Key Definitions

Geographers define cities as nodes on circulation systems. That is, they are intersections in the pathways of communication and transportation. Cities exist to assemble, process, store and redistribute goods, people and ideas.

The size and wealth of city depends upon two general factors:

1. The size and wealth of its hinterland (or trade area, or support region).
2. The degree to which the city is connected to all the other cities in the world.

• The size of the hinterland and the degree of connectivity are both functions of circulation (transportation and communication) technology.
  
• At one time transportation and communication were essentially the same. Some physical object had to move for information to flow.
  
• The wealth of the hinterland is a function of many things, but the population's level of technology is the most important factor.

With these definitions in mind, it is possible to develop a view of cities that is based on innovations and diffusions of technology. This is what was done by the geography of John R. Borchert during the 1960s. Borchert developed a view of the urbanization of the United States that is based on epochs of technology. As the components of technology wax and wane, the urban landscape undergoes dramatic changes.

This graph shows four primary epochs between 1790 and 1960. The time series is based on the data in the Census of the United States, so it has an arbitrary beginning.

1. The first epoch is called the sail and wagon epoch because the predominant source of energy for shipping was wind power and wind power was used in a variety of mills. On land, the most efficient vehicle was the wagon. Wagons developed in Conestoga, Pennsylvania were among the most efficient in the world. This basic vehicle, which most Americans know as the "Covered Wagon," enabled farmers in the Lancaster area to shipping grain and other food stuffs to markets in Philadelphia and other growing seaboard cities. In many respects, this epoch extends back to antiquity. Travel on land was slow, so most urban places were ports on the sea coasts or interior water ways. Canals were built to improve access.
2. The second epoch, the steamboat - iron horse epoch, was the result of transferring machinery developed in the mining industry to both water and land transportation. The steam wagons were so heavy that special tracked roadways were built to support them and minimize friction. Steamboats made upstream travel efficient and profitable. During this period, the railroads were tributaries of ports. The graph shows the rapid increase of water travel and coal production. During this period, electricity freed communication from transportation.
3. The third epoch, the long haul or steel-rail epoch, dramatically improved land transportation and after a time nearly eliminated riverboat traffic. During this period, steam and electricity were applied to the manufacturing process which enabled factory owners to establish plants away from water power sites. As a result, many new manufacturing towns developed.
4. The fourth epoch, the automobile epoch, was/is very different. Now the dense network of roads makes it possible for cars and trucks to travel to just about every place in the country. This is described as "surface-like," a situation where movement is possible in any direction with equal ease. The advent of this epoch freed urbanization from the network of the railroad lines.

The key insight of Borchert's work is that it provides a lens for us to view the process of urbanization and enables us to make predictions about the future. Because urbanization is the result of innovations and their diffusion, we should be able to see the changes around us that will eventually shape the future of our cities. Thus, we should never be shocked by the future.