ortometrinen

Ortometrinen refers to a specific type of height measurement used in geodesy and surveying. It represents the distance from a point on the Earth's surface to the geoid, which is the equipotential surface of the Earth's gravity field that best approximates mean sea level. This measurement is considered the "true" height above sea level because it directly accounts for the irregular gravitational pull across the Earth's surface.

In contrast to ellipsoidal height, which is measured from a reference ellipsoid (a simplified mathematical model of the Earth), ortometric height takes into account the undulations of the geoid. The difference between these two height types is known as the geoid undulation or geoid height. Therefore, ortometric height is calculated by subtracting the geoid height from the ellipsoidal height.

Ortometric heights are crucial for applications where a consistent reference for water flow, topographic analysis, or engineering projects is required. For instance, when designing canals or drainage systems, understanding the ortometric height of different locations is essential to ensure gravity-driven flow. While the geoid is a complex and not perfectly defined surface, methods such as gravimetric surveys and satellite altimetry are used to determine its shape and thus enable the calculation of ortometric heights. The precise determination of the geoid remains an ongoing area of research in geodesy.