Height Reference Systems

• Introduction
• The German height reference system
• The European height reference system 
• Geoid and Gravity field modelling 

The European height reference system 

The national height reference systems of the European countries are each tied to different reference points (tide gauges). Due to this fact and also as a result of the differences in the theoretical definition of heights, the reference heights generally differ from each other by several dm, in extreme cases even up to 2 m.

National reference tide gauges in Europe and differences to EVRF2007 in cm (click to enlarge)

Therefore, for the purpose of realizing a uniform height system throughout Europe the UELN (United European Levelling Network) was established as an unification of the levelling networks of European countries. Presently, the 1^st order levelling networks of 26 European countries are contained in the UELN. The Data and Analysis Centre of the UELN is located at BKG.

United European Levelling Network (click to enlarge)

The results of the UELN adjustment of 1998 were handed over to the participating countries at beginning of 1999. One year later this solution was used as first realization of the EVRS and got the name EVRF2000.

After nearly 10 years a lot of national leveling networks had been replaced by new measurements. A new adjustment was performed which differs apart from the data mainly in the datum definition and the applied tidal system from EVRF2000. At the EUREF symposium 2007 in Brussels the EVRF2007 was adopted as new realization of EVRS

Detailed information about the European Vertical Reference System are available at special websites - EVRS.

In the Information System for European Coordinate Reference Systems CRS-EU are contained, besides a standardized description of the height systems, also transformation parameters for the transformation of the different national systems into the pan-European system.