A state plane coordinate system provides a common datum of reference for
horizontal control of all surveys in a large area, just as the geoid furnishes a single
datum for vertical control. It eliminates having individual surveys based on different
assumed coordinates, unrelated to those used in other adjacent work.
State plane coordinates are available for all control points in the National Spatial
Reference System and for many other control points as well. They are widely
used as the reference points for initiating surveys of all types, including those for
highway construction projects, property boundary delineation, and photogrammetric
mapping.