sustainability Article Quantifying the Spatial Integration Patterns of Urban Agglomerations along an Inter-City Gradient Yiliang Wan 1,2,† , Chuxiong Deng 1,2,*,†, Tao Wu 1,2,*,†, Rui Jin 3,†, Pengfei Chen 4,5 and Rong Kou 4 1 College of Resources and Environment Sciences, Hunan Normal University, Changsha 410081, China;
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[email protected] (R.K.) 5 Department of Land Surveying and Geo-Informatics, The Hongkong Polytechnic University, Hongkong, China * Correspondence:
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[email protected] (T.W.); Tel.: +86-1357-416-9718 (C.D.); +86-1997-695-5055 (T.W.) † These authors contributed equally to this work. Received: 3 August 2019; Accepted: 9 September 2019; Published: 12 September 2019 Abstract: Understanding the integration process of urban agglomeration is essential for sustainable regional development and urban planning. However, few studies have analyzed the spatial integration patterns of metropolitan regions according to the impacts of landscape ecology along rail transit corridors. This study performed a comprehensive inter-city gradient analysis using landscape metrics and radar charts in order to determine the integration characteristics of an urban agglomeration. Specifically, we analyzed the evolution of spatial heterogeneity and functional landscapes along gradient transects in the Changsha–Zhuzhou–Xiangtan (CZT) metropolitan region during the period of 1995–2015.