Lagealtitude

Lagealtitude is a term that appears in some German-language technical contexts to describe the vertical distance of an object from the local surface directly beneath it, at the object's current horizontal position. In this sense, it is a location-relative measure of height, distinct from absolute altitude above mean sea level. The concept is sometimes used interchangeably with height above terrain or height above ground, depending on the source.

Etymology and usage notes indicate that the word is a compound of Lage (German for location or position) and altitude (height). Because it is not a standardized term in English-language geodesy or aviation, its meaning can vary between documents. When encountered, lagealtitude is typically defined as the vertical separation between the object and the terrain at its current coordinates, rather than the height above a geoid or ellipsoid.

Measurement and calculation commonly rely on combining elevation data with position information. Absolute altitude (above sea level) is obtained from GNSS, barometric sensors, or other sources, while terrain elevation at the same coordinates is taken from digital elevation models or LiDAR data. Lagealtitude is then computed as the difference between absolute altitude and terrain elevation, though some workflows describe it directly as height above terrain.

Applications and considerations include drone navigation, autonomous vehicles, and geospatial analysis, where awareness of terrain-following height is important. Limitations arise from DEM accuracy, terrain variability, sensor drift, and datum differences. In many contexts, similar concepts are referred to as altitude above ground level (AGL) or height above terrain (HAT).

See also: elevation, altitude, AG L, AMSL, digital elevation model, height above terrain.