Figure 1 
TARGET FOR PLACEMENT ON 
MARKERS OF SURVEY CONTROL 
\ 
N QN 
Leg for ease in finding NX 
t t t 
arget on photographs S X 
N s 
Dirt.) yS' , in which S' = photography scale in 
5 feet to one inch. 
D (ft.) „/_3_ » in which S is the denominator of the 
300 representative fraction 
of the photography scale. 
D (meters) = a S x, in which S is the denominator of 
3,000 the photography scale 
expressed as a representative 
fraction. 
A significant advantage of this target design is that the 
target size determined by use of these equations for a 
particular photography scale will be adequate for photog- 
raphy of all larger scales, but not vice versa.