Siegfried Map
The original surveys for the Dufour Map were used for the publication of the 1:25,000 / 1:50,000 Topographic Atlas of Switzerland (Siegfried Map), which was produced between 1870 and 1926 as a co-operation between the federal government and the cantons, based on two Federal Acts dating from 1868.
Federal Office of Topography swisstopo
Infodesk history
Seftigenstrasse 264
3084 Wabern
Seftigenstrasse 264
3084 Wabern