Zhang Xiaohui, Zhang Jifei
Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, 610299, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Heliyon. 2023 Oct 13;9(10):e20949. doi: 10.1016/j.heliyon.2023.e20949. eCollection 2023 Oct.
The Chengdu-Chongqing urban agglomeration (CCUA), as the only national-level city cluster in southwestern China, serves as a strategic support for the Yangtze River Economic Belt and an important demonstration area for promoting new urbanization in the country. The study of the networked characteristics of the CCUA contributes to a systematic understanding of its spatial connectivity patterns, optimization of spatial structure and layout, and promotion of high-quality regional development. In this study, we constructed models for traffic flow, information flow, migration flow, and composite flow to calculate the strength of connections between cities and the total flow of various elements in the CCUA. ArcGIS spatial visualization tools were used to depict the spatial connectivity patterns of the element flows within the CCUA. Additionally, social network analysis methods, including network density, centrality, and cohesive subgroups analysis, were employed to reveal the spatial network structure characteristics of the CCUA. The findings are as follows: (1) The overall structure of the cities within the CCUA is relatively loose, with significant differences in connectivity strength. It exhibits a west-strong and east-weak pattern, with Chengdu-Chongqing, Chengdu-Deyang, Chengdu-Mianyang, and Chengdu-Meishan occupying the top tier, while Zigong and Ya'an have relatively weak connections with other cities. Chengdu and Chongqing have prominent positions in the CCUA, with Chengdu having a more prominent core position compared to Chongqing, resulting in an overall hierarchical distribution of "1 + 1+7 + 7". (2) The network density of the element flows in the CCUA is relatively low, indicating a generally weak element connectivity. The centrality of cities other than Chengdu and Chongqing is at a moderate to lower level, suggesting a weak overall resource connectivity capacity in the CCUA. (3) Most cities tend to form cohesive subgroups based on geographic proximity, while the cohesive subgroup in Chongqing is still in its early stages of development due to administrative boundaries. The research results quantitatively depict the spatial network structure characteristics of the CCUA, providing theoretical references for its development.
成渝城市群作为中国西南地区唯一的国家级城市群，是长江经济带的战略支撑和国家推进新型城镇化的重要示范区。对成渝城市群网络特征的研究有助于系统了解其空间连接模式、优化空间结构与布局以及推动区域高质量发展。在本研究中，我们构建了交通流、信息流、迁移流和复合流模型，以计算成渝城市群内城市间的连接强度和各类要素的总流量。利用ArcGIS空间可视化工具描绘成渝城市群内要素流的空间连接模式。此外，采用包括网络密度、中心性和凝聚子群分析在内的社会网络分析方法，揭示成渝城市群的空间网络结构特征。研究结果如下：（1）成渝城市群内城市的整体结构较为松散，连接强度差异显著。呈现西强东弱的格局，成渝、成德、成绵、成眉处于第一梯队，而自贡和雅安与其他城市的连接相对较弱。成都和重庆在成渝城市群中地位突出，其中成都的核心地位比重庆更为显著，形成了 “1 + 1 + 7 + 7” 的总体层级分布。（2）成渝城市群要素流的网络密度相对较低，表明要素连接总体较弱。除成都和重庆外，其他城市的中心性处于中等偏下水平，说明成渝城市群整体资源连接能力较弱。（3）多数城市倾向于基于地理邻近性形成凝聚子群，但重庆的凝聚子群由于行政边界仍处于发展初期。研究结果定量描绘了成渝城市群的空间网络结构特征,为其发展提供了理论参考。
