Rhumb lineIn navigation, a rhumb line, rhumb (rʌm), 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. The effect of following a rhumb line course on the surface of a globe was first discussed by the Portuguese mathematician Pedro Nunes in 1537, in his Treatise in Defense of the Marine Chart, with further mathematical development by Thomas Harriot in the 1590s.
GlobeA globe is a spherical model of Earth, of some other celestial body, or of the celestial sphere. Globes serve purposes similar to maps, but unlike maps, they do not distort the surface that they portray except to scale it down. A model globe of Earth is called a terrestrial globe. A model globe of the celestial sphere is called a celestial globe. A globe shows details of its subject. A terrestrial globe shows landmasses and water bodies. It might show nations and major cities and the network of latitude and longitude lines.
Geographical zoneThe five main latitude regions of Earth's surface comprise geographical zones, divided by the major circles of latitude. The differences between them relate to climate. They are as follows: The North Frigid Zone, between the North Pole at 90° N and the Arctic Circle at 66°33′48.7" N, covers 4.12% of Earth's surface. The North Temperate Zone, between the Arctic Circle at 66°33′48.7" N and the Tropic of Cancer at 23°26'11.3" N, covers 25.99% of Earth's surface. The Torrid Zone, between the Tropic of Cancer at 23°26'11.
Geographic coordinate systemThe geographic coordinate system (GCS) is a spherical or geodetic coordinate system for measuring and communicating positions directly on the Earth as latitude and longitude. It is the simplest, oldest and most widely used of the various spatial reference systems that are in use, and forms the basis for most others. Although latitude and longitude form a coordinate tuple like a cartesian coordinate system, the geographic coordinate system is not cartesian because the measurements are angles and are not on a planar surface.
Mercator projectionThe Mercator projection (mərˈkeɪtər) is a cylindrical map projection presented by Flemish geographer and cartographer Gerardus Mercator in 1569. It became the standard map projection for navigation because it is unique in representing north as up and south as down everywhere while preserving local directions and shapes. The map is thereby conformal. As a side effect, the Mercator projection inflates the size of objects away from the equator. This inflation is very small near the equator but accelerates with increasing latitude to become infinite at the poles.
Tissot's indicatrixIn cartography, a Tissot's indicatrix (Tissot indicatrix, Tissot's ellipse, Tissot ellipse, ellipse of distortion) (plural: "Tissot's indicatrices") is a mathematical contrivance presented by French mathematician Nicolas Auguste Tissot in 1859 and 1871 in order to characterize local distortions due to map projection. It is the geometry that results from projecting a circle of infinitesimal radius from a curved geometric model, such as a globe, onto a map.
Geographical poleA geographical pole or geographic pole is either of the two points on Earth where its axis of rotation intersects its surface. The North Pole lies in the Arctic Ocean while the South Pole is in Antarctica. North and South poles are also defined for other planets or satellites in the Solar System, with a North pole being on the same side of the invariable plane as Earth's North pole. Relative to Earth's surface, the geographic poles move by a few metres over periods of a few years.
South PoleThe South Pole, also known as the Geographic South Pole, Terrestrial South Pole or 90th Parallel South, is the southernmost point on Earth and lies antipodally on the opposite side of Earth from the North Pole, at a distance of 12,430 miles (20,004 km) in all directions. It is one of the two points where Earth's axis of rotation intersects its surface. Situated on the continent of Antarctica, it is the site of the United States Amundsen–Scott South Pole Station, which was established in 1956 and has been permanently staffed since that year.
