

10 



10 



II 10 



^O' 



standard deviation would have to include the 



is the 



sliip's errors; i.e., a- 



--^ij. 



r+o-/, where 



map standard deviation taken from the depth error 

 diagram, and a^ is the ship standard deviation. 

 The ship standard deviation may be estimated as 

 the square root of the first three terms on the 

 ri2;ht-hand side of equation 2. 



Diagram of the Standard Deviation of the Isobath 

 Position Error 



The standard deviations in the isobath position 

 error diagram are estimates of how much and how 

 frequently the positions of the depths as indicated 

 on the maps may depart from the true positions. 



This diagram is also based on the square root of 

 equation 2; it shows the average standard devia- 

 tion in 5-minute unit areas and applies only to 

 indicated depths — not to the original soundings. 

 The values in the diagram were computed by 

 dividing the standard deviations of the isobath 

 depth error (fig. 2) by vFe+^', where ^ is the mean 

 topographic slope of the sea floor in a given 5- 

 minute unit area, and V^ is the variance of the 

 topographic slope within the same 5-minute unit 

 area. A more detailed diagram of the entire 

 mapped area is reproduced in figure 3. 



The figures in this diagram may be used to esti- 



BATHYMETRIC MAPS AND GEOMORPHOLOGY OP MIDDLE ATLANiTIC CONTINENTAL SHELF 



45 



