlement scaling theory in Africa and multiple indicators are needed to further understand the rapidly evolving African urban systems.

Author Keywords: Urban scaling; Urban settlement; Complex urban system; Population-land relationship; Africa

Addresses: [Xu, Gang; Zhu, Mengyan; Jiao, Limin] Wuhan Univ, Sch Resource & Environm Sci, Wuhan 430079, Peoples R China.

[Xu, Gang; Chen, Bin] Univ Hong Kong, Fac Architecture, Div Landscape Architecture, Future Urban & Sustainable Environm FUSE Lab, Hong Kong 999077, Peoples R China.

[Xu, Gang; Chen, Bin; Gong, Peng] Univ Hong Kong, Urban Syst Inst, Hong Kong 999077, Peoples R China.

[Salem, Muhammad] Cairo Univ, Fac Urban & Reg Planning, Giza 12613, Egypt.

[Xu, Zhibang] Chinese Acad Sci, Inst Urban Environm, Xiamen 361021, Peoples R China.

[Li, Xuecao] China Agr Univ, Coll Land Sci & Technol, Beijing 100083, Peoples R China.

[Gong, Peng] Univ Hong Kong, Dept Geog, Hong Kong 9990777, Peoples R China.

[Gong, Peng] Univ Hong Kong, Dept Earth Sci, Hong Kong 9990777, Peoples R China.

Corresponding Address: Xu, G (corresponding author), Wuhan Univ, Sch Resource & Environm Sci, Wuhan 430079, Peoples R China.

Xu, ZB (corresponding author), Chinese Acad Sci, Inst Urban Environm, Xiamen 361021, Peoples R China.

郵箱地址：xugang@whu.edu.cn; zhumengyan@whu.edu.cn; binley.chen@hku.hk; m.salem@cu.edu.eg; zbxu@iue.ac.cn; xuecaoli@cau.edu.cn; lmjiao@whu.edu.cn; penggong@hku.hk

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