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{{Short description|U.S. federal surveying and mapping agency}}
[[File:DarienCTUSCoastAndGeodeticSurvey1965Marker11042007.jpg|thumb|right|250px|Closeup of a geodetic survey marker]]
{{Distinguish|Office of Coast Survey|National Ocean Service|United States Coast and Geodetic Survey|United States Geological Survey}}
{{Use American English|date=July 2022}}
{{Use mdy dates|date=January 2020}}


The '''National Geodetic Survey''' ('''NGS'''), formerly the '''United States Survey of the Coast''' (1807-1836), '''United States Coast Survey''' (1836-1878), and '''United States Coast and Geodetic Survey''' ('''USC&GS''') (1878-1970), is a [[United States federal government|United States federal agency]] that defines and manages a national coordinate system, providing the foundation for transportation and communication; mapping and charting; and a large number of applications of science and engineering. Since its foundation in its present form in 1970, it has been part of the [[National Oceanic and Atmospheric Administration]] (NOAA), of the [[United States Department of Commerce]].
The '''National Geodetic Survey''' ('''NGS''') is a [[List of federal agencies in the United States|United States federal agency]] based in [[Washington, D.C.]] that defines and manages a national coordinate system, providing the foundation for transportation and communication, mapping and charting, and a large number of science and engineering applications. Since its founding in 1970, it has been part of the [[National Oceanic and Atmospheric Administration]] (NOAA), a division within the [[United States Department of Commerce]].


[[File:DarienCTUSCoastAndGeodeticSurvey1965Marker11042007.jpg|thumb|upright=1|Closeup of a United States Coast and Geodetic Survey marker embedded in a large rock in front of the Noroton Volunteer Fire Department in [[Darien, Connecticut|Darien]], [[Connecticut]]]]
As the U.S. Coast Survey and U.S. Coast and Geodetic Survey, the agency operated a fleet of [[survey ship]]s, and from 1917 the Coast and Geodetic Survey was one of the uniformed services of the United States with its own corps of [[commissioned officer]]s. Upon the creation of the [[Environmental Science Services Administration]] (ESSA) in 1965, the commissioned corps was separated from the Survey to become the Environmental Science Services Administration Corps (or "ESSA Corps"). Upon the creation of NOAA in 1970, the ESSA Corps became the [[National Oceanic and Atmospheric Administration Commissioned Corps]] (or "NOAA Corps"), and the operation of ships was separated from the new National Geodetic Survey and transferred to the new [[NOAA ships and aircraft|NOAA fleet]]. Thus, the National Geodetic Survey{{'}}s ancestor organizations are also the ancestors of today{{'}}s NOAA Corps and are among the ancestors of today{{'}}s NOAA fleet.
[[File:Geodeticsurveypicwickenburg.jpg|thumb|upright=1|A survey marker in [[Wickenburg, Arizona|Wickenburg]], [[Arizona]]]]

[[File:East_Falls_Church_Station_survey_marker.jpg|thumb|upright=1|A metro survey marker at [[East Falls Church station]] in [[Arlington County, Virginia|Arlington County]], [[Virginia]]]]
==Purpose and function==
The National Geodetic Survey maintains the [http://geodesy.noaa.gov/INFO/OnePagers/NSRSOnePager.pdf National Spatial Reference System] (NSRS), "a consistent coordinate system that defines latitude, longitude, height, scale, gravity, and orientation throughout the United States."<ref>{{cite web|url=http://geodesy.noaa.gov/INFO/WhatWeDo.shtml|work=National Geodetic Survey Website|accessdate=27 May 2013|title="National Geodetic Survey - What We Do"}}</ref> NGS is responsible for defining the NSRS and its relationship with the [[International Terrestrial Reference Frame]]. NGS is a program office of the [[National Ocean Service]], a line office of [[NOAA]].

===Current projects===
* '''[[Continuously Operating Reference Station]] (CORS)''' GPS reference antennas to enable precise positioning
* '''[[Height Modernization]]'''
* '''[http://geodesy.noaa.gov/GRAV-D/ Gravity for the Redefinition of the Vertical Datum (GRAV-D)]''' An airborne gravimetric survey of the United States and its territories to measure the [[geoid]] and re-establish the height component of the NSRS
* '''[http://www.ngs.noaa.gov/INFO/OnePagers/AeroProgram.pdf Aeronautical Survey Program]''' Provides the precise locations of airports, runways and navgational aids in the United States to enable safe aerial navigation
* '''[http://www.ngs.noaa.gov/web/science_edu/ecosystems_climate/ Ecosystem and Climate Operations (ECO) Program]'''
* '''[http://www.ngs.noaa.gov/INFO/OnePagers/OPUSOnePager.pdf Online Positioning and User Service (OPUS)]''' An online tool for obtaining NSRS-referenced positions from geodetic GPS data
* '''[http://www.ngs.noaa.gov/INFO/OnePagers/VDatum.pdf Vertical Datum Transformation tool (Vdatum)]'''
* '''[http://www.ngs.noaa.gov/INFO/OnePagers/Orbit_Data.pdf GPS Orbits]'''
* '''[http://www.ngs.noaa.gov/INFO/OnePagers/Shoreline.pdf Shoreline mapping]'''
* '''[http://www.ngs.noaa.gov/INFO/OnePagers/StateAdvisor.pdf State geodetic advisor program]'''
* '''[http://www.ngs.noaa.gov/INFO/OnePagers/EmergencyResponseImageryOnePager.pdf Emergency response imagery]''' NGS rapidly provides aerial imagery of regions affected by natural disasters and other large-scale emergencies to enable emergency managers and members of the public to assess damage


==History==
==History==
{{See|United States Coast and Geodetic Survey}}
===Earliest years===
[[Image:US-NOAA-200thLogo.svg|right|thumb|230px|Logo celebrating the 200th anniversary of the founding of the United States Survey of the Coast.]]
The original predecessor agency of the NGS was the '''United States Survey of the Coast''', created by Congress in 1807 to conduct a "Survey of the Coast".<ref name="NOAA">[http://www.lib.noaa.gov/noaainfo/heritage/coastandgeodeticsurvey/index.html NOAA, ''Coast and Geodetic Survey Heritage'']</ref><ref name="timeline18071899">[http://www.history.noaa.gov/legacy/time1800.html noaa.gov NOAA History: NOAA Legacy Timeline 1807-1899]</ref> This organization, the [[United States Government]]{{'}}s first scientific agency,<ref name="timeline18071899"/> represented the Jefferson administration's interest in science and stimulation of international trade. The Jackson administration expanded and extended the Survey of the Coast{{'}}s scope and organization.<ref name="howe">{{cite book|title=What hath God Wrought, The Transformation of America, 1815–1848|last=Howe|first=Daniel W.|year=2007|publisher=Oxford University Press, Inc.|isbn=978-0-19-507894-7}}</ref>{{rp|468}}
Progress was slow and fitful during the first 25 years. Not until August 29, 1811, did [[Ferdinand Rudolph Hassler|F. R. Hassler]] sail for [[Europe]] to purchase the proper instruments. He remained in Europe during the [[War of 1812]], and then he returned to the [[United States]], arriving on August 16, 1815.


