Department of Civil and Environmental Engineering, Swiss Federal Institute of Technology Lausanne, Lausanne, VD, Switzerland.
School of Arts, Sciences and Humanities, University of Sao Paulo, Sao Paulo, SP, Brazil.
PLoS One. 2018 Oct 4;13(10):e0204574. doi: 10.1371/journal.pone.0204574. eCollection 2018.
During the last years, the new science of cities has been established as a fertile quantitative approach to systematically understand the urban phenomena. One of its main pillars is the proposition that urban systems display universal scaling behavior regarding socioeconomic, infrastructural and individual basic services variables. This paper discusses the extension of the universality proposition by testing it against a broad range of urban metrics in a developing country urban system. We present an exploration of the scaling exponents for over 60 variables for the Brazilian urban system. Estimating those exponents is challenging from the technical point of view because the Brazilian municipalities' definition follows local political criteria and does not regard characteristics of the landscape, density, and basic utilities. As Brazilian municipalities can deviate significantly from urban settlements, urban-like municipalities were selected based on a systematic density cut-off procedure and the scaling exponents were estimated for this new subset of municipalities. To validate our findings we compared the results for overlaying variables with other studies based on alternative methods. It was found that the analyzed socioeconomic variables follow a superlinear scaling relationship with the population size, and most of the infrastructure and individual basic services variables follow expected sublinear and linear scaling, respectively. However, some infrastructural and individual basic services variables deviated from their expected regimes, challenging the universality hypothesis of urban scaling. We propose that these deviations are a product of top-down decisions/policies. Our analysis spreads over a time-range of 10 years, what is not enough to draw conclusive observations, nevertheless we found hints that the scaling exponent of these variables are evolving towards the expected scaling regime, indicating that the deviations might be temporally constrained and that the urban systems might eventually reach the expected scaling regime.
在过去的几年中，城市新科学已经确立为一种系统地理解城市现象的富有成效的定量方法。其主要支柱之一是城市系统在社会经济、基础设施和个人基本服务变量方面表现出普遍的规模规律。本文通过在发展中国家城市系统中对广泛的城市指标进行测试，讨论了普遍性命题的扩展。我们提出了对巴西城市系统的 60 多个变量的缩放指数进行探索。从技术角度来看，估计这些指数具有挑战性，因为巴西市政当局的定义遵循地方政治标准，而不考虑景观、密度和基本公用事业的特征。由于巴西市政当局可能与城市定居点有很大差异，因此根据系统密度截止程序选择了类似城市的市政当局，并为这个新的市政当局子集估计了缩放指数。为了验证我们的发现，我们将叠加变量的结果与基于替代方法的其他研究进行了比较。结果发现，分析的社会经济变量与人口规模呈超线性关系，大多数基础设施和个人基本服务变量分别呈预期的次线性和线性关系。然而，一些基础设施和个人基本服务变量偏离了预期的范围，对城市规模的普遍性假设提出了挑战。我们提出，这些偏差是自上而下的决策/政策的产物。我们的分析跨越了 10 年的时间范围，这不足以得出结论性的观察结果，但我们发现了一些迹象表明这些变量的缩放指数正在向预期的缩放范围发展，这表明偏差可能是暂时的，城市系统最终可能会达到预期的缩放范围。
