Cities & Geography Historically, urban settlements were very small and compact. As these settlements have rapidly increased in size, however, definitions have been created to describe their different parts: the central city, the urban area, and the metropolitan area.
Central City A central city (or simply city) is an urban settlement that has been legally incorporated into an independent, self-governing unit known as a municipality. Virtually all countries have a local government system that recognizes cities as legal entities with defined boundaries.
Metropolitan Area The U.S. Bureau of the Census has created a method of measuring the larger functional area of a settlement, known as the metropolitan statistical area (MSA). An MSA includes an urbanized area with a population of at least 50,000, the county within which the city is located, and adjacent counties with a high population density and a large percentage of residents working in the central city’s county.
The census has also designated smaller urban areas as micropolitan statistical areas (μSAs). A μSA includes an urbanized area of between 10,000 and 50,000 inhabitants, the county in which it is located, and adjacent counties tied to the city. The census combines MSAs and μSAs in several ways. A core-based statistical area (CBSA) is any one MSA or μSA. A combined statistical area (CSA) is two or more contiguous CBSAs tied together by commuting patterns. A primary statistical area (PSA) is a CSA, an MSA not included in a CSA, or a μSA not included in a CSA.
Urban Area An urban area consists of a central city and its surrounding built-up suburbs. The U.S. census recognizes two types of urban areas. The urbanized area is an urban area with at least 50,000 inhabitants. An urban cluster is an urban area with between 2,500 and 50,000 inhabitants.
Overlapping Metropolitan Areas In the northeastern United States, large metropolitan areas are so close together that they now form one continuous urban complex, extending north of Boston to south of Washington, D.C., this region is known as megalopolis. Other continuous urban complexes exist in the United States—the southern Great Lakes between Chicago and Milwaukee on the west and Pittsburgh on the east, and southern California from Los Angeles to Tijuana.
The Central Business District The central business district (CBD) is the core of the city where many services cluster. Services are attracted to the CBD because of its accessibility. The CBD is usually near the original site of settlement. The CBDs of older cities are often situated along a body of water.
Public Services in CBDs Public services typically located in a CBD include city hall, courts, county and state agencies, and libraries. Public services are located in the CBD to facilitate access for people living in all parts of town. Sports facilities and convention centers are found in the CBD and attract many suburbanites and out-of-towners. Cities place these facilities in the CBD because they hope to stimulate business for downtown restaurants, bars, and hotels.
Consumer Services in CBDs Retail services were once important to the CBD but are now less so. Changing shopping habits and residential patterns have reduced the importance of retail services in the CBD. In the past, three types of retail services clustered in the CBD because of its accessibility. These retail services include retailers with high thresholds, those with a high range, and those that served workers in the CBD. Changing shopping habits and residential habits have reduced the importance of retail services in the CBD.
Retailers with High Thresholds Retailers with a high range and threshold traditionally preferred a CBD location in order to be accessible to many people. Department stores with high thresholds are likely to be located in suburban malls.
Retailers with High Ranges High-range retailers are often specialized, with customers who patronize them infrequently. These retailers once preferred CBD locations because their customers were scattered over a wide area. Some retailers with high ranges have located in CBDs because they are visited by tourists. Some local residents also patronize shops in the CBD as a leisure activity on evenings and weekends.
Retailers Serving CBD Workers Specialized retailers and those serving downtown workers still remain in the CBD. Retailers selling office supplies, computers, and clothing or offering shoe repair, rapid photocopying, or dry cleaning are actually expanding in the CBD. The number of downtown office workers has increased, and downtown offices are now requiring more services. The total volume of sales in downtown areas has been stable, but the pattern of demand has changed.
Business Services in CBDs People in business services such as advertising, banking, journalism, and law depend on proximity with professional colleagues. Even with the diffusion of modern communications, many professionals still exchange information with colleagues primarily through face-to-face contact. A central location also helps businesses that employ workers from a variety of neighborhoods.
Competition for Space in CBDs A CBD’s accessibility produces extreme competition for the limited available land. As a result, land values are very high in the CBD. Because of intense competition for land, the CBD has distinctive features. The CBD has a three-dimensional character, with more space used below and above ground level than elsewhere in the urban area. Land uses commonly found elsewhere such as industrial and residential activities, are rare in the CBD. The CBD has a three-dimensional aspect with the use of spaces above and below ground level.
Removing Manufacturing from the CBD In the past, inner-city factories and retail establishments relied on waterfront CBDs that were once lined with piers for cargo ships to load and unload and warehouses to store goods. Port facilities have moved to more modern facilities downstream. Port cities have transformed their waterfronts from industry to recreational activities. Derelict warehouses and rotting piers have been replaced with new offices, shops, parks, and museums, becoming major tourist attractions.
Residents in the CBD Many people used to live downtown. Many people moved to suburbs pulled by the offer of larger homes with private yards and modern schools. They were pushed from CBDs by high rents that businesses and retail services were willing to pay and by the crime, congestion, and poverty that they experienced by living downtown. Downtown living has become attractive recently to people without school-age children. People without school-age children are attracted to the entertainment, restaurants, museums, and nightlife that is clustered downtown.
Vertical Features of the CBD The CBD makes more intensive use of space below and above ground.
The Vertical CBD: Underground A vast underground network exists beneath most CBDs. The typical “underground city” includes garages, loading docks for deliveries to offices and shops, electric and telephone wires, and pipes for water and sewer service. Subway trains run beneath the streets of large CBDs.
The Vertical CBD: Skyscrapers Skyscrapers developed to maximize the floor space in the highest-demand areas. Downtown skyscrapers give a city one of its most distinctive images and unifying symbols. The first high-rises caused great inconvenience to neighboring structures because they blocked light and air movements. Most North American and European cities enacted zoning ordinances early in the twentieth century in part to control the location and height of skyscrapers.
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Annexation Legally adding land area to a city in the United States.
Business service A service that primarily meets the needs of other businesses, including professional, financial, and transportation services.
Central business district (CBD) the main business and commercial area of a town or city The area of a city where retail and office activities are clustered.
Central city An urban settlement that has been legally incorporated into an independent, self-governing unit.
Central place A market center for the exchange of services by people attracted from the surrounding area.
Combined statistical area (CSA) an area with MSAs and µSAs that are close together and economically linked
Megalopolis A continuous urban complex in the northeastern United States.
Metropolitan statistical area (MSA) a geographical region with a relatively high population density at its core and close economic ties throughout the area.
Micropolitan statistical area (µSA) labor market areas in the United States centered on an urban cluster with a population at least 10,000 but less than 50,000
Public service A service offered by the government to provide security and protection for citizens and businesses.
Range the maximum distance that someone is willing to travel to receive a specific service
Service Any activity that fulfills a human want or need and returns money to those who provide it.
Site a way of describing where a place is based on the physical characteristics of the surrounding area
Threshold the minimum number of people needed for a service to be worthwhile
Urban area A dense core of census tracts densely settled suburbs, and low-density land that links the dense suburbs with the core. Urban cluster In the United States, an urban area with between 2,500 and 50,000 inhabitants.
Zoning practices local laws that define which types of economic activities can take place in specific areas of a city