While the spatial and functional relationships between ports and cities have been put in question in the last decades, the continued importance of urbanization and maritime transport in global socio-economic development motivates deeper research on their interaction. The global trade network is often studied at the country level and all transport modes included, concluding that distance remains a strong counterforce to exchange. This article wishes to detect whether the global container shipping network obeys similar properties at the city level. More than 2 million inter-port vessel movements between 1977 and 2016 are assigned to about 9000 ports and 4600 cities to run a gravity model on two different network topologies. Gravitational properties are found, as larger cities connect more with each other but less at distance. The degree of distance effects negatively expanded in 40 years, confirming the “puzzling” or reinforcing effect of distance, yet it varies greatly depending on node aggregation and network topology. We conclude that ports and cities continue to share important interdependencies, but these often rest on a detrimental physical transformation. A discussion is proposed about the underlying operational and theoretical mechanisms at stake. Keywords container shipping; gravity model; maritime trade; port cities; spatial interaction; world city networks.

中文翻译：

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全球集装箱航运网络中的城市重力

虽然港口和城市之间的空间和功能关系在过去几十年里一直受到质疑，但城市化和海上运输在全球社会经济发展中的持续重要性促使人们对其相互作用进行更深入的研究。全球贸易网络通常在国家层面进行研究，包括所有运输方式，得出的结论是距离仍然是交换的强大反作用力。本文希望检测全球集装箱航运网络是否遵循城市层面的类似属性。1977 年至 2016 年间，超过 200 万次港口间船舶运动被分配到约 9000 个港口和 4600 个城市，以在两种不同的网络拓扑结构上运行重力模型。引力特性被发现，因为大城市之间的联系更多，但距离更少。距离效应的程度在 40 年中呈负向扩大，证实了距离的“令人困惑”或强化效应，但它因节点聚合和网络拓扑的不同而有很大差异。我们得出结论，港口和城市继续共享重要的相互依存关系，但这些往往依赖于有害的物理转变。建议讨论潜在的操作和理论机制。关键词 集装箱运输；重力模型；海上贸易；港口城市；空间互动；世界城市网络。但这些往往依赖于有害的物理转变。建议讨论潜在的操作和理论机制。关键词 集装箱运输；重力模型；海上贸易；港口城市；空间互动；世界城市网络。但这些往往依赖于有害的物理转变。建议讨论潜在的操作和理论机制。关键词 集装箱运输；重力模型；海上贸易；港口城市；空间互动；世界城市网络。