Humidity

Humidity refers to the water vapor content of the atmosphere. Usually, this term does not include the water held as liquids and solids in clouds and precipitation. Instead, water vapor is the gaseous form of water. It is odorless and colorless, but significant amounts of humidity can impair visibility. Water vapor is one of the gases of the atmosphere and freely mixes and moves in the fluid flow we call wind. 

To persist in the form of a gas, water must achieve much higher energy content than the liquid or solid states. In the dynamic setting of the free atmosphere water readily changes state to and from its gaseous phase. When vapor changes phase to liquid, this process is called condensation and the water molecules organize themselves into chains because of loss of energy from the vapor. Conversely, when water evaporates and changes its phase from liquid to vapor, this necessitates the addition of substantial amounts of energy to break the chains of liquid molecules.

Less well known to most of us is that water vapor can lose enough energy at once to change directly from gas to the regular crystalline arrangement of ice molecules; this process is called deposition and the result can be witnessed as the accumulation of frost on an automobile on a clear winter night. In reverse, ice can directly change to water vapor by gaining enough energy; this process is called sublimation and can be subtly observed by noting the decrease in an ice or snow cover after windy conditions; even when temperatures are below 0°C, ice can sublimate into water vapor.

The energy inherent to water vapor that allows water vapor to remain as water vapor is known as latent heat. This name implies that the heat is “hidden” and not directly detectable by thermometer. At sea level, the conversion of ice to water vapor requires about 2,850 joules. This is energy lost from the water’s surroundings and converted into hidden, latent form. The latent heat remains with the water vapor until condensation or evaporation takes place. These processes may take place many thousands of kilometers from where the vapor was added to the air. The latent heat effect can be quite dramatic. When water changes phases from vapor to liquid or solid, the release of latent heat can warm the atmosphere. If this phase change is ongoing while air is rising latent heat release retards the adiabatic cooling, making the air rise to much greater heights than it would without this phase change. Latent heat provides the huge amounts of energy needed for thunderstorms and hurricanes.

Hinterland

Hinterland is a term that may be used in several ways in geography. It has a more specific meaning to economic geographers, when it is used to designate the region that is economically connected to an economic urban hub, usually a port or city. In this context the “hinterland” in effect refers to the market area, or distribution area, for the economic center. It may also be used in a general way to identify a region generally devoid of urban development that extends beyond the margin of such development but is still influenced by it. In the core and periphery concept, the term “hinterland” is often used interchangeably for the periphery, and therefore makes up the outer margin of a functional region. The word is sometimes used in reference to political control as well, to indicate a zone beyond the formal political or legal boundaries of a state or other political unit, but nevertheless swayed by its policies.

In a more general sense, the term is equivalent to other English terms such as “backwoods,” “outback,” “frontier,” and “back country.” Hinterland used in this way often characterizes an undeveloped region located inland from a strip of coastal settlement. 

In economic geography an entrepoˆ t is often considered to have a hinterland. The hinterland region is the larger market space through which the goods and services provided by the entrepoˆ t are dispersed. It is also the region that may provide raw materials for export to the entrepoˆ t. The size and function of the hinterland will modify, depending on the rate of growth (or lack thereof) of the entrepoˆ t. Lower-order economic centers may emerge in the hinterland, which function as distribution centers for the larger entrepoˆt, and often acquire secondary production functions, sometimes developing hinterlands of their own on a smaller scale.

The concept of an economic hinterland is a key part of Central Place Theory. Each central place is serviced by a hinterland, or market area. The size of the hinterland is determined by the range of the good or service in question—the hinterland’s radius is the equivalent to the range of the good or service in question. The range of a good or service is the distance that consumers will travel to access it. Different types of goods have different ranges. So-called higher-order goods and services, like automobiles, dental care, legal advice, etc., that are expensive and are used infrequently will have a large range, and therefore a much larger hinterland associated with them than lower-order goods. Lower-order goods, like a loaf of bread, gasoline, a car wash, etc., are used frequently and are generally inexpensive. These have a small range, and the hinterland connected to such goods and services is much smaller than with higher-order products. Thus, there is a hierarchy of hinterlands, with smaller hinterlands (lower-order goods and services) clustered within the hinterlands of higher-order goods and services. Central Place Theory suggests that these hinterlands are not circular, but rather take the form of hexagons.

