Traditionally there have been two general types of control surveys:
horizontal and vertical. Horizontal surveys generally establish geodetic latitudes
and geodetic longitudes (see Section 19.4) of stations over large areas. From these
values, plane rectangular coordinates, usually in a state plane or Universal Transverse
Mercator (UTM) coordinate system (see Chapter 20) can be computed. On
control surveys in smaller areas, plane rectangular coordinates may be determined
directly without obtaining geodetic latitudes and longitudes.