The National Geodetic Survey{{'}}s history and heritage are intertwined with those of other NOAA offices. It traces its history to the Survey of the Coast, which was formed in 1807 as the first scientific agency of the [[Federal government of the United States|United States federal government]]. It became the United States Coast Survey in 1836 and the United States Coast and Geodetic Survey in 1878, the latter name change reflecting the increasing role of [[geodesy]] in its work. Upon the creation of NOAA in 1970, the Coast and Geodetic Survey was abolished and its responsibilities were split among various agencies and offices of NOAA. The Coast and Geodetic Survey′s former geodetic responsibilities were placed under the new National Geodetic Survey in NOAA's National Ocean Survey (later renamed the [[National Ocean Service]]).
Hassler's plan was to employ triangulation to establish his system. Work began in the vicinity of [[New York City]] in 1816. The first baseline was measured and verified in 1817. A further [[Act of Congress]] in 1818 interfered with Hassler's work. The [[United States Army]] and [[United States Navy]] were placed in charge of the survey work. This generated a lull in activity which lasted from 1818 to 1832. The Survey of the Coast existed without a superintendent during the 14 years from 1818 to 1832.


In 2009, former [[NOAA Commissioned Officer Corps|National Oceanic and Atmospheric Administration Commissioned Officer Corps]] [[Commissioned officer|officer]] Juliana P. Blackwell was named Director of the National Geodetic Survey, becoming the first woman to head either NGS or any of its ancestor organizations.
Little work was carried out until another Federal law was enacted on July 10, 1832, that renewed the original law of 1807. Also in 1832, Hassler was reappointed as the Survey{{'}}s superintendent, and an Office of Weights of Measures, the ancestor of today{{'}}s [[National Institute of Standards and Technology]], was formed under the control of the Survey of the Coast.<ref name="timeline18071899"/> The Survey of the Coast resumed field work in April 1833.


==Purpose and function==
===Association with United States Navy===
The National Geodetic Survey is an office of NOAA's [[National Ocean Service]]. Its core function is to maintain the [[National Spatial Reference System]] (NSRS), "a consistent coordinate system that defines latitude, longitude, height, scale, gravity, and orientation throughout the United States".<ref name="What_We_Do">{{cite web |url=http://geodesy.noaa.gov/INFO/WhatWeDo.shtml |work=National Geodetic Survey Website |access-date=May 27, 2013 |title=National Geodetic Survey – What We Do}}</ref> NGS is responsible for defining the NSRS and its relationship with the [[International Terrestrial Reference System and Frame|International Terrestrial Reference Frame]] (ITRF). The NSRS enables precise and accessible knowledge of where things are in the United States and its territories.
The [[U.S. Department of the Navy]] was given the control of the Survey of the Coast from 1834 to 1836, but the [[U.S. Department of the Treasury]] resumed the administration of the Survey on March 26, 1836. The Survey of the Coast was renamed the '''United States Coast Survey''' in 1836.<ref name="timeline18071899"/>


The NSRS may be divided into its geometric and physical components. The official geodetic datum of the United States, [[North American Datum|NAD83]] defines the geometric relationship between points within the United States in three-dimensional space. The datum may be accessed via NGS's network of survey marks or through the [[Real-time kinematic|Continuously Operating Reference Station]] (CORS) network of [[Global Positioning System|GPS]] reference antennas. NGS is responsible for computing the relationship between NAD83 and the ITRF. The physical components of the NSRS are reflected in its height system, defined by the vertical datum [[North American Vertical Datum of 1988|NAVD88]]. This datum is a network of [[orthometric height]]s obtained through spirit [[Levelling|leveling]]. Because of the close relationship between height and Earth's gravity field, NGS also collects and curates terrestrial [[gravity]] measurements and develops regional models of the [[geoid]] (the level surface that best approximates sea level) and its slope, the [[Vertical deflection|deflection of the vertical]]. NGS is responsible for ensuring the accuracy of the NSRS over time, even as the [[North American Plate|North American plate]] rotates and deforms over time due to crustal strain, [[post-glacial rebound]], [[subsidence]], elastic deformation of the crust, and other geophysical phenomena.
[[Image:Sigsbee Sounding Machine-Blake.jpg|thumb|left|250px|Sigsbee Sounding Machine - invented by [[Charles Dwight Sigsbee]] and modified from Thomson Sounding Machine. Basic design of ocean sounding instruments stayed the same for the next 50 years. Here the sounding machine is used to set a Pillsbury current meter at a known depth. In: ''The Gulf Stream'', by John Elliott Pillsbury, 1891. Note caption on photo: "Sounding Machine And Current Meter In Place, Steamer ''Blake''"]]


