Geodätische

Geodätische is the German adjective related to geodesy, the science that studies the Earth's shape, its orientation in space, and its gravity field, as well as the methods used to measure and represent these properties. In English, the corresponding term is geodetic.

Geodetic concepts encompass reference surfaces such as the reference ellipsoid and the geoid, as well as geodetic datums that fix a coordinate system to the Earth. A geodetic datum defines the size and shape of the model Earth, plus its position relative to the Earth, enabling the assignment of precise geographic coordinates. Geodetic coordinates—latitude, longitude, and height—are used to specify positions with respect to a chosen datum.

Measurements are conducted through networks and techniques that build a stable frame of reference. Traditional methods include triangulation, trilateration, and precise leveling to determine horizontal and vertical positions. Modern practice relies heavily on global navigation satellite systems (GNSS), such as GPS, GLONASS, and Galileo, to provide accurate positioning anywhere on the globe. Permanent geodetic networks tie local measurements to a global or regional reference frame.

Geodetic datums and reference frames include systems like WGS84 (global), NAD83 (North American), and ETRS89 (Europe). The choice of datum affects mapping, surveying, and navigation results. Applications span cartography, land administration, construction, aviation, and GIS.

A geodetic line, or geodesic, is the shortest path between two points on a curved surface; on a sphere this is a great circle, while on an ellipsoid it is a more complex curve.