The port city provides a fascinating and rich understanding of the movement of people and goods around the world. We understand a port as a centre of land-sea exchange, and as a major source of livelihood and a major force for cultural mixing. But do ports all produce a range of common urban characteristics which justify classifying port cities together under a single generic label? Do they have enough in common to warrant distinguishing them from other kinds of cities?
A A port must be distinguished from a harbor. They are two very different things. Most ports have poor harbors, and many fine harbors see few ships. Harbor is a physical concept, a shelter for ships; port is an economic concept, a centre of land-sea exchange which requires good access to a hinterland even more than a sea-linked foreland. It is landward access, which is productive of goods for export and which demands imports, that is critical. Poor harbors can be improved with breakwaters and dredging if there is a demand for a port.
B Port cities become industrial, financial and service centers and political capitals because of their water connections and the urban concentration which arises there and later draws to it railways, highways and air routes. Water transport means cheap access, the chief basis of all port cities. Many of the world's biggest cities, for example,
C Port functions, more than anything else, make a city cosmopolitan. A port city is open to the world. In it races, cultures, and ideas, as well as goods from a variety of places, jostle, mix and enrich each other and the life of the city. The smell of the sea and the harbor, the sound of boat whistles or the moving tides are symbols of their multiple links with a wide world, samples of which are present in microcosm within their own urban areas.
D Sea ports have been transformed by the advent of powered vessels, whose size and draught have increased. Many formerly important ports have become economically and physically less accessible as a result. By passed by most of their former enriching flow of exchange, they have become cultural and economic backwaters or have acquired the character of museums of the past. Examples of these are
E Much domestic port trade has not been recorded. What evidence we have sug3ests that domestic trade was greater at all periods than external trade.
F No city can be simply a port but must be involved in a variety of other activities. The port function of the city draws to it raw materials and distributes them in many other forms. Ports take advantage of the need for breaking up the bulk material where water and land transport meet and where loading and unloading costs can be minimized by refining raw materials or turning them into finished goods. The major examples here are oil refining and ore refining, which are commonly located at ports. It is not easy to draw a line around what is and is not a port function. All ports handle, unload, sort, alter, process, repack, and reship most of what they receive. A city may still be regarded as a port city when it becomes involved in a great range of functions not immediately involved with ships or docks.