<10 20 50 100 200 500 1000 2000 >5000 journeys 0 1 2 3 > 4 betweenness / 10 4 The 20 most central ports 1 Panama Canal 2 Suez Canal 3 Shanghai 4 Singapore 5 Antwerp 6 Piraeus 7 Terneuzen 8 Plaquemines 9 Houston 10 Ijmuiden 11 Santos 12 Tianjin 13 New York & New Jersey 14 Europoort 15 Hamburg 16 Le Havre 17 St Petersburg 18 Bremerhaven 19 Las Palmas 20 Barcelona a b FIG. 1: Routes, ports and betwe enness centralities in the global cargo ship network (GCSN). (a) The trajectories of all cargo ship s bigger than 10 , 000 GT during 2007. The color scale indicates the number of journeys along eac h route. Ships are assumed to travel along the shortest (geodesic) paths on water. (b) A map of th e 50 ports of highest betweenness centrality and a ranked list of the 20 most central ports. 18 The global cargo ship network