INTRODUCTION 



The need for a computerized bathymetric data bank and 

 techniques for rapidly manipulating large quantities of data 

 became evident as demand upon the Naval Oceanographic Office 

 for bathymetric profiles increased and became more urgent. It 

 became increasingly difficult to satisfy these demands through 

 manual compilation of depth soundings, contouring, and profile 

 constructions. A massive recompilation and reanalysis of 

 bathymetric data, systematic revision of all bathymetric charts 

 in the North Atlantic and North Pacific Oceans, including 

 extension of chart coverage to the equator, was underway. At 

 the same time the impracticality of using the existing data bank 

 of bathymetric soundings for machine generation of profiles 

 became apparent. The need for a specialized bathymetric data 

 bank to support acoustic - oceanographic modeling gave rise to 

 development of a synthetic bathymetric profiling project using 

 the new bathymetric contour charts as the data base. The project 

 developed procedures for digitizing the contour charts, and 

 computer programs and subroutines for data storage and retrieval 

 and for profile generation. Mr. Thomas M. Davis, Naval Oceano- 

 graphic Office, provided special assistance in developing 

 programs SPLINT (SYNGRID) , BURNS (SYNC0N2R) , BATHY (subroutine 

 BATHY) and DAWHAT (SYNCHEX) and contributed to the basic philosophy 

 regarding SYNBAPS. Mr. J.D. Brown, Naval Oceanographic Office, 

 assisted in the software development and digitization of the test 

 data. 



Funds for this project were provided by the Office of Naval 

 Research through the Long Range Acoustic Propagation Project. 



One of the basic inputs to most Navy long-range, acoustic 

 propagation models are bathymetric profiles in digital form. These 

 profiles usually are plotted along a great-circle path (glossary) 

 as a function of range versus depth. Two methods of generating 

 such profiles generally have been employed. In the first, a ship 

 sails a predetermined great-circle path collecting continuous 

 bathymetry using a precision depth recorder (PDR) . If the course 

 is accurately adhered to, the PDR record can be merged with the 

 navigational record to obtain the bathymetric profile. If the 

 navigational record is poor, the track of the ship will have to 

 be adjusted and normalized to obtain a satisfactory bathymetric 

 profile. A profile thus produced is accurate and retains most 

 of the high frequency information but is costly in ship time, 

 hard to schedule, and usually results in only a single profile. 



