European Vertical Reference System
The IAG Subcommission 1.3.a (IAG SC 1.3 Homepage) for Europe EUREF (EUREF Homepage) started in 1994 with its activities for development and establishment of European height systems. Several projects were initiated. The work base on an excellent cooperation between EUREF, National Mapping Agencies (NMA), Working Group VIII of CERCO (Comité Européen des Responsables de la Cartographie Officielle - now EuroGeographics) and the Technical Working Group (TWG) of EUREF.
In accordance with the Resolution No. 3 of the EUREF Symposium 1994 in Warsaw, the objective of the United European leveling Network (UELN) project is to establish an unified vertical datum for Europe at the one-decimeter level with simultaneous enlargement of UELN as far as possible to the Eastern European countries. The results of the adjustment with status of end 1998 were handed over to each participating country under the name UELN95/98. One year later at the EUREF symposium 2000 in Tromsø a first definition of the European Vertical Reference System (EVRS) was adopted. The realization on the base of the UELN95/98 solution got the name EVRF2000.
The European Vertical Reference Network (EUVN) was prepared in parallel to the UELN. It is an integrated network of GNSS, levelling and tide gauge observations as a static height reference. On the basis of UELN and EUVN it was possible to derive relations between the UELN datum Normaal Amsterdams Peil and the European national height datums.
In the meantime the importance of harmonization of the vertical reference of spatial coordinates increased on the one hand and the extension, density and topicality of the available data were improved on the other hand. Half of the participating countries provided new national leveling data to the UELN data centre after the release of the last solution EVRF2000. Therefore, a new realization of the EVRS was computed and published under the name EVRF2007.
In the "Conventions for the Definition and Realization of a European Vertical Reference System (EVRS)" – EVRS Conventions 2007 – the IAG Subcommision 1.3a EUREF passed a revised definition of EVRS.
At the EUREF symposium in Brussels (June 2008) Resolution No. 3 was adopted which proposes to the European Commission that EVRF2007 is adopted as the vertical reference for pan-European geo-information.