According to the sector model of urban space, a city expands outward in a series of rings from a central point. The central location idea states that a city has more than one core around which activity swirl. These cores are generally considered to be the historical centers of town where most government offices and businesses are located. In modern cities, the central business district is often referred to as "the city center."
The concept of a central place was first proposed by French geographer Jean-Jacques Gérard in his 17th century work Essai sur l'histoire des peuples de la France. He argued that all great civilizations have had a single dominant city that served as their capital. His ideas were later taken up by other theorists such as Lewis Henry Morgan who published his work on this topic in 1877.
Central places are thought to have several advantages over peripheral sites. They are generally larger areas, providing more opportunities for social interaction. There also tends to be more diversity in terms of culture and use of space. Peripheral sites are usually smaller neighborhoods or even single buildings, which makes them more isolated from each other. This isolation can lead to problems with crime and maintenance if the site is not properly signed.
In reality, many cities have grown beyond the limits of their central places.
Burgess' concentric zone model describes the process of urban expansion as a succession of circular sectors or zones, each distinguished by a distinct form of land use, that expand from a central core. The model was first published in 1976 based on research conducted by American urban planner John R. Burgess.
The model assumes that cities grow in size following an expanding circle pattern. The central district is usually reserved for government offices, commercial districts, and other important institutions. Surrounding this core is an inner ring of residential neighborhoods. The next level out is called the business district, which typically includes large office buildings, shopping malls, hotels, and restaurants. Finally, at the edge of the urban area are parks and other open spaces. As cities expand they tend to do so gradually rather than in sudden bursts; thus, older parts of the city may remain relatively unchanged as new development surrounds them.
In the central district, high-density housing tends to be clustered near public services such as schools, hospitals, transportation hubs, etc. Residential density increases as you move away from the center, with low-density communities surrounding the business district and ending at the edge of the urban area with high-density apartments and houses.
The model suggests that there is a correlation between economic activity and land use.
The monocentric city model is a descriptive model of resource allocation in a city that was created to accurately describe such a phenomena. Its fundamental development took place in the 1960s and 1970s, particularly because to the efforts of William Alonso, Edwin Mills, and Richard Muth. The model has been widely used since its introduction in 1979 by Edward Glaeser to explain urban growth patterns.
This model focuses on the central business district (CBD) as opposed to other models that focus on specific neighborhoods within a city. The model assumes that there is only one CBD for each city, which means that no matter what part of the city you live in, you are still subject to the laws of gravity and thus will experience centralization over time.
There are two main assumptions behind the monocentric city model: first, that all cities follow the same pattern of growth and decline; second, that this pattern can be explained by looking at certain variables within the city itself. Under this model's framework, cities grow until they reach a critical mass where additional businesses decide to move in, thereby creating a cluster. This attracts more businesses, which leads to an escalation in population size and an increase in employment opportunities. When these clusters reach yet another critical mass, they become magnets for more people and companies, which further increases the size of the city.
A core city, also known as a metropolitan core or central city in urban planning, is the largest or most significant city in a metropolitan region. Smaller satellite cities, villages, and suburbs surround a central metropolis. Central cities are frequently the regional downtowns of metropolitan regions. They often contain government offices, major corporations, educational institutions, and cultural venues.
In North America, many large cities became central cities after the American Civil War, when municipal governments were formed to replace counties. The growth of industrialization and the migration of people from rural areas to larger cities created shortages of labor and housing that led to the emergence of new governmental structures designed to meet these needs. In general, these cities have very dense populations with a wide variety of cultural options available at any given time. They tend to have modern infrastructure including good public transportation systems.
In Europe, especially in Western Europe, many large cities became central cities after the Middle Ages, when they emerged as nodes within trade routes connecting them to other markets. At that time, urban centers were mainly located along the banks of navigable rivers, but this requirement was beginning to change with the development of new industries like textiles which used coal as a fuel and thus required a population able to transport goods over long distances.
The industrial revolution brought about new forms of transportation that made long-distance travel easier and allowed people to live outside the traditional center of town.