<P> A ground track or ground trace is the path on the surface of the Earth directly below an aircraft or satellite . In the case of a satellite, it is the projection of the satellite's orbit onto the surface of the Earth (or whatever body the satellite is orbiting). </P> <P> A satellite ground track may be thought of as a path along the Earth's surface which traces the movement of an imaginary line between the satellite and the center of the Earth . In other words, the ground track is the set of points at which the satellite will pass directly overhead, or cross the zenith, in the frame of reference of a ground observer . </P>

What is the projection of a satellite's orbit onto the earth represented in a 2d map called