NGS will release new datums in 2022.<ref>{{cite web |title=New Datums |url=https://geodesy.noaa.gov/datums/newdatums/index.shtml |website=National Geodetic Survey |access-date=March 21, 2017}}</ref> The North American Terrestrial Reference Frame of 2022 (NATRF2022) will supersede NAD83 in defining the geometric relationship between the North American plate and the ITRF.<ref name="geodesy.noaa.gov">{{cite web |author=US Department of Commerce, NOAA, National Geodetic Survey |title=Naming Conventions, New Datums |url=https://geodesy.noaa.gov/datums/newdatums/naming-convention.shtml |website=geodesy.noaa.gov |language=EN-US}}</ref> United States territories on the Pacific, Caribbean, and Mariana plates will have their own respective geodetic datums. The North American-Pacific Geopotential Datum of 2022 (NAPGD2022) will separately define the height system of the United States and its territories, replacing NAVD88.<ref name="geodesy.noaa.gov"/> It will use a geoid model accurate to 1 centimeter (0.4") to relate orthometric height to ellipsoidal height measured by GPS, eliminating the need for future leveling projects. This geoid model will be based on airborne and terrestrial gravity measurements collected by NGS's GRAV-D program as well as satellite-based gravity models derived from observations collected by [[GRACE and GRACE-FO|GRACE]], [[Gravity Field and Steady-State Ocean Circulation Explorer|GOCE]], and [[Satellite geodesy|satellite altimetry]] missions.<ref>{{cite web |author=US Department of Commerce, NOAA, National Geodetic Survey |title=xGEOID16 Evaluation Computation |url=https://beta.ngs.noaa.gov/GEOID/xGEOID16/ |website=beta.ngs.noaa.gov |language=EN-US}}</ref>
The Navy retained close connection with the hydrographic efforts of the Coast Survey under law requiring Survey ships to be commanded and crewed by naval officers and men when the Navy could provide such support.<ref>{{cite book |title=Report Of The Superintendent of the Coast And Geodetic Survey Showing The Progress Of The Survey During The Year 1874 |last=U.S. Coast and Geodetic Survey |first= |authorlink= |coauthors= |year=1877 |publisher=U.S. Government Printing Office |location=Washington, D.C. |isbn= |page=3 |pages= |url= |accessdate=2 March 2012}}</ref> Under this system many of the most famous names in hydrography for both the Survey and Navy of the period are linked. It was while attached to Coast Survey that Lieutenant Commander [[Charles Dwight Sigsbee]], USN, Assistant in the Coast Survey,<ref group=Note>The formal title given these officers in reports is for example: "Lieut. Commander John A. Howell, U.S.N., '''Assistant in the Coast Survey'''" with "Assistant" being a title for both high office and topographic survey management positions and ship's commanding officers.</ref> surveyed, developed his sounding machine and commanded the ship [[USC&GS George S. Blake|''Blake'']] during the first true bathymetric surveys in the [[Gulf of Mexico]]. Survey civilians were also assigned to the ships, along with famous scientist of the day, such as [[Alexander Agassiz]], for technical operations.<ref>{{cite web |url=http://celebrating200years.noaa.gov/rarebooks/blake/welcome.html |title=Three Cruises of the United States Coast and Geodetic Survey Steamer "Blake": In the Gulf of Mexico, in the Caribbean Sea, and Along the Atlantic Coast of the United States, from 1877 to 1880 |author=Alexander Agassiz |year=1888 |work= |publisher=Houghton, Mifflin and Company, Boston & New York |accessdate=2 March 2012}}</ref>


NGS provides a number of other public services.<ref name="What_We_Do"/> It maps changing shorelines in the United States and provides aerial imagery of regions affected by natural disasters, enabling rapid damage assessment by emergency managers and members of the public. The Online Positioning and User Service (OPUS) processes user-input GPS data and outputs position solutions within the NSRS. The agency offers other tools for conversion between datums.
That system remained effective until changed under appropriation law approved June 6, 1900 to the effect that beginning July 1, 1900 "all necessary employees to man and equip the vessels" were funded as opposed to the previous scheme using naval personnel. By prearrangement all naval personnel would remain with the ships until the first call at the home port where the transfer would be made with the Survey reimbursing Navy for pay after July 1 for those personnel.<ref>{{cite book |title=Report Of The Superintendent of the Coast And Geodetic Survey Showing The Progress Of Work From July 1, 1900 To June 30, 1901 |last=U.S. Coast and Geodetic Survey |first= |authorlink= |coauthors= |year=1901 |publisher=U.S. Government Printing Office |location=Washington, D.C. |isbn= |pages=15, 17, 109 |url= |accessdate=4 February 2012}}</ref>

===Growth years===

Professor [[Alexander Dallas Bache]] became superintendent of the U.S. Coast Survey after the death of Hassler in 1843.<ref name="timeline18071899"/> Earlier in his life, Bache had established the first magnetic observatory. During his years as superintendent, he expanded Coast Survey's work southward along the Atlantic coast into the [[Florida Keys]] and along the Pacific Coast. In 1845, he instituted the world{{'}}s first systematic oceanographic project for studying a specific phenomenon when he directed the Coast Survey to begin systematic studies of the [[Gulf Stream]] and its environs, including physical oceanography, [[Geology|geological]] oceanography, [[Biology|biological]] oceanography,and [[Chemistry|chemical]] oceanography. Bache{{'}}s initial orders for the Gulf Stream study served as a model for all subsequent integrated oceanographic cruises.<ref name="timeline18071899"/> Bache also instituted regular and systematic observations of the [[tide]]s and investigated [[Magnetism|magnetic]] forces and directions.

During the nineteenth century, the remit of the Survey was rather loosely drawn and it had no competitors in federally funded scientific research. Various Superintendents developed its work in fields as diverse as [[astronomy]], [[cartography]], [[meteorology]], [[geodesy]], [[geology]], [[geophysics]], [[hydrography]], [[navigation]], [[oceanography]], [[exploration]], [[pilotage]], [[tides]] and [[topography]]. The Survey published important articles by [[Charles Sanders Peirce]] on the design of experiments and on [[Peirce's criterion|a criterion]] for the statistical treatment of [[outlier]]s.<ref>
{{cite journal
|first=Charles Sanders
|last=Peirce
|authorlink=Charles Sanders Peirce
|title=Appendix No. 21. On the Theory of Errors of Observation
|journal=Report of the Superintendent of the United States [[Coast Survey]] Showing the Progress of the Survey During the Year 1870
|year=1870 [published 1873]
|pages=200–224
}}. NOAA [http://docs.lib.noaa.gov/rescue/cgs/001_pdf/CSC-0019.PDF#page=215 PDF Eprint] (goes to Report p. 200, PDF's p. 215). U.S. Coast and Geodetic Survey Annual Reports [http://docs.lib.noaa.gov/rescue/cgs/data_rescue_cgs_annual_reports.html links for years 1837–1965]. Reprinted in ''[[Charles Sanders Peirce bibliography#W|Writings of Charles S. Peirce]]'', v. 3, pp. 140–160.
</ref>
<ref>
[[Charles Sanders Peirce|Peirce, C. S.]] (1876 [published 1879]), "Appendix No. 14. Note on the Theory of the Economy of Research" in ''Report of the Superintendent of the United States [[Coast Survey]] Showing the Progress of the Survey for Fiscal Year Ending with June 1876'', pp.&nbsp;197–201, [http://docs.lib.noaa.gov/rescue/cgs/001_pdf/CSC-0025.PDF#page=222 NOAA PDF Eprint], goes to p. 197, PDF's page 222. Reprinted in ''[[Charles Sanders Peirce bibliography#CP|Collected Papers of Charles Sanders Peirce]]'', v. 7, paragraphs 139–157 and in ''[http://or.journal.informs.org/cgi/content/abstract/15/4/643 Operations Research]'' v. 15, n. 4, July–August 1967, pp. 643–648, [http://www.jstor.org/stable/168276 abstract at JSTOR] {{cite journal|last1=Peirce|first1=C. S.|title=Note on the Theory of the Economy of Research|journal=Operations Research|volume=15|pages=643|year=1967|doi=10.1287/opre.15.4.643|issue=4}}
</ref> For example, from 1836 until the establishment of the [[National Institute of Standards and Technology|National Bureau of Standards]] in 1901, the Survey was responsible for [[weights and measures]] throughout the United States.

