Published on 8 January 2024

Historical Swiss reference systems

In the 19th century – before the introduction of reference system CH1903 for the Swiss national survey – other reference systems and map projections were used, especially for producing the Dufour and Siegfried maps. These parameters are still useful today for analysing historical data. In addition to these two main map series, other special reference systems were developed in the second half of the 19th century, but they will not be dealt with here.