Höhenbezugsnetze

Höhenbezugsnetze, also known as vertical datum networks or height reference systems, are fundamental to geodetic surveying and mapping. They provide a consistent framework for measuring and referencing elevations or heights above a defined surface. Without a standardized datum, height measurements would be inconsistent and unusable for many applications.

The most common reference surface for height measurements is the mean sea level. However, defining mean sea level precisely across large geographical areas is complex due to factors like ocean currents, tides, and atmospheric pressure. Consequently, different countries and regions may establish their own national or local height datums based on historical tide gauge data or levelling networks.

In Germany, the primary height datum is the Normalhöhennull (NHN), which is derived from the levelling network established by the former Prussian Geodetic Institute. This network has been continuously extended and modernized to ensure its accuracy. Other countries utilize similar national vertical datums, such as the North American Vertical Datum of 1988 (NAVD 88) in the United States and Canada.

The establishment and maintenance of height reference networks involve precise levelling surveys, which are conducted using specialized instruments to measure differences in elevation between points. These networks are crucial for a wide range of applications, including infrastructure planning and construction, flood risk assessment, hydrological studies, and scientific research. The accuracy and stability of the height reference network are paramount for the reliability of all derived height information.