Evolution of the Spatial Structure of a City

The urban spatial structure basically considers the location of different activities as well as their relationships. Core activities are those of the highest order in the urban spatial structure, namely tertiary and quaternary activities involved in management (finance and insurance) and consumption (retailing). Central activities are concerned by production and distribution with activities such as warehousing, manufacturing, wholesaling and transportation. Peripheral activities are dominantly residential or servicing local needs. A central area refers to an agglomeration of core and/or central activities within a specific location. The emergence of a CBD (Central Business District; the central area of a city) is the result of an historical process, often occurring over several centuries (depending on the age of a city), that has changed the urban form and the location of economic activities. Obviously, each city has its own history, but it is possible to establish a general common process:

• (A) Pre industrial era. For cities that existed before the industrial revolution, the CBD was limited to small section of the city generally nearby the waterfront, the market and/or a site of religious or political importance. These were locations where major transactions took place and thus required financial, insurance, warehousing and wholesale services.
• (B) Industrial revolution. With the industrial revolution came mass production and mass consumption. This permitted the emergence of a distinct retailing and wholesaling part of the CBD while manufacturing located outside the core. Managing these expanding activities also created an increasing need for office space that located nearby traditional places of financial interaction. As the industrial revolution matured, major transportation axis spurred from the central area towards the periphery.
• (C) Contemporary era. After the Second World War, industries massively relocated away from central areas to suburban areas, leaving room to the expansion of administrative and financial activities. The CBD was thus the object of an important accumulation of financial and administrative activities, particularly in the largest cities as several corporations became multinational enterprises. These activities were even more willing to pay higher rents than retailing, thereby pushing some retail activities out of the CBD. New retailing sub-centers emerged in suburban areas because of road accessibility and because of the needs to service these new areas. Warehousing and transportation, no longer core area activities, have also relocated to new peripheral locations. The spatial structure of many cities became increasingly multi-nodal.