Spatiotemporal Characterization of the Urban Expansion Patterns in the Yangtze River Delta Region

Ziqi Yu,Shuai Shi,Long Li,Zhiqiang Wang,Ruiyang Liu,Ting Zhang,Longqian Chen,Lina Yuan,Jinyu Zang

doi:10.3390/rs13214484

Abstract

Characterizing urban expansion patterns is of great significance to planning and decision-making for urban agglomeration development. This study examined the urban expansion in the entire Yangtze River Delta Region (YRDR) with its land-use data of six years (1995, 2000, 2005, 2010, 2015, and 2018). On the basis of traditional methods, we comprehensively considered the four aspects of urban agglomeration: expansion speed, expansion difference, expansion direction, and landscape pattern, as well as the interconnection of and difference in the expansion process between each city. The spatiotemporal heterogeneity of urban expansion development in this region was investigated by using the speed and differentiation indices of urban expansion, gravity center migration, landscape indices, and spatial autocorrelations. The results show that: (1) over the 23 years, the expansion of built-up land in the Yangtze River Delta Region was significant, (2) the rapidly expanding cities were mainly located along the Yangtze River and coastal areas, while the slowly expanding cities were mainly located in the inland areas, (3) the expansion direction of each city varied and the gravity center of the urban agglomeration moved toward the southwest, and (4) the spatial structure of the region became more clustered, the shape of built-up land turned simpler, and fragmentation decreased. This study unravels the spatiotemporal change of urban expansion patterns in this large urban agglomeration, and more importantly, can serve as a guide for formulating urban agglomeration development plans.

Highlights

IntroductionAs the world population and economy continue to grow, urban agglomerations have become a new trend in global urbanization
Urban land use in the YRDRarea continued to experience rapid by urban expansion the the late 1990s
Using the land-use data of six periods, we summarized the spatiotemporal evolution patterns of built-up land with urban speed indices and the differentiation indices of urban expansion, gravity center migration, landscape indices, and spatial autocorrelations

Summary

Introduction

As the world population and economy continue to grow, urban agglomerations have become a new trend in global urbanization. Managing and quantifying the expansion of urban agglomerations is a major challenge in this century [1,2]. Urban agglomerations are usually characterized by different population sizes [3], economic structures [4], landscape patterns [5], and road network densities [6,7]. These, together with many other factors, often result in a series of severe social and environmental problems [8] and geohydrological risks [9], ranging from increased temperatures [10,11] to polluted air [12], polluted water [13], and flood risk [14]. Around 1899, the urban expansion of Bamenda

Methods

Discussion

Conclusion