A
position representation is the parameters used to express a position relative to a reference. Representing position in three dimensions is often done by a
Euclidean vector. However, when representing position relative to the
Earth it is often more convenient to represent vertical position as
altitude or depth, and to use some other parameters to represent
horizontal position. There are also several applications where only the horizontal position is of interest, this might e.g. be the case for ships and ground vehicles/cars.