In geography, latitude is a coordinate that specifies the north–south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at the south pole to 90° at the north pole, with 0° at the Equator. Lines of constant latitude, or parallels, run east–west as circles parallel to the equator. Latitude and longitude are used together as a coordinate pair to specify a location on the surface of the Earth.
Longitude is a geographic coordinate that specifies the east–west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter lambda (λ). Meridians are imaginary semicircular lines running from pole to pole that connect points with the same longitude. The prime meridian defines 0° longitude; by convention the International Reference Meridian for the Earth passes near the Royal Observatory in Greenwich, south-east London on the island of Great Britain. Positive longitudes are east of the prime meridian, and negative ones are west.
The North Pole, also known as the Geographic North Pole, Terrestrial North Pole or 90th Parallel North, is the point in the Northern Hemisphere where the Earth's axis of rotation meets its surface. It is called the True North Pole to distinguish from the Magnetic North Pole.
North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. North is a noun, adjective, or adverb indicating direction or geography.
Gerardus Mercator was a Flemish geographer, cosmographer and cartographer. He is most renowned for creating the 1569 world map based on a new projection which represented sailing courses of constant bearing as straight lines—an innovation that is still employed in nautical charts.
The four cardinal directions, or cardinal points, are the four main compass directions: north, south, east, and west, commonly denoted by their initials N, S, E, and W respectively. Relative to north, the directions east, south, and west are at 90 degree intervals in the clockwise direction.
A projected coordinate system – also called a projected coordinate reference system, planar coordinate system, or grid reference system – is a type of spatial reference system that represents locations on Earth using Cartesian coordinates (x, y) on a planar surface created by a particular map projection. Each projected coordinate system, such as "Universal Transverse Mercator WGS 84 Zone 26N," is defined by a choice of map projection (with specific parameters), a choice of geodetic datum to bind the coordinate system to real locations on the earth, an origin point, and a choice of unit of measure. Hundreds of projected coordinate systems have been specified for various purposes in various regions.
A nautical chart or hydrographic chart is a graphic representation of a sea region or water body and adjacent coasts or banks. Depending on the scale of the chart, it may show depths of water (bathymetry) and heights of land (topography), natural features of the seabed, details of the coastline, navigational hazards, locations of natural and human-made aids to navigation, information on tides and currents, local details of the Earth's magnetic field, and human-made structures such as harbours, buildings, and bridges. Nautical charts are essential tools for marine navigation; many countries require vessels, especially commercial ships, to carry them. Nautical charting may take the form of charts printed on paper or computerized electronic navigational charts. Recent technologies have made available paper charts which are printed "on demand" with cartographic data that has been downloaded to the commercial printing company as recently as the night before printing. With each daily download, critical data such as Local Notices to Mariners are added to the on-demand chart files so that these charts are up to date at the time of printing.
In navigation, a rhumb line, rhumb, or loxodrome is an arc crossing all meridians of longitude at the same angle, that is, a path with constant bearing as measured relative to true north.
Sir John Ross was a Scottish Royal Navy officer and polar explorer. He was the uncle of Sir James Clark Ross, who explored the Arctic with him, and later led expeditions to Antarctica.
Inventio Fortunata, "Fortunate, or fortune-making, discovery", is a lost book, probably dating from the 14th century, containing a description of the North Pole as a magnetic island surrounded by a giant whirlpool and four continents. No direct extracts from the document have been discovered, but its influence on the Western idea of the geography of the Arctic region persisted for several centuries.
Great Ireland, also known as White Men's Land (Hvítramannaland), and in Latin similarly as Hibernia Major and Albania, was a land said by various Norsemen to be located near Vinland. In one report, in the Saga of Eric the Red, some skrælingar captured in Markland described the people in what was supposedly White Men's Land, to have been "dressed in white garments, uttered loud cries, bore long poles, and wore fringes." Another report identifies it with the Albani people, with "hair and skin as white as snow."
