Coupling characteristics of coastal ports and urban network systems based on flow space theory: Empirical evidence from China

The port–city coupling system and spatial correlation are new perspectives in studying the port–city relationship. The flow space and the element network activate the economic location through the temporal and spatial compression effect, reshape the temporal and spatial relationship, and challenge the traditional port–city relationship. Based on the theory of ‘flow space’ and the ‘port–city relationship’, this study constructs two network systems of port and city. A theoretical framework and a measurement method for evaluating the coupling relationship between the port-city and the city from the perspective of flow space are proposed. Using Chinese coastal port cities as examples, this paper discusses the network characteristics and coupling patterns of port–city relations in the context of port regionalisation. The main findings are as follows. First, the port network system is subject to obvious geographical constraints and exhibits the network characteristics of ‘group development’ and ‘axis-spoke’ coexistence; the urban network system reduces to a certain extent the dependence on the space of port cities. It shapes the traditional geographical space and exhibits the network characteristics of ‘multi-core’. Second, types of port–city coupling are diverse, but the regional agglomeration characteristics are obvious. Compared to 2006, the distribution of coupling types in the whole network system of port cities in 2016 is relatively balanced, and the structure tends to be perfect. Finally, flow elements and port functions are the core elements that influence the coupling characteristics of port cities from the perspective of ‘flow space’. The flow element promotes an advanced community relationship between port cities. The port and the city realise the greatest value and the highest comprehensive efficiency. Due to the intergenerational differences of ports, the impact of port functions on the evolution of city functions is different, leading to some level differences in the development of port cities. •A coastal port network system for China's coastal cities is constructed.•Flow space theory underpins the study.•The regional port–city network coupling relationships are analysed.•The degree of network system development is assessed, using multiple flows.•Focus: The flow of cargo, people, capital, technology, and information.