The components of a reference system include:

• A coordinates system with zero point, coordinate axes and measurement unit
• The type of map projection by means of which a given region can be optimally depicted on a map.

There are global as well as national reference systems. The most widely used global reference system is the World Geodetic System (WGS84), which comprises longitudes and latitudes. Many countries (including Switzerland) have defined their own national reference systems. The official Swiss reference system is called «CH1903+». The designation «CH1903+» refers to the reference system that was introduced in Switzerland in 1903 and was updated during the 1990s. Switzerland also has a reference system called «CHTRS95» (Swiss Terrestrial Reference System 1995) which is used for scientific purposes

Have you ever tried to flatten an orange peel in one piece? This is not possible without causing the peel to split apart. The same problem applies when attempting to depict the spherical earth on a flat surface like a map. With the aid of map projection, a specific region (e.g. a country) can be depicted on a map with a minimum of distortion. The method used in Switzerland is called conformal, oblique cylinder projection.  

Based on this method, a grid of rectangular intersecting lines (the coordinates network) is incorporated into the Swiss national maps. These lines facilitate the determination of coordinates on the maps.