Remote Sensing

Geographers are keen in using fieldwork as part of their professional toolkits for understanding the world. Fieldwork can be quite laborious, costly, and—sometimes—dangerous. Since the middle of the 20th century when aerial photography became widely available, geographers have made frequent use of remote sensing. Remote sensing is a term that refers to a set of techniques by which the environment is studied. Electromagnetic radiation is sensed by devices as it is reflected, refracted, scattered, transmitted, and emitted by matter in the environment. Each feature of Earth and the atmosphere has a “spectral signature,” that is, the interaction of the various electromagnetic wavelengths with that feature. Thus, we are able to identify,measure, andmodel features that are not in physical contact with the features under study. 

There aremanymeasurement devices that are in direct contact with what they are measuring and so, by definition, are not remote sensing devices. A thermometer is not a remote sensing device for air temperature because its temperature readings are dependent on the collision of atmospheric molecules with the device. A thermal radiometer, however, can be mounted in a satellite and measure the temperature in the atmosphere it is not touching. Table 3 illustrates the types of remote sensing commonly used by geographers, primary wavelengths involved, and typical uses. The most well-known and commonly used form of remote sensing is photography. 

A camera contains film sensitive to light. The film is kept in the dark until the lens is opened to expose the film. The image is made permanent by developing it with chemicals. Aerial photography is of oblique and vertical types. Oblique photography is the perspective we see looking out of an aircraft window. Much more useful to the geographer is vertical photography in which the camera is pointed underneath the aircraft and features can be mapped and measured.

Religious Syncretism

Religious syncretism occurs when the characteristics of two or more faiths blend to alter one of the faiths, or to create a completely new religion. This is usually the result of cultural diffusion, when a new religious worldview encounters the established set of sacred precepts already present in a given region. The process of syncretization, or the incorporation of new rituals, dogma, or concepts, may be voluntary or enforced. The process of religious syncretism frequently leads to alterations in the sacred space of a location, as new religious structures may be built, or existing ones changed to suit the changes brought about by the integration of new beliefs. This may involve the establishment of entirely new sacred locations, or it may mean the use of previous sacred spaces, but with a modification of their former characteristics, relevance, or importance in the new religious system.

Religious syncretism is often viewed by at least some believers as a threat to the “purity” of religion, and an attack on orthodoxy and tradition. Those who support the syncretic process are sometimes labeled heretics and accused of undermining the principles of the faith. However, most faiths indicate at least some ideas or practices that have been borrowed from other religious traditions, and the process of religious syncretism may be so subtle and lengthy that it is not recognized by believers. On the other hand, some faiths have been specifically created on the basis of incorporating the “best” elements from others.

Rain Shadow Effect

A rain shadow is a landscape-induced, long-term relative lack of precipitation of an area compared to its geographic surroundings. Rain shadows exist because the landscape “gets in the way” of the horizontal flow of air. Air cannot reverse direction when it encounters significant topography. Thus, it must stop, flow over, or flow around the barrier; this has a significant influence on patterns of precipitation. The orographic effect is an enhancement of precipitation because of the rise of air over the topography. A rain shadow can be viewed as the muting of precipitation because of the landscape. Frequently, the orographic effect and rain shadows occur in tandem.

Precipitation occurs because air containing water vapor rises and cools. The air cools until it becomes saturated, clouds are formed, and then precipitation processes cause some of the water in clouds to fall toward Earth. One type of rain shadow occurs because of the strong descent of air. If stable air has been topographically lifted to the crest of a mountain, it will attempt to sink back to its original, unlifted altitude after it crests the mountain. It will undergo adiabatic warming at 10°C per every kilometer of descent because, even if originally saturated at the mountain crest, the air quickly becomes unsaturated. Adiabatic warming increases the air’s capacity to hold water vapor and decreases its relative humidity sharply away from saturation. Without a significant rise of air, the potential for precipitation is smaller and the area’s dryness enhanced by greater solar radiation due to the relative lack of clouds.

