Geodesy

system to specify locations on Earth

thumb|150px|right|The equator (yellow line) at the December solstice. The direction of the Sun is to the left. thumb|upright=1.35|Countries and territories that are intersected by the equator (red) or the IERS Reference Meridian|Prime Meridian (blue), which intersect at "[[Null Island".]] The equator is the circle of latitude that divides Earth into the Northern and Southern Hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumference, halfway between the North and South Poles. The term can also be used for any other celestial body that is roughly spherical.

thumb|Map of the world published in Amsterdam in the 17th century

thumb|Earth model with circles of latitude in black and indications of the North Pole, [[Equator, and the northern and southern hemispheres.]] thumb|upright=0.9|right|Earth's Graticule (cartography)|graticule. The vertical lines from pole to pole are lines of constant [[longitude, or meridians. The circles parallel to the equator are lines of constant latitude, or parallels. The graticule shows the latitude and longitude of points on the surface. In this example meridians are spaced at 6° intervals and parallels at 4° intervals.]]

thumb|Earth with blue longitude lines and corresponding degrees. thumb|upright=0.9|A Geographic coordinate system|graticule on the [[Earth as a sphere or an ellipsoid. The lines from pole to pole are lines of constant longitude, or meridians. The circles parallel to the Equator are circles of constant latitude, or parallels. The graticule shows the latitude and longitude of points on the surface. In this example, meridians are spaced at 6° intervals and parallels at 4° intervals.]]

300px|thumb|upright=1|Simplified schematic of only the lunar portion of Earth's tides, showing (exaggerated) high tides at the sublunar point and its antipodal point|antipode for the hypothetical case of an ocean of constant depth without land, and on the assumption that Earth is not rotating; otherwise there is a lag angle. Solar tides not shown.|alt= right|thumb|Earth's rotation drags the position of the tidal bulge ahead of the position directly under the Moon showing the lag angle. thumb|In Maine (U.S.), low tide occurs roughly at moonrise and high tide with a high Moon, corresponding to t

average level for the surface of one or more of Earth's oceans

thumb|upright=1.35|A medieval depiction of the Ecumene (1482, Johannes Schnitzer, engraver), constructed after the coordinates in Ptolemy's Geography and using his second map projection. The translation into Latin and dissemination of Geography in Europe, in the beginning of the 15th century, marked the rebirth of scientific cartography, after more than a millennium of stagnation.

Geophysics () is a physical science concerned with the processes and properties of Earth and its surrounding space environment, studied using quantitative and observational methods. It focuses primarily on Earth’s shape and its gravitational, magnetic, and electromagnetic fields. It also studies internal structure, composition, and dynamics, and their surface expression in tectonics, volcanism, and rock formation. Geophysics also encompasses a broader Earth-system and planetary perspective, including the oceans, atmosphere, cryosphere, ionosphere, magnetosphere, as well as solar–terrestrial in

thumb|upright=1.05|A modern instrument for geodetic measurements using satellites

thumb|Río de la Plata estuary thumb|Mattole River estuary

thumb|A navigation system on an oil tanker Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another. The field of navigation includes four general categories: land navigation, marine navigation, aeronautic navigation, and space navigation. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks. All navigational techniques involve locating the navigator's position compared to known locations or patterns. Navigation, in a broader sense, can refer to a

right|thumb|The azimuth is the angle formed between a reference direction (in this example north) and a sightline|line from the observer to a point of interest projected on the same plane as the reference direction orthogonal to the [[zenith.]]

point of intersection of a celestial body’s surface and its rotational axis

thumb|upright=1.05|A climber taking the final few steps to the summit of Imja Tse (Island Peak) in [[Nepal, 2004]] thumb|View from the summit of Switzerland's highest peak, [[Monte Rosa]]

thumb|upright=1.5|Map of the undulation of the geoid in meters (based on the EGM96 gravity model and the [[WGS84 reference ellipsoid).]]

elevation of a location in reference to a historic mean sea level taken as a vertical datum

direction and intensity of gravity in every point of space

acquisition of information about an object or phenomenon without making physical contact with the object, especially the Earth

thumb|A direct-readout theodolite, manufactured in the Soviet Union in 1958 and used for topographic surveying

system of satellites that provide autonomous geo-spatial positioning with global coverage

instrument with a sealed tube of liquid, designed to indicate whether a surface is horizontal (level) or vertical (plumb)

representation of the surface of a sphere or ellipsoid onto a plane map

line of longitude, at which longitude is defined to be 0°

thumb|upright=1.3|Low altitude aerial photograph for use in photogrammetry. Location: Three Arch Bay, [[Laguna Beach, California.]] Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant imagery and other phenomena. thumb|Photogrammetry of the headquarters of Fazenda do Pinhal, São Carlos-SP, Brazil While the invention of the method is attributed to Aimé Laussedat, the term "photogrammetry" was coined by the

acceleration that the Earth imparts to objects on or near its surface

gravitationally curved trajectory Earth travels around the Sun

combined electronic theodolite and electronic distance meter; used in surveying and building construction

arc crossing all meridians of longitude at the same angle

thumb|right|345px|alt=Topography of the Moon measured from the Lunar Orbiter Laser Altimeter on the mission Lunar Reconnaissance Orbiter, referenced to a sphere of radius 1737.4 km|Topography of the Moon. thumb|Moon 360 animation in 4K resolution|4K

Geodynamics is a subfield of geophysics dealing with dynamics of the Earth. It applies physics, chemistry and mathematics to the understanding of how mantle convection leads to plate tectonics and geologic phenomena such as seafloor spreading, mountain building, volcanoes, earthquakes, or faulting. It also attempts to probe the internal activity by measuring magnetic fields, gravity, and seismic waves, as well as the mineralogy of rocks and their isotopic composition. Methods of geodynamics are also applied to exploration of other planets.

continuously computed dead reckoning

thumb|right|200px |A circle of radius compressed to an ellipse. thumb|right|200px |A sphere of radius compressed to an oblate ellipsoid of revolution.

cartographic coordinate system

thumb|upright|An Autograv CG-5 gravimeter being operated

thumb|upright=1.4|Vertical distance comparison

thumb|A surveyor's shed showing equipment used for geomatics

gravity experiment

ellipsoid that approximates the figure of the Earth

difference between the observed acceleration of a planet's gravity and a value predicted from a model

thumb|upright=1.5|Principles of geolocation using GPS

mathematical descriptions of Earth's complex shape

assertion that the Earth is (at least approximately) spherical

type of astronomical interferometry used in radio astronomy

meridian line running through the Paris Observatory in Paris, France

3D model of land elevation and features; for specific DSM or DTM use specific wikidata IDs

cause of tidal locking

3D software model or representation of the Earth or another world

geodetic reference system

astronomical instrument

experiment to determine the mean density of the Earth

formula for the great-circle distance between two points on a sphere

line of longitude west of the Greenwich Meridian

reference ellipsoid

global coordinate reference system

The Hermannskogel () is a hill in Döbling, the 19th district of Vienna. At 542 metres above sea level, it is the highest natural point of Vienna. It lies on the border to Lower Austria.

system of geographic grid references used in Great Britain

outward bulge around a planet's equator due to its rotation

ED50 ("European Datum 1950", EPSG:4230) is a geodetic datum which was defined after World War II for the international connection of geodetic networks.