National Geodetic Survey (NGS)

The National Geodetic Survey (NGS) is the U.S. federal agency mandated with defining, maintaining, and providing access to the National Spatial Reference System (NSRS). The NSRS includes all geodetic coordinate information, such as latitude, longitude, height and gravity, plus the official location of the coastline of the United States and its territories.

NGS is part of the National Ocean Service (NOS), a line office of the National Oceanic and Atmospheric Administration (NOAA), under the U.S. Department of Commerce (DOC). While NOS, NOAA, and DOC have histories limited to the late 20th century, NGS is the oldest scientific agency of the U.S. government. President Thomas Jefferson, a land surveyor himself, was vital to this history. He was instrumental in the design of the Public Land Survey System, in 1784; in the commission for the expedition of Lewis and Clark and the Corps of Discovery, in 1804; and in the signing of an act of Congress on February 10, 1807, which created the Survey of the Coast. Almost 200 years later and after three name changes (Coast Survey, 1836; U.S. Coast and Geodetic Survey, 1878; and National Geodetic Survey, 1970), NGS continues to perform its initial function of providing the geodetic infrastructure of the nation, so all surveying, mapping, and remote-sensing activities will be consistent with one another, in the NSRS.

The NSRS is one component, specifically the foundation, of the greater National Spatial Data Infrastructure (NSDI), established by the U.S. Office of Management and Budget in 1993. The NSRS could be considered the “bottom layer” (“foundation”) of any GIS project. Every layer has geospatially positioned data. However, this implies that such positions are given in a datum. The NSRS contains the official horizontal and vertical datums used in the United States (specifically, NAD 83 and NAVD 88). By defining these datums and how they are accessed in practice as well as their relationship to other datums (historic, international, etc.), NGS provides GIS users with the ability to align their geospatial data in a consistent, scientifically defined reference frame.

In the execution of its mission, NGS relies heavily on collaborations and partnerships both nationally and internationally. From data flowing from U.S. Geological Survey (USGS) and National GeospatialIntelligence Agency (NGA) to the transfer of technology to the U.S. Army Corps of Engineers (USACE) and the Federal Emergency Management Agency (FEMA), NGS serves as the foundation of all federal geospatial activities. In addition, NGS has collaborated with other countries on projects such as joint geoid modeling (Canada, Mexico, Caribbean), establishment of common datums (all of North America), and development of new spatial reference systems on other countries (Iraq, Romania, Benin). Last, many of the activities of NGS are linked through employee participation in various professional organizations (International Union of Geodesy and Geophysics (IUGG), International Federation of Surveyors (FIG), International Society for Photogrammetry and Remote Sensing (ISPRS), and International Hydrographic Organization (IHO), among others.