geodézii

Geodesy is the science that studies the Earth's shape, its orientation in space, and its gravity field, with the goal of measuring and understanding the size, form, and position of points on and above the Earth's surface. It provides the mathematical and physical framework for defining coordinates, maps, and navigation systems.

Over the centuries geodesy evolved from measuring Earth's circumference and astronomical observations to the use of satellites and space geodesy. Early networks used triangulation and leveling; the 20th century introduced gravimetry for the geoid, while the latter half of the century saw satellite laser ranging, very-long-baseline interferometry, and GNSS, culminating in global reference frames.

Branches: geometrical/topographic geodesy focuses on the shape and dimensions of the Earth; physical geodesy studies the gravity field and the geoid; satellite geodesy uses space techniques to determine precise coordinates. Methods include ground-based triangulation and trilateration, leveling, gravimetry, GNSS positioning, VLBI, SLR, DORIS, altimeter/radar and laser ranging, and InSAR.

Reference frames and datums: a reference ellipsoid approximates the Earth's shape; the geoid represents mean sea level equipotential surface; datums define coordinate systems. Global frames include ITRF and WGS84; local datums support construction, land surveying, and hydrographic work.

Applications: geodesy underpins accurate mapping, navigation, surveying, land administration, construction, and scientific research into plate tectonics, sea-level change, and crustal dynamics.

Professional activity is coordinated by organizations such as the International Association of Geodesy (IAG) and national surveying institutes; education combines geodesy, geophysics, and geospatial information science.