could have been generated by any known meteorological disturbance in the 

 Atlantic area. We were forced to conclude that the contoured surface was 



not only tilted but warped in some sort of "barrel" shape with axis parallel 

 to the long sides of the contoured rectangle. Fortunately, this barrel type 

 of distortion was not present in other stereo pairs and the only real problem 

 turned out to be that of removing tilt from the analysis and determining a 

 zero reference plane. 



The tilt was not too serious. Mathematical analysis could take most 

 of the tilt out of the data. After a discussion with Hydro, it was suggested 

 by me that we have Hydro give us the data in the form of discrete elevations 

 on a grid system. They felt that such data would be nnore accurate and take 

 less time than contouring. It looked as if it were about time for another 

 small conference to see where we stood a.nd determine just what should be 

 done. 



Dr. Pierson came down from NYU on the first of March and we had a 

 viry profitable discussion with the people at Hydro's Photogrammetry 

 Branch. He was finally able to decide on a simple 30 x 30 foot grid sys- 

 ta:m. with sides parallel to the photographs. Unfortunately, the sides of the 

 photographs did not line up with the direction of the surface waves as ex- 

 pected. The preliminary analysis of the data is described in Part 7 of 

 this report. 



The important thing, however, was to have the grid system point in 



the same geometrical direction in each of the three pairs of photographs 



12 



I 



