This paper is a summary of a 1980 research study initiated by the Marine Technology Society and several U.S. government agencies to identify requirements for marine geodetic applications in support of national objectives in ocean science, engineering, and operations over the next two decades. The study established a broad definition of marine geodesy to form a base for marine geodesy's several maritime applications. The study investigated the following areas: bathymetry, hydrography, marine gravity and geophysics, positioning and navigation, plate tectonics/seafloor spreading, ocean surface topography, mean sea level, and tsunamis.