(World Geodetic System 1984): Terrestrial Reference System at
ED (European Datum): Terrestrial Reference System at European
GPS (Global Positioning System): System formed by a constellation
of satellites dedicated to navigation and positioning. Receivers
GPS determine the position where they are. In their configuration
options it is possible to specify the datum (by default in WGS-84).
Official Map: Each country adopts a specific one. Datum is indicated
in its legend.
Nautical Chart: Map used for navigation, that represents the coast
and the seafloor. Datum is indicated in its legend.