geography Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and ...

, the

centroid In mathematics and physics, the centroid, also known as geometric center or center of figure, of a plane figure or solid figure is the arithmetic mean position of all the points in the surface of the figure. The same definition extends to any ob ...

of the two-dimensional shape of a region of the Earth's surface (projected radially to sea level or onto a

geoid The geoid () is the shape that the ocean surface would take under the influence of the gravity of Earth, including gravitational attraction and Earth's rotation, if other influences such as winds and tides were absent. This surface is extended ...

surface) is known as its geographic centre or geographical centre or (less commonly) gravitational centre. Informally, determining the centroid is often described as finding the point upon which the shape (cut from a uniform plane) would balance. This method is also sometimes described as the "gravitational method". One example of a refined approach using an azimuthal equidistant projection, also potentially incorporating an iterative process, was described by Peter A. Rogerson in 2015. The abstract says "the new method minimizes the sum of squared great circle distances from all points in the region to the center". However, as that property is also true of a centroid (of area), this aspect is effectively just different terminology for determining the centroid. In 2019, New Zealand's

GNS Science GNS Science ( mi, Te Pū Ao), officially registered as the Institute of Geological and Nuclear Sciences Limited, is a New Zealand Crown Research Institute. It focuses on geology, geophysics (including seismology and volcanology), and nuclear sc ...

also used an iterative approach (and a variety of different projections) when determining a centre position for New Zealand's Extended Continental Shelf. However, other methods have also been proposed or used to determine the centres of various countries and regions. These include: * centroid of volume (incorporating elevations into calculations), instead of the more usual centroid of area as described above. * centre point of a

bounding box In geometry, the minimum or smallest bounding or enclosing box for a point set in dimensions is the box with the smallest measure (area, volume, or hypervolume in higher dimensions) within which all the points lie. When other kinds of measure a ...

completely enclosing the area. While relatively easy to determine, a centre point calculated using this method will generally also vary (relative to the shape of the landmass or region) depending on the orientation of the bounding box to the area under consideration. In this sense it is not a robust method. * finding the longitude that divides the region into two equal area parts to the east and west, and then similarly the latitude that divides the region into two equal area parts to the north and south. Like the bounding box approach described above this method would not generally locate precisely the same point if the same shaped region was oriented differently. As noted in a

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

document, "There is no generally accepted definition of geographic center, and no completely satisfactory method for determining it." In general, there is room for debate around various details such as whether or not to include islands and similarly, large bodies of water, how best to handle the curvature of the Earth (a more significant factor with larger regions) and closely related to that issue, which

map projection In cartography, map projection is the term used to describe a broad set of transformations employed to represent the two-dimensional curved surface of a globe on a plane. In a map projection, coordinates, often expressed as latitude and longitud ...

to use.

Notable geographical centres

Geographical centre of Earth The geographical center of Earth is the geometric center of all land surfaces on Earth. Geometrically defined it is the Centroid of all land surfaces within the two dimensions of the Geoid surface which approximates the Earth's outer shape. The ...

Axis mundi In astronomy, axis mundi is the Latin term for the axis of Earth between the celestial poles. In a geocentric coordinate system, this is the axis of rotation of the celestial sphere. Consequently, in ancient Greco-Roman astronomy, the '' ...

Omphalos of Delphi The Omphalos of Delphi is an ancient marble monument that was found at the archaeological site of Delphi, Greece. According to the Ancient Greek myths regarding the founding of the Delphic Oracle, the god Zeus, in his attempt to locate the cent ...

Geographic centres in Africa

* Geographic Centre of Uganda (Amolatar Monument)

Geographic centres in Asia

* Geographical midpoints of Asia, in

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

* Geographical centre of India **

Zero Mile Stone (Nagpur) Zero Mile Stone is a monument built by British during the Great Trigonometrical Survey of India in 1907 in Nagpur, Maharashtra. The Zero Mile Stone consists of a pillar made up of sandstone and another small stone representing the GTS Standard B ...

