Part 11 

 THE STEREOj PAIRS, AND THE INTERPRETATION AND ANALYSIS 

 OF THE DIRECTIONAL SPECTRUM IN TERMS OF WAVE THEORY 



Introduction 



Of the one hundred stereo^pairs of photographs taken by the two aircraft, 

 three were selected by the Photogrammetry Division for spot heigljt readings on 

 the basis of picture quality and lack of cloud shadow areas. After leveling, Data 

 Set 1 was found to have a serious barrel distortion so it had to be abandoned. 

 The original nuraerical analysis of the two remaining sets and the numerical 

 analysis of the reduced data, were described in Part 9. In this part, the diffi» 

 culties which were encountered in analyzing the original results, the way the 

 decision was reached to use a smaller area of points^ and the results of the 

 analysis of the modified data will be described* 



The stereo pairs 



The two sets of stereo pairs chosen for analysis are shown i^ figures 



i 



•1 

 ll.l(A)s 11, 1(B), ll.ZCA);, and 1.1.2(B) where the lead plane picture is the first one 



of the pair. In order to be sure that the photographs chosen were not chosen, 

 say, for high waves in the vicinity of the ATLANTIS, 10 photographs as taken 

 from one of the planes were picked at random, from the 100 photographs 

 available and the wave patterns in th,e vicinity of the ATLANTIS were com- 

 pared qualitatively with eacl^ other and the two photographs chosen for analy* 

 sis„ There was no apparent difference in wave heights or wave patterns, so 

 that it seemed safe to assume that the two pairs chosen for numerical analy- 

 sis were representative within usual sampling variation of the sea state. 



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