special geographic maps of the seas and oceans that are designed for ship navigation and for solving other problems related to the study and use of the world’s oceans for economic and scientific purposes.
Marine maps are compiled and published by hydrographic (oceanographic) services. In the USSR they are prepared by the Main Administration of Navigation and Oceanography of the Ministry of Defense. Depending on their purpose and content, marine maps are subdivided into three groups: navigation charts, special purpose maps, and reference and auxiliary maps.
Special purpose maps are used to meet the needs of the navy. Reference and auxiliary maps include maps whose purposes and content are not used directly for ship navigation but help in solving both navigational and other problems on the applied and scientific levels. Examples of such maps are maps of the time zones, maps of the elements of terrestrial magnetism, and many other maps in the Marine Atlas. Auxiliary maps also include orthodromic maps (for selecting sailing routes along the great circles), boat maps (for ensuring arrival of lifeboats at the nearest shores or islands when ships are wrecked), and maps with generalized or reduced general geographic features that are usually used as cartographic bases (blank forms) in preparing various graphic documents and materials.
K. A. BOGDANOV