The 180th meridian or antimeridian is the meridian 180° both east and west of the Prime Meridian, with which it forms a great circle dividing the earth into the Western and Eastern Hemispheres. It is common to both east longitude and west longitude. It mostly passes through the open waters of the Pacific Ocean, but passes across land in Russia, Fiji and Antarctica. This meridian is used as the basis for the International Date Line, but the latter deviates from it to maintain date consistency within the territories of Russia, the United States, Kiribati, Fiji and New Zealand.
|Country, territory or sea||Notes|
|Russia||Chukotka Autonomous Okrug — Wrangel Island|
|Russia||Chukotka Autonomous Okrug|
|Amchitka Pass||Passing just east of Semisopochnoi Island, Alaska, United States (at )|
|Pacific Ocean||Passing just east of Nukulaelae atoll, Tuvalu (at )|
Passing just west of the island of Cikobia, Fiji (at )
|Fiji||Islands of Vanua Levu, Rabi, and Taveuni|
|Pacific Ocean||Passing just east of the island of Moala, Fiji (at )|
Passing just west of the island of Totoya, Fiji (at )
Passing just east of the island of Matuku, Fiji (at )
|Antarctica||Ross Dependency, claimed by New Zealand|
The meridian also passes between (but not particularly close to):
The only place where roads cross this meridian, and where there are buildings very close to it, is in Fiji.
Many geographic software libraries or data formats project the world to a rectangle; very often this rectangle is split exactly at the 180th meridian. This often makes it non-trivial to do simple tasks (like representing an area, or a line) over the 180th meridian. Some examples:
The 1948 Pacific typhoon season is an event in the annual cycle of tropical cyclone formation, in which tropical cyclones form in the western Pacific Ocean. The season runs throughout 1948, though most tropical cyclones typically develop between May and October. The scope of this article is limited to the Pacific Ocean to the north of the equator between 100°E and 180th meridian. Within the northwestern Pacific Ocean, there are two separate agencies that assign names to tropical cyclones which can often result in a cyclone having two names. The Japan Meteorological Agency (JMA) will name a tropical cyclone should it be judged to have 10-minute sustained wind speeds of at least 65 km/h (40 mph) anywhere in the basin, whilst the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) assigns names to tropical cyclones which move into or form as a tropical depression in their area of responsibility located between 135°E and 115°E and between 5°N–25°N regardless of whether or not a tropical cyclone has already been given a name by the JMA. Tropical depressions that are monitored by the United States' Joint Typhoon Warning Center (JTWC) are given a number with a "W" suffix.2019 Pacific typhoon season
The 2019 Pacific typhoon season is an ongoing event in the annual cycle of tropical cyclone formation, in which tropical cyclones form in the western Pacific Ocean. The season runs throughout 2019, though most tropical cyclones typically develop between May and October. The season's first named storm, Pabuk, developed on January 1, becoming the earliest-forming tropical storm of the western Pacific Ocean on record, breaking the previous record held by Typhoon Alice in 1979. The season's first typhoon, Wutip, reached typhoon status on February 20. Wutip further intensified into a super typhoon on February 23, becoming the strongest February typhoon on record, and the strongest tropical cyclone recorded in February in the Northern Hemisphere.
The scope of this article is limited to the Pacific Ocean to the north of the equator between 100°E and 180th meridian. Within the northwestern Pacific Ocean, there are two separate agencies that assign names to tropical cyclones which can often result in a cyclone having two names. The Japan Meteorological Agency (JMA) will name a tropical cyclone should it be judged to have 10-minute sustained wind speeds of at least 65 km/h (40 mph) anywhere in the basin, whilst the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) assigns names to tropical cyclones which move into or form as a tropical depression in their area of responsibility located between 135°E and 115°E and between 5°N–25°N regardless of whether or not a tropical cyclone has already been given a name by the JMA. Tropical depressions that are monitored by the United States' Joint Typhoon Warning Center (JTWC) are given a number with a "W" suffix.45×90 points
The 45×90 points are the four points on earth which are halfway between the geographical poles, the equator, the Prime Meridian, and the 180th meridian.90th meridian east
The meridian 90° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole.
It is the border between two tropical cyclone basins: the Australian region, and the Southwest Indian Ocean basin.The Ninety East Ridge is named after the meridian.
The 90th meridian east forms a great circle with the 90th meridian west.
This meridian is halfway between the Prime meridian and the 180th meridian and the center of the Eastern Hemisphere is on this meridian.90th meridian west
The meridian 90° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, North America, the Gulf of Mexico, Central America, the Pacific Ocean, the Southern Ocean, and Antarctica to the South Pole.
In Antarctica, the meridian defines the western limit of Chile's territorial claim. The land further west is not claimed by any nation.
