Exploring Allometric Scaling Relations between Fractal Dimensions of Metro Networks and Economic, Environmental and Social Indicators: A Case Study of 26 Cities in China

Tian Lan,Qian Peng,Jing Li,Haoyu Wang,Xinyu Gong,Zhicheng Shi

doi:10.3390/ijgi10070429

Abstract

Allometric scaling originates in biology, where it refers to scaling relations between the size of a body part and the size of the whole body when an organism grows. In cities, various allometric relations have also been discovered, such as those between the complexity of traffic networks and urban quantities. Metro networks are typical traffic networks in cities. However, whether allometric relations with metro networks exist is still uncertain. In this study, “fractal dimension” was employed as the complexity measure of metro networks, and potential allometric relations between fractal dimensions and urban indicators in 26 main cities in China were explored. It was found that fractal dimensions of metro networks had positive allometric relations with gross domestic product (GDP), population, particulate matter with a diameter less than 2.5 microns (PM2.5), the road congestion index and the average price of second-hand housing (with Spearman’s R of 0.789, 0.806, 0.273, 0.625 and 0.335, respectively) but inverse allometric relations with sulfur dioxide (SO2) and residential satisfaction (with Spearman’s R of −0.270 and −0.419, respectively). Such discoveries imply that allometric relations do exist with metro networks, which is helpful in deepening our understanding of how metro systems interact with urban quantities in the self-organized evolution of cities.

Highlights

IntroductionAllometry ( called allometric growth or allometric scaling) is a concept that originally referred to scaling relations between the size of a body part and the size of the whole body when an organism grows [1,2]
Allometry is a concept that originally referred to scaling relations between the size of a body part and the size of the whole body when an organism grows [1,2]
In terms of the p-value, it was found that seven dependent variables (GDP, population, PM2.5, SO2, road traffic congestion index, average price of second-hand housing and average residential satisfaction score) had strong allometric relations with fractal dimensions of metro networks with p-values smaller than 0.2, while five other dependent variables had p-values larger than 0.2

Summary

Introduction

Allometry ( called allometric growth or allometric scaling) is a concept that originally referred to scaling relations between the size of a body part and the size of the whole body when an organism grows [1,2]. The literature on urban allometry presents three primary themes: (1) exploration of potential allometric relations in cities, such as those between urban size and socio-economic quantities [12,13,14,15,16,17,18,19,20,21,22,23,24]; (2) development of novel metrics, rules or methods for better analysis of potential allometric relations [25,26,27,28,29,30]; and (3) explanations of the existence of urban allometric relations and analysis of how such relations affect socio-economic status [31,32,33,34] All these studies are helpful for people to better understand, design and plan sustainable cities and, nowadays, allometric analysis has become an important tool for analyzing scale-free processes and patterns in geographical systems [35,36]

Results

Discussion

Conclusion