Geodetikk

Geodetikk, or geodesy, is the science that studies the Earth's shape, its orientation in space, gravity field, and rotation. Its main goal is to provide precise positions on the Earth's surface and to monitor the planet's geometry and dynamics.

Central concepts include the reference ellipsoid, the geoid, and vertical and horizontal datums. A geodetic datum defines a coordinate reference system that translates measurements into a consistent frame. Global systems include WGS84 and ITRF; regional systems include ETRS89.

Measurement methods include terrestrial surveying methods (triangulation, trilateration, precise leveling), satellite-based techniques (GNSS such as GPS and GLONASS; satellite laser ranging; very-long-baseline interferometry), gravimetry and gravity measurements, altimetry, InSAR, and LiDAR. Data are integrated into geodetic networks and transformed between reference frames.

Applications span cartography, mapping, construction, infrastructure monitoring, navigation, land administration, and scientific research in geodynamics, seismology, and climate studies. Geodetikk supports accurate maps and positioning systems, informs risk assessments, and underpins scientific understanding of Earth's physical processes.

Geodetikk has a long history from early surveying to modern satellite geodesy. It is coordinated by international bodies such as the International Association of Geodesy (IAG) and, together with geophysics, the IUGG; institutions also work with IERS, IGS, and ITRF to maintain and improve global reference frames.