ABSTRACT
A point zero represents a central geographical location of a city, which is essential for not only measuring distances, but also understanding the historical and/or cultural origin of a city. Although extensive studies have focused on delineating city centers, to our knowledge, no studies have paid attention to determining the location for a point zero. Here, our goal is to investigate various potential approaches for identifying such a location. Specifically, three typical approaches, geometric-based, topological-based, and thematic-based, are proposed to recommend point zeros and different scales, administrative divisions, kernel density surfaces, and regions enclosed by ring roads are used for analysis. The effectiveness of different approaches and scales are evaluated and compared by calculating an offset distance between recommended and actual point zero locations in 20 Chinese cities. Using the different approaches, the average offset distance for most Chinese cities is 2–4 km, and the thematic-based approach performs best. Both the topological-based and thematic-based approaches are less sensitive to the analyzed scale than the geometric-based approach. The results indicate that it is possible to determine the approximate location for a point zero from geographical data. Based on the buffer zone of such a location, an actual point zero may further be recommended.
Acknowledgments
We wish to thank Mr. Saisai Zhao and Ms. Shijia Sun for their technical supports on data processing, and the anonymous reviewers whose comments have greatly improved this paper.
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Notes on contributors
Qi Zhou
Qi Zhou is an associate professor in School of Geography and Information Engineering, China University of Geosciences (Wuhan). He received his Ph.D. in the Department of Land Surveying and Geo-Informatics at Hong Kong Polytechnic University. His research interests include the assessment and use of VGI and open data in urban topics.
Mingjian Zhai
Mingjian Zhai is an undergraduate student in School of Geography and Information Engineering, China University of Geosciences (Wuhan).
Wenhao Yu
Wenhao Yu is an associate professor in School of Geography and Information Engineering, China University of Geosciences (Wuhan). His research interests include map generalization and data mining.