The NimrodExpedition of 1907–1909, otherwise known as the British Antarctic Expedition, was the first of three expeditions to the Antarctic led by Ernest Shackleton and his second time to the Continent. Its main target, among a range of geographical and scientific objectives, was to be first to reach the South Pole. This was not attained, but the expedition's southern march reached a Farthest South latitude of 88° 23' S, just 97.5 nautical miles from the pole. This was by far the longest southern polar journey to that date and a record convergence on either Pole. A separate group led by Welsh Australian geology professor Edgeworth David reached the estimated location of the South Magnetic Pole, and the expedition also achieved the first ascent of Mount Erebus, Antarctica's second highest volcano.
Sir James Clark Ross was a British Royal Navy officer and polar explorer known for his explorations of the Arctic, participating in two expeditions led by his uncle John Ross, and four led by William Edward Parry, and, in particular, for his own Antarctic expedition from 1839 to 1843.
The history of navigation, or the history of seafaring, is the art of directing vessels upon the open sea through the establishment of its position and course by means of traditional practice, geometry, astronomy, or special instruments. Many peoples have excelled as seafarers, prominent among them the Austronesians, the Harappans, the Phoenicians, the Iranians, the ancient Greeks, the Romans, the Arabs, the ancient Indians, the Norse, the Chinese, the Venetians, the Genoese, the Hanseatic Germans, the Portuguese, the Spanish, the English, the French, the Dutch, and the Danes.
Farthest South refers to the most southerly latitude reached by explorers before the first successful expedition to the South Pole in 1911.
Edward Wright was an English mathematician and cartographer noted for his book Certaine Errors in Navigation, which for the first time explained the mathematical basis of the Mercator projection by building on the works of Pedro Nunes, and set out a reference table giving the linear scale multiplication factor as a function of latitude, calculated for each minute of arc up to a latitude of 75°. This was in fact a table of values of the integral of the secant function, and was the essential step needed to make practical both the making and the navigational use of Mercator charts.
Arctic exploration is the physical exploration of the Arctic region of the Earth. It refers to the historical period during which mankind has explored the region north of the Arctic Circle. Historical records suggest that humankind have explored the northern extremes since 325 BC, when the ancient Greek sailor Pytheas reached a frozen sea while attempting to find a source of the metal tin. Dangerous oceans and poor weather conditions often fetter explorers attempting to reach polar regions, and journeying through these perils by sight, boat, and foot has proven difficult.
The Mercator world map of 1569 is titled Nova et Aucta Orbis Terrae Descriptio ad Usum Navigantium Emendate Accommodata. The title shows that Gerardus Mercator aimed to present contemporary knowledge of the geography of the world and at the same time 'correct' the chart to be more useful to sailors. This 'correction', whereby constant bearing sailing courses on the sphere are mapped to straight lines on the plane map, characterizes the Mercator projection. While the map's geography has been superseded by modern knowledge, its projection proved to be one of the most significant advances in the history of cartography, inspiring the 19th century map historian Adolf Nordenskiöld to write "The master of Rupelmonde stands unsurpassed in the history of cartography since the time of Ptolemy." The projection heralded a new era in the evolution of navigation maps and charts and it is still their basis.
Thomas Abernethy was a Scottish seafarer, gunner in the Royal Navy, and polar explorer. Because he was neither an officer nor a gentleman, he was little mentioned in the books written by the leaders of the expeditions he went on, but was praised in what was written. In 1857, he was awarded the Arctic Medal for his service as an able seaman on the 1824–25 voyage of HMS Hecla, the first of his five expeditions for which participants were eligible for the award. He was in parties that, for their time, reached the furthest north, the furthest south (twice), and the nearest to the South Magnetic Pole. In 1831, along with James Clark Ross's team of six, Abernethy was in the first party ever to reach the North Magnetic Pole.
![Part of the Carta marina
of 1539 by Olaus Magnus, depicting the location of magnetic north vaguely conceived as "Insula Magnetu[m]" (Latin for "Island of Magnets") off modern-day Murmansk. Starkad.jpg](http://upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Starkad.jpg/290px-Starkad.jpg)
