National Geodetic Survey Positioning America for the Future geodesy.noaa.gov

NOAA Manages the National Spatial Reference System

NOAA’s National Geodetic Survey (NGS) defines, maintains, and provides access to the National Spatial Reference System (NSRS)— a consistent coordinate system that defines latitude, longitude, height, scale, gravity, orient- ation, and shoreline throughout the United States and is designed to meet our nation’s economic, social, and environmental needs. For 200 years, NGS and its predecessor agencies have collaborated with public and private n  organizations to establish reference stations at deflection of the vertical; precisely determined locations. Traditionally, n  models, tools, and guidelines; these locations have been identified by setting n  the official national shoreline; a survey mark—usually a brass, bronze, or aluminum disk. Locations might also be n  Global Navigation Satellite System identified by a deeply driven rod or a (GNSS) orbits; prominent object, such as a water tower or n  orientation, scale, and offset information church spire. More recently, NGS has fostered a relating NAD 83 to international terrestrial network of continuously operating reference reference systems; and stations (CORS) where each CORS includes a highly accurate receiver that continuously n  all necessary information to describe collects radio signals broadcast by Global how these values change over time. Navigation Satellite System (GNSS) satellites. The reference stations form a network used Components of the NSRS include: to accurately position other points of interest. Surveyors, mapping professionals, and others n geodetic positional coordinates (latitude, use the NSRS to ensure their positional coor- longitude, and ellipsoid and orthometric dinates are compatible with those determined heights) in the official U.S. datums, NSRS by others. In this way, when individuals create currently, the North American Datum of maps; mark property boundaries; and plan, 1983 (NAD 83) and the North American design, and build roads, bridges, and other Vertical Datum of 1988 (NAVD 88); structures, everything matches up. n geopotential ; NOAA Manages the Manages NOAA For more information, contact NGS: n acceleration of gravity; geodesy.noaa.gov

National Oceanic and Atmospheric Administration l National Geodetic Survey