Geological mapping of the earth’s surface (e.g. information from outcrops, quarries, etc.) forms the main basis for the production of geological maps. Geological units are interpreted according to their composition, age and location and are depicted on a topographic map together with various graphic elements. swisstopo produces maps at scales of 1:25 000 (Geological Atlas for use as the basis for the prevention of natural hazards, protection of groundwater, construction projects, etc.) up to 1:500 000 (overview map of Switzerland for studying the geological structure of the country).

Field mapping is supported through the use of modern surveying methods such as the evaluation of aerial images and digital elevation models, and it is supplemented with other basic data from boreholes and geophysical surveys. Both digital datasets and 3D models of the underground can be derived from these maps.

Geological maps currently form the sole nationwide dataset relating to the structure of the underground in Switzerland. They form an essential basis for dealing with numerous relevant geological issues associated with natural hazards, the protection and use of groundwater, mining of raw materials, extraction of energy and realization of infrastructure projects.