A second type of rain shadow is formed as moist air encounters topographic barriers but does not have the dynamics to rise over the barrier or divert around it. In this case the air pools in front of the barrier and the land in the lee of the barrier does not receive the moist air.

A third type of rain shadow is formed when air encounters higher terrain but is able to divert around it at low elevations. For instance, Pacific air encounters the Olympic Mountains in Washington State and is able to flow around them through the Strait of Juan de Fuca to the north and a near-sea-level lowland to the south. The result is that east of the Olympics—near the western reaches of Puget Sound—the precipitation is significantly less than in the mountains. Embedded within a regional climate of many cloudy days with light precipitation, the locals jokingly label this part ofWashington “the banana belt.” Port Townsend directly downwind of the OlympicMountains receives a bit over 65 cm (26 in) of precipitation. To the east of Puget Sound, Seattle receives nearly 100 cm (40 in) of precipitation because the air streams that have flowed around the Olympic Mountains are able to converge and cause the rise of air.

Sustainable Development

A philosophy and set of behaviors that strive to find methods of maintaining current quality of life while simultaneously minimizing the degradation of environmental and social systems to perpetuate these systems for future generations. The term “sustainable development” is sometimes generally associated with the stewardship of natural resources and preservation of wildlife habitats. Certainly wise and judicious use of energy and other products, and maintaining a balanced approach to the exploitation of ecosystems, is one of the core goals of the philosophy, but the concept is considerably broader than just these objectives and extends beyond just environmental concerns. Indeed sustainable development is a holistic notion designed to achieve a state of equilibrium between development and conservation across the spectrum of human experience. Advocates of sustainability seek to avoid the pitfalls and degradational consequences of the tragedy of the commons, a situation in which a resource is mismanaged and potentially lost because of a lack of communal oversight and concern. Both raising awareness and implementing practice are vital to achieving sustainability, and the United Nations has been a strong proponent of the concept, especially through the vehicle of the UN Earth Summit meetings held in Rio de Janeiro in 1992 and Johannesburg in 2002. The meeting in Rio generated Agenda 21, a detailed set of objectives meant to promote and highlight the potential benefits of sustainability, as well as to articulate mechanisms for reaching an equilibrium of production and consumption economically, ecologically, and socially.

Supranationalism

A form of political organization that partially transcends the sovereignty of its constituent units, increases the permeability of their boundaries, but that falls short of becoming a complete federation, in that the states so incorporated retain a significant measure of political independence. A cluster of states that joins together to promote trade and economic development, or to enhance their collective security, is not necessarily a supranational group. To reach this distinction, a greater degree of integration beyond simply promoting mutual interests must be sought and achieved. Some commentators consider supranationalism to be a form of political globalization. 

The first use of the term in a legal document appears to be in the Treaty of Paris in 1951, which formally established the European Coal and Steel Community (ECSC), setting the stage for the creation of the European Economic Community (EEC) with the promulgation of the Treaty of Rome in 1957. After adding members steadily for several decades, the EEC became the European Union (EU) under the Masstricht Treaty in 1994. Other international organizations may be “supranational” to a limited extent, but to date the European Union remains the most ambitious example of supranationalism.

The motivation behind the drive toward supranationalism in the European region has several points of origin. In the aftermath of World War II European countries sought some mechanism beyond simple treaties to ensure a lasting peace on the continent and to avoid a repetition of the massive destruction of the first half of the 20th century. Economic integration was viewed as such a mechanism, because by tightening economic (and ultimately, political) ties, the basis for conflict would be undermined, a notion that is the foundation of economic peace theory in the field of international relations. This is made quite clear in the famous statement by the French politician Robert Schuman, in which he held that economic integration would make war “materially impossible” in Europe. 