The ''[http://www.nauticalcharts.noaa.gov/nsd/hcp.htm Coast Pilot]''<ref group=Note>The U.S. Coast Survey published its earliest version of the ''Coast Pilot'' as an appendix in the 1858 Coast Survey Report. Later, after the copyright to a private edition was sold to the United States in 1867 the Survey assumed the responsibility for regular publication.</ref> had long been lacking in current information. The Coast Survey had recognized that deficit but been hindered by lack of funding and risks associated with mooring vessels in deep waters or along dangerous coasts in order to collect the information. Congress specifically appropriated funding for such work in the 1875-1876 budget under which the 76 foot [http://www.history.noaa.gov/ships/ship6.html#drift schooner ''Drift''] was constructed and sent out under Acting Master Robert Platt, USN, Assistant Coast Survey, to the [[Gulf of Maine]] to anchor in depths of up to 140 fathoms (840 feet/256 meters) to measure currents.<ref>{{cite book |title=Report Of The Superintendent of the Coast And Geodetic Survey Showing The Progress Of The Work for the Fiscal Year Ending With June, 1877 |last=U.S. Coast and Geodetic Survey |first= |authorlink= |coauthors= |year=1877 |publisher=U.S. Government Printing Office |location=Washington, D.C. |isbn= |page=9 |pages= |url= |accessdate=2 March 2012}}</ref> The Survey's requirement led to early development of current measurement technology, particularly the [http://www.photolib.noaa.gov/htmls/ship4033.htm Pillsbury current meter] invented by [[John E. Pillsbury]], USN while on duty with the survey. It was in connection with intensive studies of the [[Gulf Stream]] that the ship [[USC&GS George S. Blake|''George S. Blake'']] became such a pioneer in oceanography that she is one of only two U.S. ships with her name inscribed in the façade of the [[Oceanographic Museum| Oceanographic Museum (Musée Océanographique)]], Monaco due to its being "the most innovative oceanographic vessel of the Nineteenth Century" with development of deep ocean exploration through introduction of steel cable for sounding, dredging and deep anchoring and data collection for the "first truly modern bathymetric map of a deep sea area."<ref Name=GSBNOAA>{{cite web |url=http://www.history.noaa.gov/ships/blake.html |title=''George S. Blake'' |author= |year=2006 |work=NOAA History: Coast and Geodetic Survey Ships |publisher=National Oceanic & Atmospheric Administration (NOAA), NOAA Central Library |accessdate=9 February 2012}}</ref>

On June 21, 1860, the greatest loss of life in a single incident in the history of NOAA and its ancestor agencies occurred when a commercial [[schooner]] collided with the Coast Survey [[steamer]] [[USCS Robert J. Walker (1844)|''Robert J. Walker'']] in the [[Atlantic Ocean]] off [[New Jersey]]. ''Robert J. Walker'' sank with the loss of 20 men.<ref>[http://www.history.noaa.gov/ships/ship22.html#walker NOAA History, A Science Odyssey: Tools of the Trade: Ships: Coast and Geodetic Survey Ships: Robert J. Walker]</ref><ref name="story">[http://www.nauticalcharts.noaa.gov/RobertJWalker/The%20Story%20of%20the%20Robert%20J.%20Walker.pdf noaa.gov The Story of the Coast Survey Steamer Robert J. Walker]</ref>

===American Civil War===
[[Image:Reconnaissance of the Mississippi River.jpg|thumb|right|Survey of the Mississippi River below Forts Jackson and St. Philip to prepare for the bombardment of the forts by Porters mortar fleet. Plan done by the U.S. Coast Survey.<ref>Official Records of the Union and Confederate Navies, Series I, Volume 18, p.362.</ref>]]

The outbreak of the [[American Civil War]] in April 1861 caused a dramatic shift in direction for the Coast Survey. All U.S. Army officers were withdrawn from the Survey, as were all but two U.S. Navy officers. Since most men of the Survey had [[Union (American Civil War)|Union]] sympathies, most stayed on with the Survey rather than resigning to serve the [[Confederate States of America]], and their work shifted in emphasis to support of the U.S. Navy and [[Union Army]]. Civilian Coast Surveyors were called upon to serve in the field and provide mapping, hydrographic, and engineering expertise for Union forces. One of the individuals who excelled at this work was [[Joseph Smith Harris]], who supported [[Rear Admiral (United States)|Rear Admiral]] [[David G. Farragut]] and his [[Western Gulf Blockading Squadron]] in the [[Battle of Forts Jackson and St. Philip]] in 1862; this survey work was particularly valuable to [[Commander (United States)|Commander]] [[David Dixon Porter]] and his [[Mortar (weapon)|mortar]] bombardment fleet. Coast Surveyors served in virtually all theaters of the war and were often in the front lines or in advance of the front lines carrying out mapping duties, and Coast Survey officers produced many of the coastal charts and interior maps used by Union forces throughout the war. Coast Surveyors supporting the Union Army were given assimilated military rank while attached to a specific command, but those supporting the U.S. Navy operated as civilians and ran the risk of being executed as [[Espionage|spies]] if captured by the Confederates while working in support of Union forces.<ref name="noaahistoryuscgs">[http://www.history.noaa.gov/legacy/corps.html NOAA History: NOAA Corps and the Coast and Geodetic Survey]</ref><ref name="timeline18071899"/>

