Autofocusing Reflecting Projector 
The autofocusing reflecting projector 
(Figure 9) is designed for projecting opaque 
objects, photographs or maps onto a map 
manuscript under compilation so the de- 
tail can be rapidly traced on the new map 
sheet. The instrument is useful in map re- 
vision as well as map compilation. It will 
project a 9 by 9 inch area at any magnifi- 
cation from § to 3.5. It is electrically 
ARMY MAP 
CONTRIBUTIONS 
Although aerial photography had been 
utilized at the Army Map Service in com- 
pilation techniques prior to 1945, it was 
not until March of that year that a sepa- 
rate Photogrammetric Division was es- 
tablished. Contributions by AMS in the 
years preceding this were: 
a. The development in 1944 of the AMS 
Method of Tilt Anlaysis, described in 
AMS Bulletins Nos. 12! and 192. 
b. Introduction in 1944 of the method 
of preparing printed photo-maps on the 
reverse side of the companion line maps. 
Associated with this method was the pro- 
cedure of laying the mosaic to a ‘‘blueline’”’ 
image of the line map which was processed 
onto a stable-backed (metal or masonite) 
sheet of paper. 
The most important Army Map Service 
contributions in the field of photogram- 
metry during the post war years have been 
in aerial triangulation and aerial photog- 
raphy. 
a. Army Map Service, together with 
the Engineer Research and Development 
Laboratories, modified the Zeiss Stereo- 
planigraph to accommodate 6 inch Metro- 
gon photography. 
b. Starting in 1946, and continuously 
since then, Army Map Service has con- 
ducted extensive tests of aerial triangula- 
tion methods using Multiplex and Stereo- 
planigraph equipment.? Particular con- 
sideration was given to the development 
of practical methods for adjusting the re- 
sults obtained from the instruments. The 
application of these methods to production 
work was begun in 1948. 
c. Included in the aerial triangulation 
studies has been the use of the barometric 
20 HISTORY OF PHOTOGRAMMETRY IN THE UNITED STATES 
driven and incorporates a chain driven 
pythagoras inverter to maintain the pro- 
jection in sharp focus at all enlargements. 
The illuminant is two 500-watt incan- 
descent lamps. Provision is made for han- 
dling large rolled maps so that any selected 
portion may be projected. The instrument, 
now a standard item, is designed for in- 
stallation and operation in a van type 
truck, weighs about 380 pounds and is 74 
inches high at the point of highest travel. 
SERVICE* 
altitudes of consecutive exposures on a 
flight strip, as recorded on the film by the 
type T-5 aerial cameras. These data have 
been found to be of extreme value in 
bridging and Army Map Service has speci- 
fied such recordings on military projects 
since 1946 and by commercial aerial photog- 
raphy concerns in 1951. 
d. Other test work in aerial triangula- 
tion was carried out on the Stereoplani- 
graph in 1950 in which coordinates for all 
points were read from the counters on the 
instrument instead of plotting graphically 
by the coordinatograph. Instrument co- 
ordinates were related to survey coordi- 
nates by mathematical techniques, but 
the method has not yet been applied on 
operational assignments. 
e. During World War II, some U. S. 
military organizations utilized slotted tem- 
plets in conjunction with the Multiplex 
and, when appropriate, Army Map Service 
has continued the use of the method. In 
this application, the Multiplex models are 
first oriented to the best possible approx- 
imation of scale. Pass points are plotted 
from the Multiplex models and these are 
used to cut templets at the Multiplex 
scale. Templets are assembled in a con- 
trolled lay-down in large blocks to deter- 
mine final pass point positions. 
f. As part of its plan to obtain complete 
topographic map coverage of the United 
States at 1:250,000 scale, the Army Map 
Service initiated a program in 1947, now 
at an accelerated pace, to compile maps 
by photogrammetric methods wherever 
suitable large-scale map source is non- 
existent. From an economic standpoint, 
this necessitated the use of high altitude 
photography. Since the first commercial 
contract in 1947, approximately 315,000 
* Paper approved for publication 13 May 1952 by office of Public Information Department 
of Defense. 
     
   
     
   
  
  
  
  
   
   
    
   
   
   
   
  
  
   
    
   
   
  
   
  
  
   
   
  
   
  
   
   
  
  
   
  
  
   
  
  
  
   
  
   
  
  
  
   
   
   
   
   
   
  
  
  
   
  
  
    
   
    
     
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