Evolving spatial structure of metropolitan areas at a global scale: a context-sensitive review

Abstract

The increased population and the fast expansion of urbanization were some of the global main characteristics in the past decades. This expansion has shaped the diverse spatial structure in metropolitan areas worldwide. However, these studies have been focused on one or some metropolitan areas within countries or continents and no systematic review, to the best of our knowledge, has ever addressed the spatial structure of metropolitan areas and their contextual factors at a global scale. Thus, this paper attempts to address this gap through a deeper understanding of the evolving spatial structure of metropolitan areas at a global scale and studying the driving and contextual factors affecting them. To this end, the authors examined the empirical evidence conducted in this field using a systematic review method. The statistical society of this article consists of English-based scientific articles published in peer-reviewed journals between 1980 and 2020, which were obtained through a search in scientific databases using the related keywords to the spatial structure of metropolitan areas. After searching for relevant articles and based on the relationship between titles, keywords, and content, 161 articles were selected and carefully examined. The results show that the spatial structure of the metropolitan areas during the last forty years can be categorized into four macro divergent, convergent, homogenous, and heterogeneous patterns. These patterns were not absolute but subject to the centripetal and centrifugal forces experienced different growth trends, leading to various spatial structures.