The analysis of port regionalization process: the Spanish ports' case

The analysis of the scope, boundaries and evolution of a port hinterland is not a very common topic on the ports literature. The rise experienced by the logistic activity has shifted the interest towards the maritime routes, leaving aside the studies dealing with the inland maritime traffic distribution. One of the reasons why this approach is commonly adopted might be the fact that the competition over the traffic is increasingly taking place among the logistic chains. Based on this idea, the development of the intermodal transportation would have caused a shift on the degree of dependency of the ports on their geographically closer area. However, there is not a general consensus on this hypotheses. Other authors defend that each port belongs to a system and their activity growth is closely link to their economic, social and political environment. These approaches, apparently contradicting, can be however be considered complementary given the double condition of the ports: centrality vs intermediacy. In this paper we first describe the spatial origin of the maritime traffic in Spain and how it is distributed among the main container ports. The aim is to analyse the port's ability to penetrate into the inland Spanish territory. With this objective in mind, we set the boundaries of the ports hinterland at high level of detail using municipal data and the location of the companies generating the trade flows. The port hinterland boundaries suggested can help us to identify the more suitable inland corridors to connect one port to the inland islands generating traffic. Then, we suggest a combined index that permits evaluating both the geographical dispersion of a port hinterland and the hinterland homogeneity in generating that traffic. The main advantage of this Diversification index lies in its simplicity to do a first diagnosis on the port's spatial dependency given both its own specific characteristics and also in comparison to the others. As the index is a combination of two other indexes with minimum and maximum values, another advantage is the ability to disintegrate the different -and at times apparently opposite-, factors affecting the total value of the Diversification index delta. We believe this combined index sets a solid base to continue working on the development of a comprehensive analysis tool.