People seldom live in isolation. Most reside in settlements, which vary greatly in size, composition, location, arrangement, and function. These organized groupings of human habitation are the focus of most aspects of human life: economic activities, transportation systems, communications media, political and administrative systems, culture and entertainment. Therefore, to be geographically competent—to appreciate the significance of geography’s central theme that Earth is the home of people—a person must understand settlement processes and functions and the patterns of settlements across Earth’s surface.

Settlements exercise a powerful influence in shaping the world’s different cultural, political, and economic systems. They reflect the values of cultural groups and the kinds of political structure and economic activity engaged in by a society. Accordingly, the patterns of settlement across Earth’s surface differ markedly from region to region and place to place. Of great importance to human existence, therefore, are the spatial relationships between settlements of different sizes: their spacing, their arrangement, their functional differences, and their economic specialties. These spatial relationships are shaped by trade and the movements of raw materials, finished products, people, and ideas.

Cities, the largest and densest human settlements, are the nodes of human society. Almost half of the world’s people now live in cities, and the proportion is even higher in the developed regions of the world. In the United States, more than three-quarters of the people live in urban areas. More than two-thirds of the people of Europe, Russia, Japan, and Australia live in such areas.

Cities throughout the world are growing rapidly, but none so rapidly as those in developing regions. For example, the ten largest cities in the world in the year 2000 will include such Latin American cities as São Paulo and Mexico City. In some regions of the world there are concentrations of interconnected cities and urban areas, which are known as megalopoli. In Japan, the three adjacent and continuous cities of Tokyo-Kawasaki-Yokohama make up such a megalopolis. In Germany there is another, consisting of the Rhine River Valley and the cities of Essen, Düsseldorf, Dortmund, and Wuppertal. The corridor from Boston to Washington, D.C., is also a megalopolis (sometimes called Megalopolis because it was the first one to be designated).

Cities are not the same all over the world. North American cities, for example, differ from European cities in shape and size, density of population, transportation networks, and the patterns in which people live and work within the city. The same contrast is true of cities in Africa, Latin America, and Asia. For example, in North American cities wealthy people tend to live in the outskirts or suburban areas, whereas lower income residents tend to live in inner-city areas. In Latin America the spatial pattern is reversed: wealthy people live close to the city centers, and poor people live in slums or barrios found at the edges of urban areas.

In North America, Europe, and Japan urban areas are linked to one another by well-integrated, efficient, and reliable transportation and communication systems. In these regions, even the smallest villages are linked in a web of trade, transportation, and communication networks. In contrast, in developing regions such as Latin America and Southeast Asia, a single primate city often dominates the life of the country. A primate city such as Buenos Aires or Manila is preeminent in its influence on the culture, politics, and economic activities of its country. Nevertheless, in terms of transportation and communications links it may be better connected to the outside world than it is to other regions of the country it serves.

Settlements and the patterns they etch on Earth’s surface provide not only data on current economic and social aspects of human existence but also a historical record. Today’s settlement patterns, evident on a map, provide information about past settlement patterns and processes, and the boundaries of counties and other political entities indicate how people organized the land as they settled it. In all such cases, the surviving evidence of past settlements can and should be amplified by the students’ use of research materials to develop a fuller understanding of how settlements relate to their physical settings over time. It is valuable, for example, to know about life in a German medieval town and the town’s relationship to the surrounding countryside; life in a typical North Dakota settlement along a railroad line in the 1890s; and life in the walled city of Xian and the city’s importance in north China in the second century B.C.

Students must develop an understanding of the fundamental processes, patterns, and functions of human settlement across Earth’s surface, and thereby come to appreciate the spatially ordered ways in which Earth has become the home of people. They need to acquire a working knowledge of such topics as: the nature and functions of cities, the processes that cause cities to grow and decline, how cities are related to their market areas or hinterlands; the patterns of land use and value, population density, housing type, ethnicity, socioeconomic status, and age distribution in urban areas; the patterns of change, growth, and decline within urban areas; the process of suburbanization; and how new types of urban nodes develop. Geographers ask these questions to make sense of the distribution and concentrations of human populations.