Geodetic Reference systems
A geodetic reference system defines a spatial coordinates system (origin and orientation of coordinate axes) for indicating spatial positions (location, height) and gravity of points. This definition also specifies the shape, size and spatial location of the reference area (usually a rotation ellipsoid), plus (where applicable) the corresponding physical parameters of the earth’s gravity field and a map projection.
European reference systems
In addition to the conventional national reference systems, there is a European reference system called ETRS89. The connection of national reference systems to global, terrestrial reference systems by means of geodetic measuring methods results in only a limited degree of accuracy. However, modern (local) reference systems, distinguish themselves by providing a precisely defined link to global systems, thus allowing absolute positioning within a centimetre.
Swiss reference systems
With national survey LV95 a global (CHTRS95) and a local (CH1903+) system were defined in Switzerland which have functioned as the official Swiss reference system since 2017. The latter replaces the old local reference system (CH1903), which formed the basis for surveying in Switzerland for more than a hundred years.
Swiss map projections
Since its introduction in 1903, the Swiss national Survey has used the uniform map projection “Swiss Grid”. There are currently no plans to switch to UTM projection, as cited within the framework of CHTRS95 and now in use in many countries.
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