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NATIONAL SPATIAL REFERENCE SYSTEM
The National Spatial Reference System (NSRS) is the name given to all geodetic control contained
in the National
Geodetic Survey (NGS) Data Base. This includes:
A, B, First, Second and Third-Order horizontal and vertical control, Geoid models
such as GEOID 99,
precise GPS orbits and Continuously Operating Reference Stations (CORS), observed by NGS as well as data submitted by other
Federal, State, and
local agencies, academic institutions and the private sector
NATIONAL
OCEAN SERVICE