COMMISSION IV WI 
| Aopendix to the INT, ARCHI | 
DTOGRAMMETRY, Vol. Xlk4, *^75 : 
Reprinted from 
PHOTOGRAMMETRIC ENGINEERING 
April 
1956 
Economic Factors in the Integrated Photogrammetric 
System of the U. S. Geological Survey*t 
GEORGE D. WHITMORE, U. S. Geological Survey 
"T United States Geological Survey is now in the process of affecting im- 
portant changes in its mapmaking procedures. These integrated changes 
affect all the major aspects of the topographic mapping operation: aerial photog- 
raphy, photogrammetric instruments, plotting techniques, field operations, 
cartographic finishing, and reproduction processes. It is the purpose of this 
paper to review the economic background of this transformation and to discuss, 
in simple terms, advantages of the new system from the economic point of view. 
To begin with, a brief outline of the principal changes in instrumentation 
needs to be stated, so that the transformation can be viewed in proper perspec- 
tive. Prior to instituting the new system, the Geological Survey operated some 
350 Multiplex plotting units, utilizing some 800 Multiplex projectors, including 
those used in bridging. In addition, 69 Kelsh plotter units and 9 heavy plotter 
units were in operation. Under the new system, the Multiplex projectors are 
being replaced by ER-55 projectors, to be used principally with twin low- 
oblique photography. Also, Twinplex plotters are being installed for aerotri- 
angulation of twin low-oblique photography. Because of increased efficiency 
resulting from the new techniques and instrumentation, the planned replace- 
ment rate is 2 units of ER-55 equipment for 3 units of Multiplex equipment; 
* This paper is a contribution to Commission IV of the International Society of Photogram- 
metry. 
tPublication authorized by Director, U. S. Geological Survey. 
U.S.A.-1