Heartland Theory

A theory of geopolitics proposed by J. Halford MacKinder at the beginning of the 20th century. MacKinder taught geography at Oxford University and served in the British parliament for 12 years and was well connected to the policymakers and strategic thinkers of his time. Great Britain was still the world’s foremost power when MacKinder put forth his ideas, and it is clear that he viewed British imperialism as the most moral and just among the European empires. It is likely that he was deeply influenced by notions of the “Great Game” between Russia and Great Britain that had motivated British policy in south Asia during the second half of the 19th century. MacKinder believed that the heartland theory was in reality a roadmap to global domination in an age when Britain’s preeminent position in international affairs was being challenged by emerging powers such as Germany and Russia. His ideas are firmly rooted in territoriality, as he held that control of a key geographic space was essential to political power.

MacKinder first publicly presented his theory to the Royal Geographical Society (RGS) in 1904. The title of his paper was “The Geographical Pivot of History,” which was published later the same year. In this discussion MacKinder analyzed the distinction between, and relative merits of, “land power” versus “sea power.” Moreover, he sought to identify a larger geographical relationship to historical events, postulating a “geographical causation in universal history.” He suggested that the Eurasian landmass was the key to global political power, represented by a core “pivot region” that encompassed much of Eastern Europe, Central Asia, and extended across northern Russia. This “geographical pivot” region, according to the theory, had been from ancient times the key to territorial control of greater Eurasia, although during the “Columbian epoch,” as MacKinder termed the previous four hundred years, the importance of dominating the pivot region had temporarily been overshadowed by the rise of sea power. MacKinder acknowledged that the dominance of the high seas by the English navy had been vital to the construction of the British Empire, but argued that the development of extensive railway networks in Asia would offset the advantages of controlling the world’s sea lanes and choke points. The Russian empire had begun construction of the Trans-Siberian Railroad about a decade earlier, and this development very likely convinced MacKinder that the vast expanses of Asia could be connected via rail. His thesis also was influenced by organic theory, as he spoke of history and physical geography as being “organically connected,” and there are clear undertones of environmental determinism in his ideas regarding the relationship of history and physical geography.

Irredentism

The desire of a state to “recover” territory previously lost to another state, typically on the basis of uniting similar ethnic groups or on the grounds of prior historical claim. Irredentism is a policy rooted in territoriality and the organic theory of the state, and had a profound effect on the geopolitics of the 19th and 20th centuries. Irredentism is a common aspect of the foreign policies of countries occupying a shatterbelt, because boundaries often shift in such locations, leaving ethnic groups divided among two or more nation-states. A synonym is revanchism, a term derived from the French word revanche, meaning “revenge.” Irredentism comes from the Italian term irredenta, which referred to lands populated by ethnic Italians that were not incorporated into the Italian state during the Risorgimento, or Italian unification, during the 19th century. A number of such territories existed, including Trieste, Nice, and Corsica. Several of the irredenta lay within the Austro-Hungarian Empire, and the Italian government entered World War I on the side of the Allied Powers with the expectation that a defeat of the Austrians would open the way for the absorption of these places into Italy. Over the course of the 20th century, several of the disputed territories in fact were included in the boundaries of Italy. The collapse of empires usually results in the expression of irredentist motives on the part of the remnant states, since the existing cultural landscape of ethnicity rarely correlates directly with the new political borders marking off the new states.

Karst

Karst is an unusual word used to describe an interesting set of landforms and landforming processes. The word is the Germanic version of the Slovenian Kras, which refers to a particular limestone plateau in Slovenia and Italy that was named for being barren. It was there that the classic scientific descriptions of the landscape were made and, so, the Kras landforms were used as archetypes for features in many other places in the world. Several other languages, including Latin and Chinese, have their own terminologies, but the scientific community uses karst and other words to describe the landforms of the Kras Plateau or to any similarly formed surfaces.

