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program utilizes the profile data which was punched on tape during 
the previous operation. It also requires an input tape which defines 
the desired elevation and path for the proposed highway. Given this 
information, the computer calculates the area of each cross section 
along the highway and determines the volume of earth which either 
must be removed or added along that section. Operating as an X-Y 
plotter, the AP-C system could be used to plot cross-sections and 
profiles from highway and terrain data at the same time that the cut- 
and-fill calculations are being performed. 
CONCLUSION 
The AP-C Analytical Stereoplotter consists of a viewing unit, a 
coordinatograph, and a computer, which are electrically connected to 
gether and programmed to operate as a precision photogrammetric 
instrument. In addition to the usual functions of a stereoplotter, the 
instrument can be used as an X-Y plotter or as a stereo comparator 
with existing computer programs. The computer can also be 
programmed to provide auxiliary functions as simple as computing 
areas or as complex as analytical aerial triangulation and block 
adjustment. The examples cited in the preceding sections are only 
typical of many applications which may be found in general mapping 
and surveying operations as experience with the AP-C system is 
accumulated.