NATIONAL OCEANOGRAPHIC PROGRAM LEGISLATION 215 



The plan calls for the establishment of a network of horizontal control with 

 spacing to meet the economic needs of the particular area involved. This 

 spacing varies from 3 to 4 miles in urban areas to 10 to 15 miles in mountainous 

 areas in the West and Alaska. These limits will change as our economy expands 

 and the density of population increases. In the case of vertical control, it is 

 planned to establish leveling lines at approximately 6-mile intervals in urban 

 areas with bench marks spaced one-half to 1 mile apart along these lines, and 

 to provide 10- to 15-mile line spacing, with bench marks at 1 mile intervals, 

 throughout the rest of the country, except in mountainous areas and in Alaska 

 where spacing will be at approximately 25-mile intervals. 



Another objective of the geodetic program is the determination of the exact 

 size and shape of the earth so that a more accurate spheroid may be determined 

 to serve as the base for latitude and longitude positions. Through gravity and 

 astronomical observations the differences between geoidal and ellipsoidal sur- 

 faces will be determined. Space tracking, missile trajectories, and many sicen- 

 tific aspects of geophysics depend upon this geoidal separation in data reduction. 



Hydrography. — This i>rogram is concerned with aU the various operations 

 involved in the production of nautical charts and related publications required 

 for the safety of marine navigation. It includes such activities as hydrographic 

 surveys, including the operation of ships; coastal photogrammetric surveys and 

 mapping ; geodetic control surveys ; current and circulatory surveys ; tidal sur- 

 veys ; investigations of hazards to navigation ; charts compilation and mainte- 

 nance ; reproduction and distribution of charts, tidal and current data, and coast 

 pilot information ; and research and development in instrumentation, automa- 

 tion, and cartographic techniques. 



Nautical charts are published in several scales and formats to meet the needs 

 of all maritime interests, including maritime commerce, the fishing industry, 

 small recreational craft owners, national defense, and for exploration and de- 

 velopment of marine resiuorces. 



The objectives of the program are to complete and maintain on an up-to-date 

 basis the charting of the coastal areas, including harbors and estuaries, of the 

 United States and its iwssessions. Included also is the charting for recreational 

 boating purposes of lakes and reservoirs which are not included tn the areas of 

 responsibility of other agencies of G-ovemment. 



A substantial i>art of the program involves chart maintenance to insure that 

 they provide the information needed for safety of navigation. Chart revisions 

 and maintenance consisting of corrections to existing charts account for approxi- 

 mately 55 percent of the annual cost of chart preparation. An indication of 

 the magnitude of the chart maintenance program is the fact that there are 

 approximately 90,000 linear miles of coastline around the United States and 

 its possessions, and the areas in which nautical charting is required comprises 

 over 2 million square miles. 



Aeronautical charting. — The program in aeronautical charting involves each 

 activity required for the production and maintenance of aeronautical charts and 

 related publications needed for the safety and control of air navigation in the 

 United States and its jwssesisions. It includes field surveys and investigations ; 

 compilation, reproduction, and distribution and research and development in por- 

 trayal of aids to the navigator. 



Aeronautical charts consist of two main series — visual and instrument. The 

 visual charts provide considerable topographic cultural, and aeronautical detail 

 to enable pilots operating under visual flight rules to check their position at all 

 times. Instrument charts are designed to provide the air pilot with the infor- 

 mation required for instrument navigation and radio communication to rapidly 

 determine his precise location when operating by instruments only. Both series 

 of charts are used by private pilots, commercial airlines, and the military services. 



Requirements, in terms of format and information to be shovpn on aeronautical 

 charts, are determined by the Federal Aviation Agency in carrying out its 

 responsibility for administering the Federal airways system. A major part of 

 the aeronautical charting program involves the revision of charts to implement 

 changes in procedures and regulations adopted by the FAA to improve its system 

 of air traflac control. 



