Ortometrikus

Ortometrikus is a term used in geodesy and related fields to describe concepts and quantities related to orthometric heights, i.e., elevations measured with respect to the geoid or mean sea level. The adjective is the Hungarian form corresponding to the English orthometric.

In geodetic practice, orthometric height (h) is the distance measured along the local plumb line from the geoid (an idealized mean sea level surface) to a point on the Earth’s surface. This contrasts with ellipsoidal height (H), which is obtained from GNSS measurements and referenced to a mathematical reference ellipsoid. The two are related by the geoid undulation N through the standard equation H = h + N, or equivalently h = H − N, where N represents the separation between the ellipsoid and geoid at a given location.

Orthometric heights are widely used in civil engineering, construction, surveying, and cartography because they correspond to practical vertical elevations used for leveling and height measurements relative to sea level. The accuracy of ortometrikus quantities depends on the quality of the geoid model (the N values) and the precision of leveling or GNSS data.

Etymology and usage notes: the term derives from roots meaning correct or true measurement of height. In Hungarian technical literature, ortometrikus magasság or related phrases are commonly used to denote orthometric height and related vertical measurements.

See also: geodesy, orthometric height, geoid, ellipsoidal height, geoid model.