In addition, some of the smaller European countries were at a disadvantage in competing against the larger economies and sought to cooperate as a larger, single economic space to be more competitive. This was the case with the Benelux customs union, formed in 1948 between Belgium, the Netherlands, and Luxembourg. The reduction of customs duties and other impediments to trade between the Benelux countries led to rapid economic growth and other benefits, and the Benelux union along with the ECSC provided the basis for further integration. The three Benelux states then joined with the larger economies of West Germany, Italy, and France in forming the EEC. The EEC was much more than a simple customs union, because from an early point it attempted to coordinate economic policy among its members, some of whom initially resisted what they viewed as efforts to erode their national sovereignty.

Stream Erosion and Deposition

Streams are predominant shapers of the terrestrial landscape. Main streams and their innumerable tributaries are responsible for much of the landscape we see. Even in arid areas, stream water can do significant work when available because of the lack of protective vegetative cover fostering increased surface erosion and runoff. In the absence of significant tectonic disturbance, the overall effect over very long amounts of time is to make the higher places lower by erosion and lower places higher thus “smoothing” the landscape. Within the immense time scale related to smoothing it is common for streams to produce hills, valleys, and canyons by lengthening, deepening, and widening their valleys.

The landscape has been given a simple classification vis-a`-vis stream erosion. The surface area drained by a stream is a drainage basin (or a watershed) and its boundaries are drainage divides. Drainage basins exist on vastly different scales and, because streams have tributaries, main streams are associated with the multitude of tributary drainage basins that are nested at various scales one within another. It is through the organization of drainage basins that the flows of mass and energy associated with streamerosion and deposition can be understood. Stream-produced landscapes are segmented into interfluves, valley sides, and valley bottoms. High ground dividing adjacent river valleys is known as an interfluve. At the highest elevation along an interfluve is a drainage divide. Interfluves can be many kilometers across or nonexistent in the case of drainage basins edged by steep mountains. The valley side is the increased slope down to the valley bottom. Valley sides can have slopes of only a few degrees from horizontal or be bluffs or canyon sides. The valley bottom is the surface along which a stream is eroding or depositing and can be negligible such as on a canyon bottom or many kilometers wide.

Squatter Settlements

Areas of dense, low-quality housing around many large cities in the developing world, usually formed by illegal occupation, or “squatting,” of unclaimed land. Squatter communities are created by the migration of poor, rural residents to cities who are drawn there by the push-pull concept, especially the allure of higherpaying jobs. Over the past forty years many urban areas in the developing world have witnessed a surge in new arrivals from the hinterland they serve, and the supply of local housing has simply been unable to keep pace with the increase in population. New residents have therefore been forced to build ramshackle sheds on unclaimed or public land. 

Globally, an enormous number of people live in squatter settlements, with some estimates running as high as one billion, and in some cities the residents living in such conditions may approach one-quarter of the population, although exact figures for the number of people living in local squatter neighborhoods are frequently difficult to obtain. In the Spanish-speaking countries of Latin America squatter settlements are locally referred to as barrios, while in Brazil a community of illegal residents is called a favela. The city of Sao Paulo, Brazil’s most populous city, has more than 600 of these settlements, and the United Nations estimates that about 26 percent of Brazil’s total population lives as squatters. In South Africa the local squatter settlements are called shanty towns.

The shanty towns found around South African cities have expanded exponentially over the past 20 years, due to the elimination of the laws that prohibited blacks from settling in many urban areas. Under the system of apartheid, the white-dominated government had created some squatter communities by forcefully relocating illegal residents to maintain racial segregation in urban areas; but as apartheid was dismantled, many rural blacks migrated to the cities and established new shanty towns. 

Regardless of where the squatter settlement is located, all such developments share some basic characteristics. Housing is inferior, often built haphazardly on unstable ground like the sides of hills and ravines. Building materials are usually scrap wood and sheet metal, cardboard and plastic. Most of the structures lack flooring, and frequently thousands of shacks, perhaps homes to ten thousand people, are constructed without any plumbing. Because the settlement is illegal and unplanned, in most cases streets are unpaved, narrow, and lack any naming system or other means of identification, just as individual residences have no numeral system of location. Running water is often available only at some distance, because water lines are usually not supplied to squatter settlements by municipal governments, and communal spigots are frequently the only source of water.