Political borders Political borders are imposed on the world through human agency. That means that although a political border may follow a river or mountain range, such a feature does not automatically define the political border, even though it may be a major physical barrier to crossing. Political borders are often classified by whether or not they follow conspicuous physical features on the earth. William Miles said that Britain and France traced close to 40% of the entire length of the world's international boundaries.
Natural borders separates the two countries. Natural borders are geographical features that present natural obstacles to communication and transport. Existing political borders are often a formalization of such historical, natural obstacles. Some geographical features that often constitute natural borders are: •
Oceans: oceans create very costly natural borders.
Very few countries span more than one
continent. Only very large and resource-rich states are able to sustain the costs of governance across oceans for longer periods of time. •
Rivers: Some political borders have been formalized along natural borders formed by rivers. If a precise line is desired, it is often drawn along the
thalweg, the deepest line along the river. •
Lakes: larger lakes create natural borders. •
Forests: denser jungles or forests can create strong natural borders. •
Mountain ranges: Many nations have their political borders defined along mountain ranges, often along a
drainage divide. Throughout history, technological advances have reduced the costs of transport and communication across the natural borders. That has reduced the significance of natural borders over time. As a result, political borders that have been formalized more recently, such as those in Africa or Americas, typically conform less to natural borders than very old borders, such as those in Europe or Asia, do.
Landscape borders A landscape border is a mixture of political and natural borders. One example is the defensive forest created by China's
Song dynasty in the eleventh century. Such a border is political in the sense that it is human-demarcated, usually through a
treaty. However, a landscape border is not demarcated by fences and walls but instead landscape features such as forests, mountains, and water bodies. It is different from a natural border, however, in the sense that the border landscape is not natural but human-engineered. Such a landscape usually differs from the borderland's natural geography and its building requires tremendous human labour and financial investment.
Geometric borders Geometric boundaries are formed by straight lines (such as lines of longitude), or occasionally arcs (such as lines of latitude or the Pennsylvania/Delaware border), regardless of the physical and cultural features of the area. Such political boundaries are often found around the states that developed out of colonial holdings, such as in
North America,
Africa and the
Middle East. The
Canada–United States border follows the 49th parallel for roughly from
Lake of the Woods (
Ontario and
Minnesota) west to the
Pacific Ocean.
Fiat borders A generalization of the idea of geometric borders is the idea of
fiat boundaries by which is meant any sort of boundary that does not track an underlying
bona fide physical discontinuity (
fiat,
Latin for "let it be done", a decision). Fiat boundaries are typically the product of human demarcation, such as in demarcating electoral districts or postal districts.
Relic borders was to stop people and militaries from crossing the northern border of China. Today it is a relic border. A relic border is a former boundary, which may no longer be a legal boundary at all. However, the former presence of the boundary can still be seen in the landscape. For instance, the
boundary between
East and
West Germany is no longer an international boundary, but it can still be seen because of historical markers on the landscape; it remains a cultural and economic demarcation in
Germany. Other examples include the
Demilitarized Zone between
North and
South Vietnam (defunct since 1975) and the border between
North and
South Yemen (defunct since 1990). Occasionally a relic border is reconstituted in some form, for example the border between
British Somaliland and
Italian Somaliland ceased to exist when the two colonies merged to form the independent state of
Somalia in 1960, however when the former British Somaliland declared independence in 1991 it claimed the former British-Italian line as its eastern border.
Lines of control A
line of control (LoC) refers to a militarized buffer border between two or more nations that has yet to achieve permanent border status. LoC borders are typically under military control and are not recognized as an official international border. Formally known as a cease-fire line, an LoC was first created with the
Simla Agreement between
India and
Pakistan. Similar to a cease-fire line, an LoC is typically the result of war, military stalemates and unresolved land ownership conflict.
Maritime borders A maritime border is a division enclosing an area in the ocean where a nation has exclusive rights over the mineral and biological resources, encompassing maritime features, limits and zones. Maritime borders represent the jurisdictional borders of a
maritime nation and are recognized by the
United Nations Convention on the Law of the Sea. Maritime borders exist in the context of
territorial waters,
contiguous zones, and
exclusive economic zones; however, the terminology does not encompass
lake or
river boundaries, which are considered within the context of land boundaries. Some maritime borders have remained indeterminate despite efforts to clarify them. This is explained by an array of factors, some of which illustrate regional problems.
Airspace borders Airspace is the
atmosphere located within a country's controlled international and maritime borders. All
sovereign countries hold the right to regulate and protect air space under the international law of
Air sovereignty. The horizontal boundaries of airspace are similar to the policies of "
high seas" in maritime law. Airspace extends 12 nautical miles from the coast of a country and it holds responsibility for protecting its own airspace unless under
NATO peacetime protection. With international agreement a country can assume the responsibility of protecting or controlling the atmosphere over International Airspaces such as the
Pacific Ocean. The vertical boundaries of airspace are not officially set or regulated internationally. However, there is a general agreement of vertical airspace ending at the point of the
Kármán line. The Kármán line is a peak point at the altitude of 62 mi (100 km) above the Earth's surface, setting a boundary between the atmosphere (airspace) and
outer space (which is governed by
space law).
Frontier The frontier is a border that is open-ended to one side, identifying an expanding borderland to one side. This type of border can be fairly abstract and has been identified as a particular state of mind for human activity. As such frontiers have been applied to borderlands identifying and claiming them as
terra nullius, such as
Marie Byrd Land in
West Antarctica, the only territory in Antarctica unclaimed by any sovereign nation. == Types of border regulation ==