===Later 19th century and early 20th century===
[[File:U.S. Coast and Geodetic Survey emblem.jpg|300px|thumb|right|The seal of the United States Coast and Geodetic Survey]]Army officers never returned to the Coast Survey, but after the war Navy officers did, and the Coast Survey resumed its peacetime duties. The acquisition of the [[Territory of Alaska]] in 1867 expanded its responsibilities, as did the progressive exploration, settlement, and enclosure of the [[continental United States]].<ref name="NOAA" /><ref name="noaahistoryuscgs"/> In 1871, Congress officially expanded the Coast Survey{{'}}s responsibilities to include geodetic surveys in the interior of the country,<ref name="NOAA" /><ref name="noaahistoryuscgs"/><ref name="timeline18071899"/> and one of its first major projects in the interior was to survey the [[39th parallel north|39th Parallel]] across the entire country. Between 1874 and 1877, the Coast Survey employed the [[naturalist]] and author [[John Muir]] as a guide and artist during the survey of the 39th Parallel in the [[Great Basin]] of [[Nevada]] and [[Utah]].<ref name="timeline18071899"/> To reflect its acquisition of the mission of surveying the U.S. interior and the growing role of [[geodesy]] in its operations, the U.S. Coast Survey was renamed the '''United States Coast and Geodetic Survey''' ('''USC&GS''') in 1878.<ref name="NOAA" /><ref name="noaahistoryuscgs"/><ref name="timeline18071899"/>

With the outbreak of the [[Spanish-American War]] in April 1898, the U.S. Navy again withdrew its officers from Coast and Geodetic Survey duty, and it never assigned them to duty with the Survey again. As a result of the war, which ended in August 1898, the United States took control of the [[Philippine Islands]] and [[Puerto Rico]], and surveying their waters became part of the Coast and Geodetic Survey's duties.<ref name="noaahistoryuscgs"/> The Survey opened a field office in [[Seattle, Washington|Seattle]], [[Washington (U.S. state)|Washington]] in 1899, to support survey ships operating in the [[Pacific Ocean]] as well as survey field expeditions in the [[western United States]]; this office eventually would become the modern [[National Oceanic and Atmospheric Administration]] Pacific Marine Center.<ref name="timeline18071899"/>

In 1901, the Office of Weights and Measures was split off from the Coast and Geodetic Survey to become the separate National Bureau of Standards. It became the [[National Institute of Standards and Technology]] in 1988.<ref name="timeline19001969">[http://www.history.noaa.gov/legacy/time1900_1.html noaa.gov NOAA History: NOAA Legacy Timeline 1900-1969]</ref>

===World War I===
Although some personnel aboard Coast and Geodetic Survey ship wore uniforms virtually identical to those of the U.S. Navy, the Survey operated as a completely civilian organization until after the United States entered [[World War I]] in April 1917. To avoid the dangerous situation Coast Survey personnel had faced during the American Civil War, when they could have been executed as spires if captured by the enemy, a new '''Coast and Geodetic Survey Corps''' was created on 22 May 1917, giving the Survey{{'}}s officers a [[Commissioned officer|commissioned]] status that protected them from treatment as spies if captured, as well as providing the [[United States armed forces]] with a ready source of officers skilled in surveying that could be rapidly assimilated for wartime support of the armed forces.<ref name="noaahistoryuscgs"/>

Over half of all Coast and Geodetic Survey Corps officers served in the U.S. Army, U.S. Navy, and U.S. Marine Corps during World War I, and Coast and Geodetic Survey personnel were active as artillery orienteering officers, as [[minelaying]] officers in the [[North Sea]] (where they supprted the laying of the [[North Sea Mine Barrage]]), as [[troop transport]] navigators, as [[Military intelligence|intelligence]] officers, and on the staff of [[General (United States)|General]] [[John Pershing|John "Black Jack" Pershing]].<ref name="noaahistoryuscgs"/>

===Interwar period===

During the period between the world wars, the Coast and Geodetic Survey returned to its peaceful scientific and surveying pursuits, including land surveying, sea floor charting, coastline mapping, [[geophysics]], and [[oceanography]].<ref name="noaahistoryuscgs"/> In 1923 and 1924, it began the use of [[Acoustics|acoustic]] sounding systems and developed radio acoustic ranging, which was the first marine [[navigation]] system in history that did not rely on a visual means of position determination. These developments led to the Survey{{'}}s 1924 discovery of the [[SOFAR channel|sound fixing and ranging (SOFAR) channel]] or deep sound channel (DSC) &ndash; a horizontal layer of water in the ocean at which depth the speed of sound is at its minimum &ndash; and to the development of [[Telemetry|telemetering]] radio [[sonobuoy]]s and and marine [[Seismology|seismic]] exploration techniques.<ref name="timeline19001969"/> The [[Air Commerce Act]], which went into effect on May 20, 1926, among other things directed that the [[Flight path|airways]] of the United States be charted for the first time and assigned this mission to the Coast and Geodetic Survey.<ref name="timeline19001969"/>

In 1933, the Coast and Geodetic Survey opened a ship base in [[Norfolk, Virginia|Norfolk]], [[Virginia]]. From 1934 to 1937, it organized surveying parties and field offices to employ over 10,000 people, including many unemployed [[engineer]]s, during the height of the [[Great Depression in the United States|Great Depression]].<ref name="timeline19001969"/>

===World War II===

When the United States entered [[World War II]] in December 1941, all of this work was suspended as the Survey dedicated its activities entirely to support of the war effort. Over half of the Coast and Geodetic Corps commissioned officers were transferred to either the U.S. Army, U.S. Navy, U.S. Marine Corps, or [[United States Army Air Forces]], while those who remained in the Coast and Geodetic Survey also operated in support of military and naval requirements. About half of the Survey{{'}}s civilian work force, slightly over 1,000 people, joined the armed services.<ref name="noaahistoryuscgs"/>

Officers and civilians of the Survey saw service in [[North African campaign|North Africa]], [[European Theater of World War II|Europe]], and the [[Pacific Theater of World War II|Pacific]] and in the defense of [[North America]] and its waters, serving as artillery surveyors, [[Hydrography|hydrographers]], [[Amphibious warfare|amphibious]] engineers, [[beachmaster]]s, instructors at service schools, and in a wide range of technical positions. Coast and Geodetic Survey personnel also worked as reconnaissance surveyors for a worldwide aeronautical charting effort, and a Coast and Geodetic Survey Corps officer was the first [[commanding officer]] of the Army Air Forces Aeronautical Chart Plant at [[St. Louis, Missouri|St. Louis]], [[Missouri]]. Coast and Geodetic Survey civilians who remained in the United States during the war produced over 100 million maps and charts for the [[Allies of World War II|Allied]] forces. Three Coast and Geodetic Survey officers and eleven members of the agency who had joined other services were killed during the war.<ref name="noaahistoryuscgs"/>