The 90th meridian west forms a great circle with the 90th meridian east, located midway between the Prime meridian and the 180th meridian; thus the center of the Western Hemisphere is on this meridian.Amchitka Pass
Amchitka Pass is a strait in Alaska, United States. It is located in the Aleutian Islands on the 180th meridian, between the Rat Islands group to the west and the Delarof Islands to the east. Amchitka Pass has a least width of 50 miles (80.5 km) and depths of 249 feet (76 meters) to over 6,000 feet (1,829 meters). The islands on both sides of the pass should be cleared by at least 5 miles (8 km). Heavy tide rips have been observed off the east end of Amchitka Island. The pass is dangerous in heavy weather, particularly for small and medium craft; currents appear erratic in direction and velocities may be strong. This may account for reports of very large seas and strong tide rips.Attu Station, Alaska
Attu Station is a census-designated place (CDP) located on Attu Island in the Aleutians West Census Area in the U.S. state of Alaska. The population was 21 at the 2010 census, consisting entirely of coast guard personnel who resided and worked at Casco Cove Coast Guard Station, but left the island when the station was closed in August 2010, leaving it uninhabited. LORAN Station Attu had provided a navigational signal for mariners of the North Pacific since the 1970s.Although often considered the westernmost place in the United States due to its location relative to the rest of the country, Attu Station is actually one of the easternmost points in the United States, located at 52°50′47″N 173°11′10″E, on the opposite side of the 180th meridian from the rest of the United States. (See Extreme Points.)Cape Wrangell
Cape Wrangell is considered to be the westernmost point of Alaska and all of the United States by direction of travel. It is located on Attu Island, which is situated in the Near Islands. Following this definition of westernmost, an alternative westernmost point would be located on the tiny (ca. 200m diameter) Peaked Island, just off the coast to the west, but because both sit west of the 180th meridian, these two are at times viewed as the easternmost points of the United States.Chukotka Autonomous Okrug
Chukotka Autonomous Okrug (Russian: Чуко́тский автоно́мный о́круг, tr. Chukotsky avtonomny okrug, IPA: [tɕʊˈkotskʲɪj ɐftɐˈnomnɨj ˈokrʊk]; Chukot: Чукоткакэн автономныкэн округ, Chukotkaken avtonomnyken okrug, IPA: [tɕukotˈkaken aβtonomˈnəken ˈokɹuɣ]) or Chukotka (Чуко́тка) is a federal subject (an autonomous okrug) of Russia. It is geographically located in the Far East region of the country, and is administratively part of the Far Eastern Federal District. Chukotka is the 2nd-least-populated federal subject at 50,526 (2010) and the least densely populated.Anadyr is the largest town and the capital of Chukotka, and the easternmost settlement to have town status in Russia.
Chukotka is home to Elgygytgyn Lake, an impact crater lake, and the village of Uelen, the easternmost settlement in Russia and the closest substantial settlement to the United States. The autonomous okrug's surface area is 737,700 square kilometers (284,800 sq mi), about 6% larger than the U.S. state of Texas, and is the 7th-largest Russian federal subject. The region is the most northeasterly region of Russia, and since the Alaska Purchase has been the only part of Russia lying partially in the Western Hemisphere (east of the 180th meridian). Chukotka shares a border with the Sakha Republic to the west, Magadan Oblast to the south-west, and Kamchatka Krai to the south.
Chukotka is primarily populated by ethnic Russians, Chukchis, and other indigenous peoples. It is the only autonomous okrug in Russia that is not included in, or subordinate to, another federal subject, having separated from Magadan Oblast in 1993.Hemispheres of Earth
In geography and cartography, the hemispheres of Earth refer to any division of the globe into two hemispheres (from Ancient Greek ἡμισφαίριον hēmisphairion, meaning "half of a sphere").
The most common such divisions are by latitudinal or longitudinal markers:
Northern Hemisphere, the half that lies north of the Equator
Southern Hemisphere, the half that lies south of the Equator
Eastern Hemisphere, the half that lies east of the prime meridian and west of the 180th meridian
Western Hemisphere, the half that lies west of the prime meridian and east of the 180th meridianThe East–West division can also be seen in a cultural sense, as a division into two cultural hemispheres.
However, other schemes have sought to divide the planet in a way that maximizes the preponderance of one geographic feature or another in each division:
Land–Water Land Hemisphere, the hemisphere on Earth containing the largest possible area of land
Water Hemisphere, the hemisphere on Earth containing the largest area of water
The Earth may also be split into hemispheres of day and night by the terrestrial terminator.IERS Reference Meridian
The IERS Reference Meridian (IRM), also called the International Reference Meridian, is the prime meridian (0° longitude) maintained by the International Earth Rotation and Reference Systems Service (IERS). It passes about 5.3 arcseconds east of George Biddell Airy's 1851 transit circle or 102 metres (335 ft) at the latitude of the Royal Observatory, Greenwich. It is also the reference meridian of the Global Positioning System (GPS) operated by the United States Department of Defense, and of WGS84 and its two formal versions, the ideal International Terrestrial Reference System (ITRS) and its realization, the International Terrestrial Reference Frame (ITRF).List of countries by easternmost point
This is a list of countries by easternmost point on land (dependent territories included). A selection of dependent territories are listed in italics and are not ranked.
