General information
The Swiss Confederation, in cooperation with the Cantons, is adopting a new coordinate reference frame and is thus planning to introduce new coordinates for the whole of Switzerland by 2016.
In order to make full use of the benefits of global navigation satellite system (GNSS) technologies such as GPS – especially the new generation of positioning services – and of data exchange with neighbouring countries, as well as to guarantee the integration of data into global systems and applications such as Google Earth or Google Maps, the reference frame which has served Switzerland for over 100 years has been renewed and connected to the European reference system.
The new datum is based on the national surveying of 1995 and is known as LV95. It is expected to replace the LV03 coordinates used in Switzerland today by 2016. Detailed information on the new Swiss reference frame can be found in the downloadable LV95 brochure.
The coordinates derived from the original national land survey of 1903, which are still valid today, show systematic deformations reaching a maximum of 2 to 3 m between Geneva and the Lower Engadine. At that time triangulation consisted only of angle measurement, while distances were derived from a few costly “base measurements”. This is the main reason for the systematic distortions in LV03.
- Deformations in the reference frame of 1903 which is currently in use (LV03: red grid), compared with the new, practically error-free, reference system of 1995 (LV95: grey grid).
In order to convert today's coordinates into the new system or, conversely, to be able to use highly accurate modern systems such as GPS to carry out surveys efficiently in the distorted LV03 reference frame, a transformation is required. At the end of 2006 the necessary official transformation data-set known as CHENyx06 was completed in cooperation with the Cantons. Switzerland was subdivided into a multitude of triangles, each having its own transformation parameters matched to local conditions: The national triangular transformation network (See FINELTRA manual, Chapter 2).
- CHENyx06 triangular transformation network
With the triangular transformation network and the transformation known as FINELTRA derived from it, GPS can be used efficiently in conjunction with the old, distorted, LV03 reference system. Moreover, the systematic deformations resulting from the first national survey of Switzerland in 1903 can be eliminated.
In order to estimate the accuracy of the transformation, the Cantons measured almost 45 000 check points. Analysis of the results showed that, on average over all the Cantons, geographical data in Switzerland can be transformed into the new, practically error-free, LV95 reference system or into global systems such as WGS84 (for example for GPS measurements) - and vice versa – with a mean accuracy of 2 cm.
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GeodesyLast updated: 09.01.2009
