The output from the SYNC0N2R program is a contour plot of 

 the MSQLOC area. Although this output is not a primary product 

 of the system, it is used for checking and may be a useful 

 byproduct as rough automated contours. Because of the 5 -minute 

 cell size and the nature of the interpolation scheme, large 

 flat areas tend to break up on the contour plot. This break up 

 of contours is not an error in the data and does not affect 

 the profile generation. To improve the contour output aesthe- 

 tically, the interpolation can be improved by adding contours 

 in key locations. In areas of rough topography this improvement 

 will not be necessary. The first example, around seamounts or 

 a seamount group, is shown in figure A-1. Usually the added 

 contour is placed outside the base contour to cutoff or terminate 

 the interpolation adjoining a flat area or to define the sea- 

 mount base. The second example is for domes, rises, ridges or 

 tablemounts (fig. A-2) . Here the added contours are on the top 

 of the structure in order to cutoff or terminate the interpolation 

 on their flat or gently rounded summits. The third example is 

 for noses or spurs (fig. A-3) . Although this feature is similar 

 to those in figures A-1 and A-2, short disconnected contours may 

 be needed if the spur slopes are gentle. In all these examples, 

 the track direction was assumed to be left to right. 



The boundary condition is a special case of endpoint inter- 

 polation. Whenever an island or continent is encountered, the 

 zero contour or sea level is handled as shown in figure A-4 . 

 On the SYNC0N2R program the zero-contour level should never be 

 plotted, but the 1-fathom or 1-meter contour should be inter- 

 polated to show the coast line. In profiling, the punched card 

 depth values after the first zero usually are discarded and the 

 profile terminated at that range. 



A-2 



