in driven 
| the pro- 
rgements. 
tt incan- 
e for han- 
y selected 
strument, 
ed for in- 
van type 
and is 74 
st travel. 
res on a 
Im by the 
lata have 
value in 
has speci- 
7 projects 
al photog- 
triangula- 
ereoplani- 
tes for all 
ers on the 
raphically 
ment co- 
y coordi- 
ques, but 
pplied on 
me U. S. 
tted tem- 
Multiplex 
ip Service 
ethod. In 
1odels are 
e approx- 
€ plotted 
these are 
Multiplex 
in a con- 
to deter- 
complete 
1e United 
rmy Map 
1947, now 
pile maps 
wherever 
> is non- 
andpoint, 
1 altitude 
mmercial 
y 315,000 
lepartment 
square miles of this special photography 
has been acquired. The Army Map Serv- 
ice has encouraged the use of high alti- 
tude photography and has pioneered in the 
use of this photography for medium-scale 
stereocompilation.4 
g. Where the method may be applied 
advantageously, the Army Map Service 
has since 1947, employed dual flight alti- 
tudes for the same project area. In this 
technique, the higher altitude photog- 
raphy is utilized for horizontal control ex- 
tension through aerial triangulation, and 
the lower altitude photography on which 
the established photogrammetric control 
is identified, is used in conventional com- 
pilation. This procedure reduces costly 
field work without a sacrifice in accuracy. 
h. Army Map Service continued the 
practice followed by the military services 
during the past war, of using large-scale 
photography for intensification of detail 
being compiled from smaller scale mapping 
photography. 'This larger scale supple- 
mentary photography is taken simultane- 
ously with the mapping photography. In 
1951, for the first time, due to an Army 
Map Service procurement specification, 
a civilian firm in the United States made an 
installation of this type to fulfill the stated 
requirements. 
i. Beginning in 1939, the Corps of En- 
gineers, through its District Offices, ini- 
tiated the requirement for performance 
testing of aerial cameras.’ This system pro- 
vided for flying the aerial cameras over 
a fully-controlled area and setting stereo- 
scopic models to check the resulting ac- 
curacy when used under actual operating 
conditions. This testing was performed 
prior to each photographic project and 
periodically thereafter as required. Since 
1946, Army Map Service has elaborated 
this testing so that camera performance is 
now checked by laboratory calibration, 
flight perfomance testing over controlled 
areas, and inspection of every roll of proj- 
ect film for distortion within a short time 
after exposure and development. The last 
part of the testing is made by setting check 
stereo models. 
RELATED CONTRIBUTIONS TO THE PHOTO- 
GRAMMETRIC FIELD 
These contributions are: 
a. The Corps of Engineers has, since 
   
   
  
  
    
    
  
     
  
    
   
    
  
   
    
    
   
   
    
    
   
   
   
   
   
   
  
  
    
    
  
  
  
   
  
  
   
   
   
  
   
     
   
   
  
     
  
   
   
    
  
   
    
  
  
  
   
   
    
  
   
    
  
  
  
PHOTOGRAMMETRIC ENGINEERING 21 
1939, used a "'classification survey" system 
of collecting cultural information such as 
place names, road classification and simi- 
lar data, in advance of the map compila- 
tion process. This information which is 
secured in the field, is annotated on the 
aerial photographs for subsequent office 
use. 
b. In 1948 the Army Map Service 
Geodetic Division established an extensive 
controlled area for testing aerial photo- 
graphic equipment and photogrammetric 
mapping methods.® This area has individ- 
ual horizontal and vertical picture con- 
trol points as well as combined control 
points spaced at measured intervals. The 
points are all photo-indentifiable, either 
through construction on the ground or be- 
cause of their natural or structural char- 
acteristics and location. The control in this 
area is being maintained and is inspected 
and serviced at biennial periods to insure 
its availability for its intended purpose. 
BIBLIOGRAPHY 
1. “The A.M.S. Method of Tilt Analysis,” 
A.M.S. Bulletin No. 12, C. of E., Dept. of 
the Army, Washington, D. C., Oct. 1944. 
2. “Notes on the A.M.S. Method of Tilt 
Analysis,” A.M.S. Bulletin No. 19, C. of E., 
Dept. of the Army, Washington, D. C., 
Aug. 1945. 
3. Brandt, Robert S., “Discussion of Spatial 
Triangulation with the Zeiss Stereoplani- 
graph,” PHOTOGRAMMETRIC ENGINEERING, 
Vol. XIV, No. 3, Sept. 1948. 
, ‘Aerial Triangulation with the 
Stereoplanigraph," PHOTOGRAMMETRIC EN- 
GINEERING, Vol. XVI, No. 4, Sept. 1950. 
, ‘Resume of Aerial Triangulation 
Adjustment at the Army Map Service,” 
PHOTOGRAMMETRIC ENGINEERING, Vol. 
XVII, No. 5, Dec. 1951. 
  
  
4. Dickerson, Lewis A., ''Use$ of High Altitude 
Photography for Mapping and Reconnais- 
2% 
sance,' PHOTOGRAMMETRIC ENGINEERING, 
Vol. XVI, No. 1, March 1950. 
5. Webb, James P., “Performance Testing of 
Aerial Cameras for Photogrammetric Map- 
ping," PHOTOGRAMMETRIC ENGINEERING, 
Vol. XVIII, No. 1, Mar. 1952. 
. Hopkins, Page, ‘Establishing Control for 
Aerial Mapping Test Area in Southern 
Arizona," Surveying and Mapping, July- 
Sept. 1951.