CHARTING THE OCEANS FOR SAFE NAVIGATION 73 



High precision stereoscopic plotting systems are used by the Naval 

 Oceanographic Office to compile data from atrial photographs. 



begun on a precision automatic digital coordinatograph system. 

 The first such system was placed in operation in the Naval 

 Oceanographic Office in June 1963. The system is capable of 

 drawing, scribing (engraving), or photographically exposing 

 continuous straight or curved lines; printing numerical data with 

 a mechanical print head; and photographically exposing alpha- 

 numeric data on large sheets of sensitized film. Information 

 processed by the plotter system may be in the form of computer- 

 prepared magnetic tape (used 95 percent of the time) or punch 

 paper tape. The system may also be controlled from a keyboard 

 input unit. An integral part of the system is a director unit, 

 which controls the coordinatograph and the operations of its 

 interchangeable instrument heads in response to information fed 

 into it. 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 an inked plastic or paper 

 sheet, a photographic film, or a scribed negative. The charted 

 detail is plotted and delineated at a speed and to a tolerance that 