* Geographic center of Iran * Geographic centre of Sri Lanka * Geographical centre of the Korean Peninsula * Geographical centre of the Philippines * Geographical centre of the Russian Federation * Geographical centre of the Soviet Union *

Geographic center of Taiwan Geographic center of Taiwan is the geographical center, center point of Taiwan Island. It is located at ''Hutoushan'', "Tiger Head Mountain") in the township of Puli, Nantou, Puli in Nantou County, Taiwan. History The first Geographic Center ...

Geographic centres in Europe

Geographical midpoint of Europe The location of the geographical centre of Europe depends on the definition of the borders of Europe, mainly whether remote islands are included to define the extreme points of Europe, and on the method of calculating the final result. Thus, sev ...

* Geographical centre of Austria *

Geographic center of Belarus The geographical center of Belarus ( be, Геаграфічны цэнтр Беларусі) is at the geographical coordinates of latitude 53°31'44.54", longitude 28°02'41.90". It is located 70-km south-east of Minsk, a 6-km west of Marina ...

* Geographical centre of Belgium * Geographical centre of Estonia * Geographical centre of Germany **

Central Germany (geography) Central Germany (''Zentraldeutschland''/''Mitteldeutschland''), in geography, describes the areas surrounding the geographical centre of Germany. Hesse, Saxony-Anhalt and Thuringia are the only landlocked German states without an international ...

* Geographical centre of Hungary *

Geographical centre of Ireland The Geographical Centre of Ireland, according to an investigation and calculation carried out by the Official Irish Government Mapping Agency, Ordnance Survey Ireland (OSI) published on the official OSI website on 24 February 2022 is near the co ...

* Geographical centre of Lithuania *

Geographical centre of Norway The geographical centre of Norway has been identified as a spot in the Ogndalsfjella in the southeastern part of the municipality of Steinkjer in Trøndelag county, located at . A monument marking the significance of the spot was unveiled in a ce ...

* Geographical centre of Poland * Geographical center of Romania * Geographical centre of the Russian Federation * Geographical centre of Serbia * Geographical centre of Slovenia * Geographical centre of the Soviet Union *

Geographical center of Sweden The geographical center of Sweden is contested amongst at least four locations. Flataklocken The oldest and most famous geographical center of Sweden is Flataklocken, a spot next to Lake Munkby in Torpshammar, Medelpad at . The site was identifi ...

Geographical centre of Switzerland The geographical centre of Switzerland has the coordinates ( Swiss Grid: 660158/183641). It is located at Älggi-Alp in the municipality of Sachseln, Obwalden. The point is the centre of mass determined in 1988 by Swisstopo. As the point is di ...

Centre points of the United Kingdom There has long been debate over the exact location of the geographical centre of the United Kingdom, and its constituent countries, due to the complexity and method of the calculation, such as whether to include offshore islands, and the fact tha ...

** Geographical centre of Great Britain ** Centre points of counties of the United Kingdom ** Geographic centre of England **

Geographical centre of Scotland There is some debate as to the location of the geographical centre of Scotland. This is due to different methods of calculating the centre, and whether surrounding islands are included. Centre of gravity method In 2002, the Ordnance Survey calc ...

** Geographic centre of Wales

Geographic centres in North America

* Geographic center of North America * Geographic centre of Canada *

Geographic center of the United States The geographic center of the United States is a point approximately north of Belle Fourche, South Dakota at . It has been regarded as such by the U.S. National Geodetic Survey (NGS) since the additions of Alaska and Hawaii to the United States ...

List of geographic centers of the United States This is a list of geographic centers of each U.S. state and inhabited territory. The geographic center of the United States is northeast of Belle Fourche in Butte County, South Dakota , while that of the contiguous 48 states is near Lebanon in Smi ...

Geographic centres in Oceania

Centre points of Australia Centre points of Australia are those geographical locations that have been considered to be ''centre'' of Australia, as distinct from the extreme points of Australia. Finding the centre point John McDouall Stuart wrote "Sunday, 22 April 1860, ...

* Geographic centre of New Zealand

Geographic centres in South America

* Geographical Center of South America * Geographical Center of Colombia

References

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