Accuracy of Results 



Reconnaissance-type film was used erroneously in the aerial ca^neras 

 itsstead of the more stable topo=base filna. The film furnished this Office 

 was not dJj:nensiona.lly stable^ and made the recapturing of the precise in- 

 strument settings ixnpossible when the last model was re-compiled. There- 

 for e^, the final, photogrammetric solution could not match all the computed 

 va].ues„ This explaijis the discrepancy in holding all eight points as de- 

 scribed above. The computed values for the leveled data are more valid 

 since tb.ey are substantiated by the leveled graphic analysis which shows 

 about equal areas above and below sea level. 



The final graphic forwarded to N. Y. U. exhibits both contour and 

 spot=lj,eigM information over the nearly 5 million square feet of ocean 

 surface. The spot height accuracy is +0.05 mm (at 1:3,000 scale) or 

 i:. 0.5 feet. The contour interval is 3 feet and is accurate to +0,2 mm 

 oi i; 2 feeto The relatively short distance represented by the ATL.ANTIS- 

 rait combination is not adequate to assure a precise horizontal scale^ and 

 the horizontal accuracy is estimated to be +2 feet. 



48 