Karstic landscapes are widely spread and found in areas underlain by particular rock types, structures, and goodly amounts of precipitation under tropical and middle latitude temperature conditions. Additionally, some of today’s areas are the products of paleoclimates no longer in existence at those locations. Prominent areas of karst are found in Morocco, the United Kingdom, France, Australia, China, Slovenia, Italy, the United States (the Ozarks, Appalachians, and Florida), Russia (Urals and eastern Siberia), Brazil, Mexico, Costa Rica, South Africa, Namibia, Thailand, Vietnam, and Papua New Guinea. It must be recognized, though, that karst regions represent a minority of the surface areas of these places. Karst landscapes can be quite rugged or very gentle depending on the subsurface rock, amount of precipitation, and the length of time over which the landscape has evolved.

Locational Analysis

A theory and methodology of spatial relationships, their flows and interrelationships that served as the core of the quantitative revolution. The intellectual approach of locational analysis did not arise with the new momentum of the revolution in the late 1950s, but could be found in much earlier efforts to investigate patterns manifest in space that appeared rational and explicable. The von Thunen model of agricultural land use is an example from more than a century earlier, and the work of theorists working in both urban and economic geography in the first decades of the 20th century may be taken as precursors of the later focus as well. Those scholars who promoted locational analysis as a framework for geographical study employed an array of mathematical and statistical techniques, including multivariate analysis, probability models, and other aspects of what was later termed “geomatics.”

Academic departments of geography in which locational analysis became prominent as a philosophy of spatial inquiry pioneered the use of early computers as a means of evaluating the patterns of spatially arranged data. This cutting edge technology solidified the claim for many university administrators and federal agencies that locational analysis was a more scientifically based kind of geography, and at least for a time garnered the young scholars who were the foremost practitioners of the methodologies support in the form of grants and contracts, as well as acceptance in many of the leading scholarly journals. Locational analysis became the primary set of methodologies in economic and urban geography and was widely used in the study of population dynamics, migration, and related topics.

Linguistic Geography

One of the “pillars” of human culture is a complex language. Human language and dialects are spatially distributed over the Earth’s surface, and linguistic geography is the study of this distribution. Geographers who focus on the locational dynamics of language may examine many aspects of linguistic diversity. Where are the boundaries of language families, how do languages migrate across space, and what is the relationship between language and cultural identity are only a few of the relevant questions that linguistic geography addresses. Linguistic landscapes are constantly changing on multiple scales, a fact that forces linguistic geographers to approach their subject in a variety of methodological ways, and from a range of perspectives. Linguistic geography may involve the study of a local dialect, a national language, the relationship among languages in a given place, the impact of English as a global lingua franca, or many other characteristics of spoken and written communication.

Languages and dialects typically dominate a given space, or language region. The location of such regions is frequently changing and is not always determined simply by political boundaries. In addition, variations in dialect and usage may often be associated with a specific space. There are almost 7,000 languages spoken in the world today, but approximately 500 of these tongues are classified as “near extinct,” meaning that there are only a few individuals who continue to speak and/or write the language. Hundreds of languages have died out over the course of history, but in many cases remnants of such tongues continue to “survive” in living languages. For example, Latin is often labeled a “dead language,” but in fact dozens of phrases in English are either directly incorporated from Latin or are modified forms of the original word. In specialized fields such as law, Latin phrases such as pro bono, quid pro quo, and habeas corpus are part of the everyday vocabulary. Languages move through space by the process of cultural diffusion, and the historical migration of ethnic groups may sometimes be traced through linguistic connections. It is believed that successive waves of Celtic, Germanic, and later Slavic peoples all migrated into Europe from western or central Asia, because of the linguistic linkages these groups share with other speakers of Indo-European languages. The migration pattern of peoples like the Zulu in southern Africa may be identified in a similar fashion, through similarities with other groups using Bantu tongues. Thus linguistic geography articulates both contemporary language patterns and those of the past in many instances.