will indicate if the MSQLOC area has been structured correctly. 

 An even more efficient method of checking is to pass the gridded 

 bathymetric data through the SYNC0N2R program. 



The SYNC0N2R program (fig. 7) plots contours of the gridded 

 data on a Mercator projection at the same scale as the source 

 manuscript. The source manuscript can be overlain by the 

 gridded-data contour plot, for a comparison of content and 

 form. This plotting check requires a 29-inch drum plotter or 

 equivalent, while the SYNC0N2R program itself requires a control 

 card (fig. 11). In addition, the DATA statement variable (CL) 

 requires a specification of the contour levels that will be 

 plotted (see app. B) . An optional DATA statement variable 



(LABELS) can be used if labels are desired (see app. B) . If the 

 SYNC0N2R plot is satisfactory, the gridded bathymetry is loaded 

 on the random-access storage device via the loading program 



(SYNBLOCK) , fig. 7) . 



Before a block of gridded data can be loaded on the random- 

 access storage device, the device must be primed with a traffic 

 director program (SYNTABLE, fig. 7) . SYNTABLE is a predetermined 

 "look-up" table, which gives SYNBLOCK basic information that is 

 needed to place a block of gridded data in its proper address on 

 the device. Using the MSQLOC area number as the key, the table 

 supplies the relative address, the actual block size to be 

 transmitted, and a file key or name. The file key indicates by 

 name in which file in the storage device a particular block of 

 data is to be placed. An example of the "look-up" table printout 

 is given in table 1. In the DATA statement N is equal to the 

 number of MSQLOC areas now on the "look-up" table. The relative 

 address is the physical location from the beginning of the file 

 of the first word of the data block. The actual block size is the 

 quantity of storage required to contain the data plus the 

 identification groups and is an even multiple of 32 (Aiken, et al. 

 1970) . The storage requirement for the actual block size is 

 predetermined and is listed in table 2 by hemisphere latitude 

 bands, which include the overlap. 



Using the "look-up" table from SYNTABLE on the random-access 

 storage device, a block of gridded bathymetry can now be loaded 

 by SYNBLOCK. The punched deck of gridded data is preceded by 

 two header cards. The first card contains the number of sets to 

 be loaded and the second card, one for each set, specifies the 

 MSQLOC area number and the column and row information obtained 

 from table 2 (see app. B for exact card formats) . The DATA 

 statement N is equal to the number of MSQLOC ' s presently on the 

 "look-up" table. SYNBLOCK then looks up the file, the relative 

 address, and the block-size information from the preloaded table 

 for each MSQLOC area and places the data in its proper location. 

 An identification group containing the following is placed at the 

 end of the data block: 



19 



