The solution of all tasks of the official and unofficial surveying presupposes a spatial reference. It is created uniformly by the foundation surveying and put to all users at the disposal. The realization of the spatial reference presupposes coordinate references system, control stations and/or the satellite positioning service SAPOS® and official documentation.
Geometrical spatial reference data (3D, position and height) and physical gravity values must in uniform, geodetic reference systems, which are represented to so-called coordinate references system. Which hides itself in detail behind it, you can reread under this point.