基于加权Voronoi图的城市腹地界定方法研究——以成渝经济圈为例

Definition of Urban Hinterlands of Chengdu-Chongqing Economic Circle Based on Weighted Voronoi Diagram

中心城市腹地合理地划分对区域的资源整合、协调发展起到关键性的作用。本文立足于加权Voronoi图，将城市的中心性强度及综合交通可达性作为权重引入断裂点模型中，修正了断裂点模型中的城市人口规模，构建了加权Voronoi图城市腹地界定新模型；并以成渝经济圈36个中心城市为例，对模型进行验证。研究表明，成渝经济网各中心城市腹地与行政区范围吻合度较差。根据腹地与行政区范围大小的比值将城市划分为3类：比值大于100％的城市具有良好的适合腹地向外扩展的条件，对周边城市的发展有较大影响；比值在60％～100％之间的城市对周边城市的发展起到一定作用；比值小于60％的城市则说明周边城市的影响力远远大于本市。而四川省的成都市和重庆市的主城作为区域实力最强的城市，其腹地范围并不是最大的，这表明城市腹地的范围及大小主要由中心城市的综合实力和周边城市的综合实力共同决定。这是对成渝经济圈各城市腹地的重新界定，对成渝经济圈城市规划有一定参考意义。

Among the influencing factors of regional resources integration and coordinated development, a rea- sonable division of city hinterland plays a key role. Based on the weighted Voronoi diagram, we put urban cen- tricity intensity and comprehensive transportation accessibility as the weights into the breaking point model, and then revised the urban population scale in the model. As such we constructed a new urban hinterland definition model based on the weighted Voronoi model. To verify this new model, we took 36 central cities in Cheng- du-Chongqing Economic Circle as an example to do a test. The result shows that, in our test area, the hinterland extent of each city does not match the administrative region extent well. To make it clearer, we divided these cit- ies into three categories according to the ratio of the hinterland size and the administrative region size of each city. Cities, whose ratio is greater than 100%, have good conditions of hinterland outward extending and have great influence on the development of the surrounding cities. When the ratio is smaller than 60%, it indicates that the influence of the surrounding cities is much stronger than that of the central city itself. Once the ratio is be- tween 60% and 100%, the central cities make little sense to the development of the surrounding cities. Further- more, Chengdu City of Sichuan Province and Chongqing Municipality are both well-known as the most power- ful cities in this region, however, their hinterland extents are not the biggest of all the hinterlands in the region. This phenomenon shows that the extent and size of a city hinterland is not completely positively related to its comprehensive strength, and it should be defined by the comprehensive strength of both the central city and the surrounding cities. Finally, this article completes a redefinition of city hinterland for each city in Cheng- du-Chongqing Economic Circle, and it is expected to afford a certain reference to the future urban construction and city planning.