PREDICTION AND SURVEY 95 



and controls the coordinatograph and the operations of its interchange- 

 able instrument heads. The plotter operates on the principle that any 

 curved line that can be described by a mathematical equation can be 

 automatically produced by the system. 



The final output of the automatic plotter system consists of inked 

 plastic or paper sheets, a photographic film, or a scribed negative. The de- 

 tail on these outputs is plotted and delineated at a speed and to a tolerance 

 that cannot be matched by manual methods. 



Considerable progress has been made in developing a library of computer 

 programs to construct different types of cartographic functions. Com- 

 puter programs already developed and in use on the digital coordinato- 

 graph are: 



1 . Construction of electronic navigational position lattice systems, both 

 hyperbolic (loran, etc.) and circular (shoran, etc.) for charts and oceano- 

 graphic/hydrographic survey plotting sheets. 



2. Construction of over 30 different map projections. 



3. Annotation and plotting of soundings resulting from hydrographic 

 surveys, automatically plotting the soundings in their proper latitude and 

 longitude position and annotating the correct depth in fathoms and feet. 



4. Plotting and scribing of geographic shoreUne and other map features. 



5. Delineating the major great-circle sailing routes and underwater 

 cable routes of the world. 



6. Production of magnetic variation and declination charts of the world. 



7. Scribing of various metric plotting grids and military reference 

 grids for overprinting on nautical charts. 



Numerous requests for automatic services have been filled from other 

 government agencies, private institutions, and foreign governments. In 

 addition to providing production assistance, technical information, guid- 

 ance, and computer program documentations have been supplied freely 

 to help others develop similar capabilities. 



By using unique computer programming techniques, an automated 

 cartographic system can produce in eight hours as many as twelve chart 

 originals, completely plotted, scribed, and ready for photolithographic 

 production. Stops are required only for changes in scribing materials and 

 magnetic tapes. In the four years the plotter has been in operation, over 

 7000 individual original drawings and color separation originals have been 

 produced. 



Automatic cartographic production systems will be added in 1967 to 

 provide more advanced capabilities, automatically placing names and 