===Post-World War II===

Following World War II, the Coast and Geodetic Survey resumed its peacetime scientific and surveying efforts. In 1945 it adapted the British [[Royal Air Force]]{{'}}s [[Gee (navigation)|Gee]] [[radio navigation]] system to hydrographic surveying, ushering in a new era of marine electronic navigation. In 1948 in established the [[Pacific Tsunami Warning Center]] in [[Honolulu, Hawaii|Honolulu]] [[Hawaii]].<ref name="timeline19001969"/> The onset of the [[Cold War]] in the late 1940s led the Survey also to make a significant effort in support of defense requirements, such as conducting surveys for the [[Distant Early Warning Line]] and for [[rocket]] ranges, performing oceanographic work for the U.S. Navy, and monitoring [[Nuclear weapon|nuclear]] tests.<ref name="timeline19001969"/>

In 1955, the Coast and Geodetic Survey ship [[USC&GS Pioneer (OSS 31)|USC&GS ''Pioneer'' (OSS 31)]] conducted a survey in the Pacific Ocean off the [[United States West Coast]] towing a [[magnetometer]] invented by the [[Scripps Institute of Oceanography]]. The first such survey in history, it discovered [[magnetic striping]] on the seafloor, a key finding in the development of the theory of [[plate tectonics]].<ref name="timeline19001969"/>

The Coast and Geodetic Survey participated in the [[International Geophysical Year]] (IGY) of July 1, 1957, to December 31, 1958. During the IGY, 67 countries cooperate in a worldwide effort to collect, share, and study data on eleven [[Earth science]]s &ndash; [[Auroral light|aurora]] and [[airglow]], [[cosmic ray]]s, [[Earth's magnetic field|geomagnetism]], [[gravity]], [[ionosphere|ionospheric physics]], [[longitude]] and [[latitude]] determinations for precision mapping, [[meteorology]], [[oceanography]], [[seismology]], and [[Space weather|solar activity]].<ref name="timeline19001969"/>

In 1959, the Coast and Geodetic Survey{{'}}s charter was extended to give it the responsibility for U.S. Government oceanographic studies worldwide.<ref name="noaahistoryuscgs"/> In 1963, it became the first U.S. Government scientific agency to take part in an international cooperative oceanographic/[[Meteorology|meteorological]] project when the survey ship [[USC&GS Explorer (OSS 28)|USC&GS ''Explorer'' (OSS 28)]] made a scientific cruise in support of the [[EQUALANT I]] and [[EQUALANT II]] subprojects of the [[International Cooperative Investigations of the Tropical Atlantic]] (ICITA) project.<ref>[http://www.history.noaa.gov/ships/explorer2.html NOAA History, A Science Odyssey: Tools of the Trade: Ships: Coast and Geodetic Survey Ships: Explorer]</ref><ref>[http://www.st.nmfs.noaa.gov/copepod/data/equalant/index.html nmfs.noaa.gov EQUALANT]</ref><ref>[http://www.st.nmfs.noaa.gov/copepod/data/equalant/html_src/cruises.html nmfs.noaa.gov SHIP & CRUISE SUMMARY]</ref> A Coast and Geodetic Survey ship operated in the [[Indian Ocean]] for the first time in 1964, when ''Pioneer'' participated in the [[International Indian Ocean Expedition]].<ref>[http://www.history.noaa.gov/ships/pioneer3.html NOAA History, A Science Odyssey: Tools of the Trade: Ships: Coast and Geodetic Survey Ships: Pioneer]</ref>

===ESSA and NOAA years===
On 13 July 1965, the [[Environmental Science Services Administration]] (ESSA), was established and became the new parent organization of both the Coast and Geodetic Survey and the [[United States Weather Bureau]].<ref name="NOAA" /><ref name="timeline19001969"/> At the same time, the Coast and Geodetic Survey Corps was removed from the Survey{{'}}s direct control and replaced by a new '''Environmental Science Services Administration Corps (ESSA Corps)''' that reported directly to ESSA but retained the responsibility of providing commissioned officers to man Coast and Geodetic Survey ships.<ref name="NOAA" /><ref name="noaahistoryuscgs"/><ref name="timeline19001969"/>

On 3 October 1970, ESSA was expanded and reorganized to form the [[National Oceanic and Atmospheric Administration]] (NOAA). The Coast and Geodetic Survey ceased to exist as it merged with other government scientific agencies to form NOAA, but its constituent parts lived on, with its geodetic responsibilities assigned to the new '''National Geodetic Survey''' and its ships to the new [[NOAA ships and aircraft|NOAA fleet]], while the ESSA Corps became the new '''[[National Oceanic and Atmospheric Administration Commissioned Officer Corps]]''', or '''"NOAA Corps"'''. The National Geodetic Survey and the NOAA fleet both fell under control of NOAA{{'}}s [[National Ocean Service]].<ref name="NOAA" /><ref name="noaahistoryuscgs"/>

[[Image:Frank Thorn NOAA.jpg|thumb|right|160px|Frank Manly Thorn served as 6th Superintendent of the USC&GS.]]
[[Image:Admiral KARO NOAA obit.jpg|160px|thumb|right|Rear Admiral [[Henry Arnold Karo]] served as the 4th head of USC&GS.]]
[[Image:USS Pathfinder NOAA.jpg|thumb|right|275px|The USC&GS oceanographic research ship ''Pathfinder'' was re-commissioned as a US Navy vessel during World War II.]]

==Leadership==
===Superintendents (1816–1919)===
#[[Ferdinand Rudolph Hassler]], (1816–1818 and 1832–1843)
#[[Alexander Dallas Bache]], (1843–1865)
#[[Benjamin Peirce]], (1867–1874)
#[[Carlile Pollock Patterson]], (1874–1881)
#[[Julius Erasmus Hilgard]], (1881–1885)
#[[Frank Manly Thorn]], was the first non-scientist to head USC&GS (1885–1889)
#[[Thomas Corwin Mendenhall]], (1889–1894)
#[[William Ward Duffield]], (1894–1897)
#[[Henry Smith Pritchett]], (1897–1900)
#[[Otto Hilgard Tittmann]], (1900–1915)
#[[Colonel E. Lester Jones|Ernest Lester Jones]], (1915–1919)

===Directors (1919–1968)===
#[[Colonel E. Lester Jones|Ernest Lester Jones]], (1919–1929)
#[[Raymond Stanton Patton]], (1929–1937)
#[[Robert Francis Anthony Studds]], (1938–1955)
#[[Henry Arnold Karo]], (1955–1965)
#[[James C. Tison, Jr.]], (1965–1968)