The order does not always reflect the proximity of the country's territory to the 180th meridian. In such a case there would be three both the very westernmost and the very easternmost countries or territories, Russia, Fiji, and Antarctica, as the 180th meridian passes through them on land. Instead for the number of countries, namely Russia, New Zealand, Fiji, the United States, and Kiribati, which have territory on both sides of the 180th meridian, the given easternmost point of the country is the easternmost point in the direction of travel. The United States and Kiribati have most of their territory east of the 180th meridian, in the Western Hemisphere, so they are considered to belong to the westernmost countries with their territory stretching as far to the west as beyond the 180th meridian into the Eastern Hemisphere. Conversely, Russia, New Zealand, and Fiji have most of their territory west of the 180th meridian, in the Eastern Hemisphere, so they are considered to belong to the easternmost countries with their territory stretching as far to the east as beyond the 180th meridian into the Western Hemisphere.List of countries by westernmost point
This is a list of countries by westernmost point on land (dependent territories included). A selection of dependent territories are listed in italics and are not ranked.
There are five countries with territory on both sides of the 180th meridian, and thus can be said to be both the westernmost and easternmost countries: Russia, New Zealand, Fiji, United States, and Kiribati (as well as Antarctica). Russia, New Zealand, and Fiji have most of their territories west of the 180th meridian, in the Eastern Hemisphere, so they are considered in this article to belong to the easternmost countries with their territory stretching east beyond the 180th meridian into the Western Hemisphere. Conversely, the United States and Kiribati have most of their territories east of the 180th meridian, into the Western Hemisphere, so they are considered to belong to the westernmost countries, with their territory stretching west beyond the 180th meridian into the Eastern Hemisphere.Pacific typhoon climatology
The following is a list of Pacific typhoon seasons. The seasons are limited to the north of the equator between the 100th meridian east and the 180th meridian.Prime meridian
A prime meridian is a meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great circle. This great circle divides a spheroid, e.g., Earth, into two hemispheres. If one uses directions of East and West from a defined prime meridian, then they can be called the Eastern Hemisphere and the Western Hemisphere.
A prime meridian is ultimately arbitrary, unlike an equator, which is determined by the axis of rotation—and various conventions have been used or advocated in different regions and throughout history. The most widely used modern meridian is the IERS Reference Meridian. It is derived but deviates slightly from the Greenwich Meridian, which was selected as an international standard in 1884.Semisopochnoi Island
Semisopochnoi Island or Unyak Island (obsolete Russian: Семисопочной, modern Russian: Семисопочный Semisopochny – "having seven hills"; Aleut: Unyax) is part of the Rat Islands group in the western Aleutian Islands of Alaska. The island is uninhabited and provides an important nesting area for maritime birds. The island is of volcanic origin, containing several volcanoes including Mount Cerberus. It has a land area of 85.558 square miles (221.59 km2), measuring 18 kilometres (11 mi) in length and 20 kilometres (12 mi) in width.
At 179°46' East (+179.7667) (in the Eastern Hemisphere), the easternmost tip of Semisopochnoi is, by longitude, the easternmost land location in the United States and North America. Semisopochnoi sits only 14 minutes (0.2333 degrees) west of the 180th meridian.Solar eclipse of January 12, 1823
A partial solar eclipse occurred on January 22, 1823 during summer. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A partial solar eclipse occurs in the polar regions of the Earth when the center of the Moon's shadow misses the Earth.
It was one of four partial eclipses that took place that year, two within the space of two months each, the next one was on February 11 and covered the Northern Hemisphere. It was the three of last of solar saros 109, the next two were on January 22, 1841 and February 5, 1859.Universal polar stereographic coordinate system
The universal polar stereographic (UPS) coordinate system is used in conjunction with the universal transverse Mercator (UTM) coordinate system to locate positions on the surface of the earth. Like the UTM coordinate system, the UPS coordinate system uses a metric-based cartesian grid laid out on a conformally projected surface. UPS covers the Earth's polar regions, specifically the areas north of 84°N and south of 80°S, which are not covered by the UTM grids, plus an additional 30 minutes of latitude extending into UTM grid to provide some overlap between the two systems.
In the polar regions, directions can become complicated, with all geographic north–south lines converging at the poles. The difference between UPS grid north and true north can therefore be anything up to 180°—in some places, grid north is true south, and vice versa. UPS grid north is arbitrarily defined as being along the prime meridian in the Antarctic and the 180th meridian in the Arctic; thus, east and west on the grids when moving directly away from the pole are along the 90°E and 90°W meridians respectively.Western Hemisphere
The Western Hemisphere is a geographical term for the half of Earth which lies west of the prime meridian (which crosses Greenwich, London, United Kingdom) and east of the antimeridian. The other half is called the Eastern Hemisphere.
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