Glossary for Geospatial Science

State Plane Coordinate System or SPCS:  The State Plane Coordinate System (SPCS) defines map coordinates by zone for the United States.  Each zone has one central meridian and scale factor, which permits all USGS quadrangle maps in a zone to be mosaicked exactly.  Zones with north-south extent use the Transverse Mercator projection, while those with east-west extent use Lambert Conformal Conic.  (The panhandle of Alaska is the only exception, and uses Oblique Mercator).