Details of the grid arrangement were worked out. BuAer was notified that 



the operational part of SWOP was over and all concerned were thanked for 



« 



their help and cooperation,, A similar letter was sent to NADU via their 

 boss, the Commanderj Uo S- Navy Air Basesj 1st Naval District. 



The films exposed over tlie North Atlantic were developed and sent to 



m 



me HydrograpMc Office. The low light intensity available during the SWOP 

 flight threatened to produce negatives of ;naargiiial value, but careful develop- 

 ment by the NPC at Anacostia sa.ved the day. 



Hydro looked over the stereo pairs, picked one of the best and began 

 contouring. 



Furtlier work caume to a temporary halt while Hydro's presentation of 

 the contours were sent to Pierson and Marks for stady. As was expected 

 there was some tilt in the contoiu-ing. The Photogrammetry people at Hydro 

 did their best to level the stereo-pair befoire contooiringj but we all realized 

 that with no established reference plane from ^rhich to work, perfect level- 

 ing would be impossfbleo The contours showed a range of heights from 

 one foot to 24 feet wliile actual wave pole measui-ements tak.en on the 

 spot frorn. the ATLANTIS gave a sigaiiicant wave height of about 7 feet. 

 In addition to tliis tilt a somewhat closer look showed a ridge running al- 

 most exactly down the center of tlie 2, 000' x 4, 000' rectangle caused by the 

 stereo-photos paralleled by a trough about 500' away. In order for this 

 feature to be real, a wave with a height of at least 9 feet and a period of 



about 14 seconds would have been in the area photographed. No such wave 



11 