===Superintendents of Weights and Measures===
*[[Ferdinand Rudolph Hassler]] (c. 1818–1843)
*[[Joseph Saxton]], (1843–1873);

== Ships ==
{{Category see also|Ships of the United States Coast and Geodetic Survey}}

A partial list of the Survey's ships:
[[Image:EXPLORER in Aleutians 1944.jpg|thumb|right|275px|The USC&GS ship ''Explorer'' in the Aleutian Islands in 1944.]]
* {{Ship|USC&GS|A. D. Bache|1871}} (in service ca. 1871-1900)
* {{Ship|USC&GS|A. D. Bache|1901}} (in service 1901-1917; 1919-1927)
* {{Ship|USC&GS|Arago|1854}} (in service 1854-1881)
* {{Ship|USC&GS|Arago|1871}} (in service 1871-1990)
* {{Ship|USC&GS|Barataria|1867|6}} (in service 1867-1885)
* {{Ship|USC&GS|Baton Rouge|1875|6}} (in service 1875-1880)
* {{Ship|USC&GS|Carlile P. Patterson}} (in service 1884-1918)
* {{Ship|USC&GS|Cosmos}} (in service 1887-1927)
* {{Ship|USC&GS|Dailhache|1913|6}} (in service 1919-1934)
* {{Ship|USC&GS|Davidson|1925}} (in service 1933-1935)
* {{Ship|USC&GS|Davidson|CSS 31}} (in service 1967-1970, then with NOAA 1970-1989)
* {{Ship|USC&GS|Discoverer|1918}} (in service 1922-1941)
* {{Ship|USC&GS|Discoverer|OSS 02}} (in service 1967-1970, then with NOAA 1970-1996)
* {{Ship|USC&GS|Drift}} (in service 1876-1893)
* {{Ship|USC&GS|Eagre}} (in service ca. 1870s-1903)
* {{Ship|USC&GS|Elsie III|1912|6}} (in service 1919-1944)
* {{Ship|USC&GS|Explorer|1904}} (in service 1904-1918; 1919-1939)
* {{Ship|USC&GS|Explorer|OSS 28}} (in service 1940-1968)
* {{Ship|USC&GS|Fairweather|MSS 20}} (in service 1968-1970, then with NOAA 1970-1989; 2004-present)
* {{Ship|USC&GS|Fathomer|1871}} (in service 1871-1881)
* {{Ship|USC&GS|Fathomer|1904}} (in service 1905-1942)
* {{Ship|USC&GS|Ferrel|ASV 92}} (in service 1968-1970, then with NOAA 1970-2002)
* {{Ship|USC&GS|George S. Blake}} (in service 1874-1905; famous as pioneer ship in deep-ocean survey and oceanography)
* {{Ship|USC&GS|Gilbert}} (in service 1930-1962)
* {{Ship|USC&GS|Guide|1918}} (in service 1923-1941)
* {{Ship|USC&GS|Guide|1929}} (in service 1941-1942)
* [[Hassler (vessel)|''Hassler'']] (in service 1871-1895)
* {{Ship|USC&GS|Heck|ASV 91}} (in service 1967-1970, then with NOAA 1970-1995)
* {{Ship|USC&GS|Hilgard|ASV 82}} (in service 1942-1967)
* {{Ship|USC&GS|Hydrographer|1901}} (in service 1901-1917; 1919-1928)
* {{Ship|USC&GS|Oceanographer|OSS 26}} (in service 1930-1942)
* {{Ship|USC&GS|Oceanographer|OSS 01}} (in service 1966-1970, then with NOAA 1970-1996)
* [[USC&GSS Pathfinder (1899-1941)|USC&GS ''Pathfinder'' (1899-1941)]]
* {{Ship|USC&GS|Pathfinder}}
* {{Ship|USC&GS|Pioneer|1918}}, in service 1922–1941
* {{Ship|USC&GS|Pioneer|1929}}, in service 1941–1942
* {{Ship|USC&GS|Pioneer|OSS 31}}, in service 1946–1966
* {{Ship|USC&GS|Silliman}}
* {{Ship|USC&GS|Thomas R. Gedney}}
* {{Ship|USC&GS|Yukon|1873}}
* {{Ship|USC&GS|Yukon|1898}}

==Flag==
[[File:Flag of the United States Coast and Geodetic Survey.svg|160px|thumb|right|The United States Coast and Geodetic Survey flag, in use from 1899 to 1970]]

The Coast and Geodetic Survey was authorized its own flag on 16 January 1899. The flag, which remained in use until the Survey merged with other agencies to form NOAA on 3 October 1970, was blue, with a central white circle and a red triangle centered within the circle. It was intended to symbolize the [[triangulation]] method used in [[surveying]]. The flag was flown by ships in commission with the Coast and Geodetic Survey at the highest point on the forwardmost mast, and served as a distinguishing mark of the Survey as a separate seagoing service from the Navy, with which the Survey shared a common [[ensign]].

The NOAA service flag, in use today, was adapted from the Coast and Geodetic Survey flag by adding the NOAA emblem—a circle divided into two parts by the white silhouette of a flying seabird, with the roughly triangular portion above the bird being dark blue and the portion below it a lighter blue—to the center of the old Survey flag. The NOAA symbol lies entirely within the red triangle.<ref>[http://mysite.verizon.net/vzeohzt4/Seaflags/noaa/noaa.html Sea Flags: National Oceanic and Atmoshperic Administration] at [[verizon]]</ref>


==See also==
==See also==
*[[Height Modernization]]
* [[Height Modernization]]
*[[Hydrography]]
* [[Surveying]]
*[[Topography]]
* [[Topography]]
*[[Surveying]]
*[[Nautical chart]]
*[[International maritime signal flags]]
*[[Lists of flags]]

