An Earth ellipsoid or Earth spheroid is a mathematical figure approximating the Earth's form, used as a reference frame for computations in geodesy, astronomy...

the Earth. A spheroid describing the figure of the Earth or other celestial body is called a reference ellipsoid. The reference ellipsoid for Earth is...

seven climes). The realization that the figure of the Earth is more accurately described as an ellipsoid dates to the 17th century, as described by Isaac Newton...

An ellipsoid is a surface that can be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation...

same volume as the ellipsoid (R3). All three values are about 6,371 kilometres (3,959 mi). Other ways to define and measure the Earth's radius involve the...

geodesics on an ellipsoid arose in connection with geodesy specifically with the solution of triangulation networks. The figure of the Earth is well approximated...

triad is also known as Earth ellipsoidal coordinates (not to be confused with ellipsoidal-harmonic coordinates or ellipsoidal coordinates). Longitude...

on the Earth. The ECEF that is used for the Global Positioning System (GPS) is the geocentric WGS 84, which currently includes its own ellipsoid definition...

"Universal Transverse Mercator WGS 84 Zone 16N") comprises a choice of Earth ellipsoid, horizontal datum, map projection (except in the geographic coordinate...

standards, also includes a choice of geodetic datum (including an Earth ellipsoid), as different datums will yield different latitude and longitude values...

ellipsoid to that point Q on the surrounding sphere (of radius a) which is the projection parallel to the Earth's axis of a point P on the ellipsoid at...

The gravity of Earth, denoted by g, is the net acceleration that is imparted to objects due to the combined effect of gravitation (from mass distribution...

Earth section paths are plane curves defined by the intersection of an earth ellipsoid and a plane (ellipsoid plane sections). Common examples include...

was a way to determine the figure of the Earth, whose crucial parameter was the flattening of the Earth ellipsoid. In the 18th century, in addition of its...

0.5 mm (0.020 in) on the Earth ellipsoid. Vincenty's goal was to express existing algorithms for geodesics on an ellipsoid in a form that minimized the...

precipitation, allowing components such as nitrogen to cycle. Earth is rounded into an ellipsoid with a circumference of about 40,000 km. It is the densest...

dimensions of the Earth ellipsoid axes were defined by logarithms in keeping with former calculation methods. The Bessel ellipsoid fits especially well...

several parts: a model for Earth's shape and dimensions, such as a reference ellipsoid or a geoid; an origin at which the ellipsoid/geoid is tied to a known...

in cartography and geodesy the Earth is often approximated by an oblate spheroid, known as the reference ellipsoid, instead of a sphere. The current...

deviations of the actual surface from the ellipsoid, including the tallest mountains and deepest oceanic trenches. Earth's rotation also affects the sea level...

determine a figure of the Earth. One or more measurements of meridian arcs can be used to infer the shape of the reference ellipsoid that best approximates...

been replaced as the "International ellipsoid" by the newer Lucerne ellipsoid (1967) and GRS 80 (1980). Earth ellipsoid Defense Mapping Agency: Geodesy for...

the mean Sun. Multiplying the value in rad/s by Earth's equatorial radius of 6,378,137 m (WGS84 ellipsoid) (factors of 2π radians needed by both cancel)...

is a public registry of geodetic datums, spatial reference systems, Earth ellipsoids, coordinate transformations and related units of measurement, originated...

Earth's circumference is the distance around Earth. Measured around the equator, it is 40,075.017 km (24,901.461 mi). Measured passing through the poles...

(Central Bureau of International Geodesy), and a series of global ellipsoids of the Earth were derived (e.g., Helmert 1906, Hayford 1910/ 1924). A unified...

gravity on Earth's surface by means of a mathematical model representing Earth. The most common model of a smoothed Earth is a rotating Earth ellipsoid of revolution...

surface of the Earth. Common abstractions for the surface between two geographic points are: Flat surface; Spherical surface; Ellipsoidal surface. All abstractions...

Later arc measurements aimed at determining the flattening of the Earth ellipsoid by measuring at different geographic latitudes. The first of these...

determined by methods of astrogeodesy and is chosen as ellipsoidal latitude and longitude at the Earth ellipsoid which is used to calculate the coordinates of...