Local Swiss reference frames
Local reference frames are adapted to the special requirements of a given region (e.g. Switzerland) and should therefore only be used in that particular region. The following local frames are used in the national survey.
LV95: National survey 1995
(in the renewed Swiss reference system CH1903+)
Three-dimensional static reference frame based on the same control points as CHTRFyyyy. LV95 has been the official reference frame for surveying since 2017.
LHN95: National vertical network 1995
(in the Swiss height reference system LHN95)
The potential-theoretically rigorous height reference frame of the national survey, LV95, is based on precise levelling data (from 1902 until today), with the orthometric heights from the geoid model, CHGeo2004. The height reference is the orthometric height of the fundamental point in Zimmerwald. As before, Switzerland’s official height reference frame is LN02. The height transformation from LN02 to LHN95 and the European height reference frame EVRF is guaranteed by swisstopo.
Old national survey
The old national survey is based on the following local reference frames.
LV03: National survey 1903
(in the old Swiss reference system CH1903)
Reference frame based on the triangulation 1st - 3rd order .These were established in 1903 and regularly renewed and updated. The official heights are determined from the reference frame, LN02. LV03 was Switzerland's official reference frame until 2016. In accordance with Article 53, paragraph 2, Geoinformation Ordinance, LV03 was valid until 31 December 2020 for geodata that are not defined as official reference data. The LV03 reference frame had a high level of local accuracy in the centimetre range. But it was only suitable to a limited extent for national absolute positioning due to the existing distortions (up to 1.6 metres). Direct coordinate transformation, LV95 <-> LV03, is guaranteed by «CHENxy06» dataset throughout Switzerland with an average precision of +/- 3 centimetres.
LN02: National precise levelling 1902
(in the old Swiss height reference system LN02)
The official reference frame for height based on the “Nivellement de Précision” by the Swiss Geodetic Commission (1864-1887) and the new observations and measurements of the national levelling network from 1902 until today, without taking gravity into account. The reference frame indicates a good level of internal accuracy, but there are distortions in the decimetre range. Only an approximate direct height transformation, LHN95 <-> LN02, is possible. Nonetheless, LN02 remains the official Swiss height reference frame. Height transformation from LN02 to LHN95 is guaranteed by swisstopo.
National Survey LV95
In the period from 1988 to 1995 the Federal Office of Topography swisstopo developed a national surveying system that is largely based on satellite measurement. LV95 replaces the 100-year-old national survey (LV03), based on triangulation. The fundamental point for LV95 is the geostation in Zimmerwald, near Bern.
National triangulation network LV03
The national triangulation network (LV03) was established in around 1900 and until 2016 formed the official basis for surveys in Switzerland. The fundamental point of this network is the old observatory in Bern (coordinates 600'000 m / 200'000 m).
National survey control network: re-measurement campaigns
Every six years, swisstopo re-measures the national survey control network. Thanks to these measurements it is possible to obtain more precise information regarding Switzerland’s tectonic stability. Almost all geodata (i.e. data with a spatial context) that are used in Switzerland are based on one of the national survey control (fixed point) networks. It is therefore all the more important to periodically re-measure these networks. State-of-the-art satellite measurement technology is used for this purpose.
Federal Office of Topography swisstopo
Seftigenstrasse 264
3084 Wabern