THE GEOGRAPHY OF TRANSPORT SYSTEMS
There is potentially an infinite number of maritime shipping routes but the configuration of the global system is relatively simple. The main axis is a circum-equatorial corridor linking North America, Europe and Pacific Asia through the Suez Canal, the Strait of Malacca and the Panama Canal.
Maritime routes are a function of obligatory points of passage, which are strategic places, of physical constraints (coasts, winds, marine currents, depth, reefs, ice) and of political borders. As a result, maritime routes draw arcs on the earth water surface as intercontinental maritime transportation tries to follow the great circle distance. The above map provides a simple taxonomy of the main strategic passages.