==Notes==
{{reflist|group=Note}}


==References==
==References==
{{Reflist|2}}
{{reflist|2}}


==External links==
==External links==
* {{oweb|https://geodesy.noaa.gov/}}
{{Commons category|United States Coast and Geodetic Survey}}
*[http://geodesy.noaa.gov/ National Geodetic Survey website]
**[http://www.lib.noaa.gov/noaainfo/heritage/coastsurveyvol1/CONTENTS.html early history of the Coast Survey]
**[http://www.nauticalcharts.noaa.gov/ NOAA Office of Coast Survey]
**[http://docs.lib.noaa.gov/rescue/cgs/data_rescue_cgs_annual_reports.html U.S. Coast and Geodetic Survey Annual Reports, years 1837–1965]
*[http://www.arlingtoncemetery.net/uscgs.htm Timeline] at [[Arlington National Cemetery]] website
*[http://www.peakbagging.com/Benchmark.htm Explanation of survey monuments]
*1858 map: [http://texashistory.unt.edu/permalink/meta-pth-2473 ''Preliminary chart of entrance to Brazos River''] [http://texashistory.unt.edu/ hosted by the Portal to Texas History].
*1853 map: [http://texashistory.unt.edu/permalink/meta-pth-2481 ''Preliminary chart of San Luis Pass, Texas''] [http://texashistory.unt.edu/ hosted by the Portal to Texas History.]
*1854 map: [http://texashistory.unt.edu/permalink/meta-pth-2480 ''Preliminary survey of the entrance to the Rio Grande, Texas''] [http://texashistory.unt.edu/ hosted by the Portal to Texas History.]


{{ES_Government|state=collapsed}}
{{ES_Government|state=collapsed}}


{{Authority control}}

[[Category:Exploration of North America]]
[[Category:Geodesy organizations]]
[[Category:Geodesy organizations]]
[[Category:Geographic data and information organizations in the United States]]
[[Category:Government agencies established in 1970]]
[[Category:National Oceanic and Atmospheric Administration|National Geodetic Survey]]
[[Category:National Oceanic and Atmospheric Administration|National Geodetic Survey]]
[[Category:Government agencies established in 1807]]
[[Category:Exploration of North America]]

Latest revision as of 04:42, 11 May 2024

Not to be confused with Office of Coast Survey, National Ocean Service, United States Coast and Geodetic Survey, or United States Geological Survey.

The National Geodetic Survey (NGS) is a United States federal agency based in Washington, D.C. that defines and manages a national coordinate system, providing the foundation for transportation and communication, mapping and charting, and a large number of science and engineering applications. Since its founding in 1970, it has been part of the National Oceanic and Atmospheric Administration (NOAA), a division within the United States Department of Commerce.

Closeup of a United States Coast and Geodetic Survey marker embedded in a large rock in front of the Noroton Volunteer Fire Department in Darien, Connecticut
A survey marker in Wickenburg, Arizona
A metro survey marker at East Falls Church station in Arlington County, Virginia

History[edit]

Further information: United States Coast and Geodetic Survey

The National Geodetic Survey's history and heritage are intertwined with those of other NOAA offices. It traces its history to the Survey of the Coast, which was formed in 1807 as the first scientific agency of the United States federal government. It became the United States Coast Survey in 1836 and the United States Coast and Geodetic Survey in 1878, the latter name change reflecting the increasing role of geodesy in its work. Upon the creation of NOAA in 1970, the Coast and Geodetic Survey was abolished and its responsibilities were split among various agencies and offices of NOAA. The Coast and Geodetic Survey′s former geodetic responsibilities were placed under the new National Geodetic Survey in NOAA's National Ocean Survey (later renamed the National Ocean Service).

In 2009, former National Oceanic and Atmospheric Administration Commissioned Officer Corps officer Juliana P. Blackwell was named Director of the National Geodetic Survey, becoming the first woman to head either NGS or any of its ancestor organizations.

Purpose and function[edit]

The National Geodetic Survey is an office of NOAA's National Ocean Service. Its core function is to maintain the National Spatial Reference System (NSRS), "a consistent coordinate system that defines latitude, longitude, height, scale, gravity, and orientation throughout the United States".[1] NGS is responsible for defining the NSRS and its relationship with the International Terrestrial Reference Frame (ITRF). The NSRS enables precise and accessible knowledge of where things are in the United States and its territories.

The NSRS may be divided into its geometric and physical components. The official geodetic datum of the United States, NAD83 defines the geometric relationship between points within the United States in three-dimensional space. The datum may be accessed via NGS's network of survey marks or through the Continuously Operating Reference Station (CORS) network of GPS reference antennas. NGS is responsible for computing the relationship between NAD83 and the ITRF. The physical components of the NSRS are reflected in its height system, defined by the vertical datum NAVD88. This datum is a network of orthometric heights obtained through spirit leveling. Because of the close relationship between height and Earth's gravity field, NGS also collects and curates terrestrial gravity measurements and develops regional models of the geoid (the level surface that best approximates sea level) and its slope, the deflection of the vertical. NGS is responsible for ensuring the accuracy of the NSRS over time, even as the North American plate rotates and deforms over time due to crustal strain, post-glacial rebound, subsidence, elastic deformation of the crust, and other geophysical phenomena.

NGS will release new datums in 2022.[2] The North American Terrestrial Reference Frame of 2022 (NATRF2022) will supersede NAD83 in defining the geometric relationship between the North American plate and the ITRF.[3] United States territories on the Pacific, Caribbean, and Mariana plates will have their own respective geodetic datums. The North American-Pacific Geopotential Datum of 2022 (NAPGD2022) will separately define the height system of the United States and its territories, replacing NAVD88.[3] It will use a geoid model accurate to 1 centimeter (0.4") to relate orthometric height to ellipsoidal height measured by GPS, eliminating the need for future leveling projects. This geoid model will be based on airborne and terrestrial gravity measurements collected by NGS's GRAV-D program as well as satellite-based gravity models derived from observations collected by GRACE, GOCE, and satellite altimetry missions.[4]

NGS provides a number of other public services.[1] It maps changing shorelines in the United States and provides aerial imagery of regions affected by natural disasters, enabling rapid damage assessment by emergency managers and members of the public. The Online Positioning and User Service (OPUS) processes user-input GPS data and outputs position solutions within the NSRS. The agency offers other tools for conversion between datums.

See also[edit]

References[edit]

  1. ^ a b "National Geodetic Survey – What We Do". National Geodetic Survey Website. Retrieved May 27, 2013.
  2. ^ "New Datums". National Geodetic Survey. Retrieved March 21, 2017.
  3. ^ a b US Department of Commerce, NOAA, National Geodetic Survey. "Naming Conventions, New Datums". geodesy.noaa.gov.{{cite web}}: CS1 maint: multiple names: authors list (link)
  4. ^ US Department of Commerce, NOAA, National Geodetic Survey. "xGEOID16 Evaluation Computation". beta.ngs.noaa.gov.{{cite web}}: CS1 maint: multiple names: authors list (link)

External links[edit]

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