Represents the coordinate system for a GPS measurement identified by
x1: latitude in degrees
x2: longitude in degrees
x3: elevation in meters
This coordinate system models the earth as a sphere of a specific radius.
Represents the WGS 84 coordinate system for a GPS measurement identified by
x1: latitude in degrees
x2: longitude in degrees
x3: elevation in meters
WGS84 models the earth as an ellipse.