CODED INFORMATION ON APERTURE CARD 



SOURCE Symbol for the source holding the film. Appendix A 



lists the sources and their symbols and addresses. 



SUBJECT Letters or numerals assigned by a source for a photo- 

 graphic mission (UNK=unknown ; VAR=variable numbers 

 assigned) . 



DATE The year the mission was flown. 



FOCAL LENGTH .... Focal length of camera in inches. 



SCALE Scale of the vertical photograph in thousands (i.e. 



020=1:20,000; 005=1:5,000. Oblique photographs are 

 coded as: OBL. 



ENGINEER DISTRICT. . Symbol of the applicable U.S. Army Corps of Engineers 

 Division or District. 



SEQUENTIAL NUMBER. . A unique number assigned to each aperture card for 

 each U.S. Army Corps of Engineers District. 



MAP SHEET DMATC identification for the 1 :250 ,000-scale topo- 

 graphic map used to plot the photography or imagery. 



CLASSIFICATION . . . Security classification (i.e. 00-0=Unclassified; 

 02-0=For Offical Use Only). 



STATE State abbreviation for area covered by topographic 



map (See Appendix C) . Number after abbreviation is 

 DMATC designation for plot used in defining area 

 covered by film image; outline on film image is 

 ground covered by photographs. 



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