page_title: U.S. National Geodetic Survey
section_title: Interwar period
hierarchical_section_title: U.S. National Geodetic Survey / History / Interwar period
caption_attribution_description: English: USC&amp;GS marker at Fort McAllister, Georgia, USFrom outside ring inward:U.S. COAST &amp; GEODETIC SURVEY REFERENCE MARKFOR INFORMATION WRITE TO THE DIRECTOR WASHINGTON D.C.$250 FINE OR IMPRISONMENT FOR DISTURBING THIS MARKFT MCALLISTER 1932NO 2
context_page_description: The National Geodetic Survey, formerly the United States Survey of the Coast, United States Coast Survey, and United States Coast and Geodetic Survey, is a 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, of the United States Department of Commerce.
  The National Geodetic Survey's history and heritage are intertwined with those of other NOAA offices. As the U.S. Coast Survey and U.S. Coast and Geodetic Survey, the agency operated a fleet of survey ships, and from 1917 the Coast and Geodetic Survey was one of the uniformed services of the United States with its own corps of commissioned officers. Upon the creation of the Environmental Science Services Administration in 1965, the commissioned corps was separated from the Survey to become the Environmental Science Services Administration Corps.
context_section_description: 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. In 1923 and 1924, it began the use of 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 sound fixing and ranging (SOFAR) channel or deep sound channel (DSC) – a horizontal layer of water in the ocean at which depth the speed of sound is at its minimum – and to the development of telemetering radio sonobuoys and marine seismic exploration techniques. The Air Commerce Act, which went into effect on May 20, 1926, among other things directed that the airways of the United States be charted for the first time and assigned this mission to the Coast and Geodetic Survey.
  In 1933, the Coast and Geodetic Survey opened a ship base in Norfolk, Virginia. From 1934 to 1937, it organized surveying parties and field offices to employ over 10,000 people, including many unemployed engineers, during the height of the Great Depression.
caption: A 1932 marker at Fort McAllister Historic Park in Bryan County, Georgia.
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