Introduction to Human Geography Using ArcGIS Online. J. Chris Carter
United States quickly impacted the global economy. Whereas music, fashion, and economic crises were once local phenomena or spread slowly, they now impact people around the world in a short period of time.
Spatial diffusion
Spatial diffusion is another way that characteristics spread to new locations. From an origin point, an idea or thing can diffuse to new places, where it can then combine with other ideas or things and form something new.
Spatial diffusion can be broken down into two broad categories: relocation diffusion and expansion diffusion.
Relocation diffusion occurs when people move to a new location and take their ideas and possessions with them. With relocation diffusion, the number of people using a particular idea or possession does not change, but the place where they are used does change. When Spaniards first migrated to the Americas, they brought their religious ideas and weapons with them. Thus, via relocation diffusion, Christianity and European military technology spread to the New World. This diffusion process occurred even before the indigenous people of the Americas began practicing Christianity and using steel weapons.
Likewise, Latin American culture has diffused to many parts of North America as Latino immigrants relocate north (figure 1.35). The Spanish language, food, music, and other cultural elements can now be found in many American and Canadian cities, specifically because of relocation diffusion.
Figure 1.35.Ecuadorian restaurant in New York. Latino immigrants bring their culture with them through the process of relocation diffusion. Photo by Lee Snider Photo Images. Stock photo ID: 426459184. Shutterstock.
Expansion diffusion occurs when the number of people using an idea or item increases. This type of diffusion resulted as Spaniards in the Americas converted the indigenous population to Christianity and the indigenous people began using and making steel weapons. Likewise, many nonimmigrants in North America now eat foods from Latin America and know a few words or phrases in Spanish (“Hasta la vista, baby”). Via expansion diffusion, culture and technology spread to new people.
Expansion diffusion can be broken down into contagious diffusion and hierarchical diffusion. Contagious diffusion is when a characteristic spreads from person to person on the basis of proximity. In a sense, it can be visualized as when a pebble is thrown in a pond and the waves move outward in a circular pattern (figure 1.36). Places close to the origin point adapt the new idea or item before places that are farther away do. Using the example of Spaniards in the Americas, the first indigenous people to be converted to Christianity and to use steel would be those who lived close to early Spanish settlements. Diffusion to indigenous people in more remote locations took much longer. Similarly, more people in the American Southwest than in other US areas eat dishes from Latin America due to their proximity to the southern border and Latino immigrant communities in southwestern cities. Over time however, Latino culture has spread to places beyond the border and immigrant-heavy cities. Guacamole is now a staple throughout the United States during the most all-American of events, the Super Bowl.
Figure 1.36.Contagious diffusion of Walmart. Contagious diffusion represents the outward spread from a point of origin, like rings emanating from a pebble falling in a pond. Explore the Walmart store openings dataset (1962−2006) in ArcGIS Online at https://arcg.is/0Cfy5a. Map by author. Data sources: Thomas J. Holmes. University of Minnesota, Federal Reserve Bank of Minneapolis, and NBER.
Hierarchical diffusion is when something spreads from a person or place of power and influence (figure 1.37). Geographers most often refer to hierarchical diffusion in terms of an urban hierarchy. If cities are ranked by population from large to small, it is more common for a new idea or item to originate in and diffuse to large cities first, then to medium-size cities, and later to small cities and towns. The latest musical trend or fashion typically begins in a large city, then diffuses to other large cities, even if they are far away—think New York, Los Angeles, London, and Paris. Medium-size cities will pick up on the trend a bit later, while diffusion to small towns will be later still.
In addition to urban hierarchies, diffusion can move along an income hierarchy, often from rich to poor. In most countries, the diffusion of things such as higher education, personal computers, and cars with airbags all began in households and neighborhoods with higher incomes. As time progressed, the cost of these innovations decreased, and they became more widely available in neighborhoods with lower income.
Stimulus diffusion is when a characteristic spreads to a new place, but rather than remaining in its original form, it stimulates a new innovation. For example, US fast-food restaurants have diffused around the world, but those that have been most successful have modified their menus to reflect local culture. For example, rather than a simple diffusion of burgers and fries to Japan, McDonald’s offers crab croquette burgers and fries with white and dark chocolate sauce. McDonald’s is a global company, but its diffusion worldwide has stimulated innovation in new menu items. In a similar sense, the idea behind ride-hailing services such as Uber has stimulated new services for hailing rickshaws in India.
Figure 1.37.Hierarchical diffusion of a hypothetical trend. Geographers often study hierarchical diffusion in terms of urban hierarchies. New trends and products originate in large cities, then diffuse to medium and small cities over time. Maps by author. Data sources: Esri, HERE, Garmin, NGA, USGS.
Diffusion processes do not flow unimpeded across the landscape but rather face barriers to diffusion. Barriers can be physical or cultural. Mountains, oceans, rivers, dense forests, and deserts can act as physical barriers that slow or stop diffusion. Physical barriers can also include walls, trenches, and other human-built features. Cultural barriers can be just as powerful in stopping or slowing diffusion. Language, race and ethnicity, religion, income, and other cultural differences can limit communication and interaction between groups of people, thus inhibiting the diffusion of ideas and items from one community to another, be it religion and philosophy, music, disease, or technology. Furthermore, cultures that are more conservative and tradition-based will resist the diffusion of new ideas and items from other people and places. The Taliban’s prohibition of modernity in terms of music, technology, clothing, and much more limits diffusion into areas under its control.
Go to ArcGIS Online to complete exercise 1.6: “Origin, spatial diffusion, and spatial interaction.”
Human–environment interaction
The ecological perspective: Cultural ecology
As discussed so far, we have seen how spatial patterns are created from the interaction between places and the diffusion of things over space. But these patterns are also the result of another type of relationship studied by geographers: human-environment interaction. The interaction between humans and the environment is known as the ecological perspective, or cultural ecology—the interplay of human cultures with ecological patterns.
Figure 1.38.Garbage-filled harbor in Malaysia. Humans’ actions often have a profound negative impact on the environment, threatening the health of people and wildlife alike. Photo by Rich Carey. Stock photo ID: 214284142. Shutterstock.
Humans impact the environment in many ways. They alter plant and wildlife distributions by converting natural habitats to farms and cities; they change the course of rivers through dams and canals; they alter the quality of air, water, and soils through pollution; and they remove hills and fill valleys for development projects (figure 1.38). Very few places are free of human impacts, and with human-induced climate change, the distributions of plants, animals, crops, and human settlements are likely to be further transformed at a global scale.
Similarly, the environment impacts humans. Human settlements tend to be