Coordinates are used for describing the exact position of a location on the ground, or on a map or plan. They normally take the form of figures that indicate the distance of the location concerned from the two coordinate axes. Coordinate axes are placed perpendicular to one another and run from south to north or from west to east. The point at which these axes intercept is referred to as the point of origin or «zero» point.

We can see coordinates on the national maps, for example, and on map apps on our smartphone. Coordinates are also used in the background in navigation devices so that we can find our destination.

If a location is to be described three-dimensionally, a third coordinate is required that indicates the height. Coordinates can also be indicated in the form of a combination of figures and letters, for example on a chess board, on a site or city map or in a spreadsheet.

As a rule, it is the official Swiss coordinates from the 1995 national survey (LV95) that are used in Switzerland. Other systems are in use throughout the world, for example the World Geodetic System (WGS84) with indications of longitude and latitude, which is a global reference system for geodetics and navigation.

The calculation of coordinates requires:

• a coordinates system with a zero point and coordinate axes, and
• a method by means of which the spherical earth can be optimally depicted on a flat map (referred to as map projection).

Once the coordinates have been defined, they can be put into practical application: on the ground they are marked in the form of control points. For each control point a measurement is made to calculate how far it is from the defined zero point or from the two coordinate axes. These two figures form the coordinates of this control point.