Effects of distance on the network topology of the global container shipping network

Like many communication systems, maritime networks are embedded in space. But the effects of spatial properties on the network itself have not been deeply examined in previous research. Gravitational properties affect international trade, as well as container shipping flows in general, as distance represents spatial friction to exchange; yet the ability of the network and of specific nodes and links to operating at different geographic ranges of connectivity remains unknown.

The latest port study of PortEconomic member Cesar Ducruet along with Dimitrios Tsiotas (Agricultural University of Athens, Greece) examines how spatial distance affects network topology on empirical data concerning the Global Container Shipping Network (GCSN). The GCSN decomposes into 32 multiplex layers, defined at several spatial levels, by successively removing connections of smaller distances. This multilayer decomposition approach allows studying the topological properties of each layer as a function of distance. The analysis provides insights into the hierarchical structure and (importing and exporting) trade functionality of the GCSN, hub connectivity, several topological aspects, and the distinct role of China in the network’s structure. It also shows that bidirectional links decrease with distance, highlighting the importance of asymmetric functionality in carriers’ operations.

This makes container shipping networks specific compared with airlines or international trade where most links are bidirectional. Based on a factor analysis confirming the correlation between traffic size and interaction range, it further configures six novel clusters of ports concerning their spatial coverage. In particular, the class of ‘transcalar ports’ stands out by its ability to ensure a comparable amount of traffic at all distances, from the shortest to the longest. Finally, it reveals three levels of geographical scale in the structure of GCSN (where the network topology significantly changes): the neighborhood (local connectivity); the scale of international connectivity (mesoscale or middle connectivity); and the intercontinental market (large scale connectivity).

The overall approach provides a methodological framework for analyzing network topology as a function of distance, highlights the spatial dimension in complex and multilayer networks, and provides insights into the spatial structure of the GCSN, which is the most important market of the global maritime economy.

Link to the (open access) article:Measuring the effect of distance on the network topology of the Global Container Shipping Network