International Journal of Geo-Information Article Detecting and Analyzing Urban Centers Based on the Localized Contour Tree Method Using Taxi Trajectory Data: A Case Study of Shanghai Mengqi Sun 1 and Hongchao Fan 2,* 1 School of Remote Sensing and Information Engineering, Wuhan University, Wuhan 430079, China;
[email protected] 2 Department of Civil and Transport Engineering, Norwegian University of Science and Technology, 7491 Trondheim, Norway * Correspondence:
[email protected] Abstract: Urban structure is of vital importance to urban planning, transportation, economics and other applications. Since detecting and analyzing urban centers is crucial for understanding urban structure, a large number of studies on urban center extraction have been performed. In this paper, we propose an analysis framework to identify urban centers by using taxi trajectory data. The proposed approach differs from previous methods by employing a novel way to simulate taxi trajectory data with the topographic surface. We extracted pick-up and drop-off spots from taxi trajectory data and employed the localized contour tree method to delineate the boundaries and hierarchies of urban centers. The experiments show that the proposed method can successfully detect urban centers and analyze their temporal patterns in different periods in Shanghai, China. Citation: Sun, M.; Fan, H. Detecting and Analyzing Urban Centers Based Keywords: urban structure; urban center; taxi trajectory data on the Localized Contour Tree Method Using Taxi Trajectory Data: A Case Study of Shanghai. ISPRS Int. J. Geo-Inf. 2021, 10, 220. 1. Introduction https://doi.org/10.3390/ ijgi10040220 Urban structure is defined as the spatial arrangement of different land uses in urban areas [1].