ais eee er re 
  
8. Computation of mass diagram, including compaction 
factor, giving summary of earthwork operations 
and costs. These design data are printed out in 
tabular form suitable for inclusion in final 
plans (Figure 4). 
The computer can, of course, be used in other parts of the 
total highway design effort such as: 
9. Bridge and structure design computations. 
10. Drainage areas and culvert sizes. 
11. Accounting, inventory, and payroll. 
There are also additional applications of the aerial 
photographs in the highway design effort. Among these are: 
1, Soil mapping showing type of stratification, ul 
location of rock outcrops, overburden conditions, | 
marsh, swamp, and areas of poor vertical drainage, 
2. Delineation of drainage network and drainage areas. bli 
3. Base sheet for property acquisition negotiations. 
A flow diagram for a completely integrated photogrammetric- 
electronic highway design system is given in Figure 5. 
  
ACCURACY 
The photogrammetric-electronic highway design system has | 
not been in operation long enough for all engineers and con- bi 
tractors to accept it as a replacement for conventional methods. 
Specifications for vertical accuracy of photogrammetric 
maps usually read "Ninety per cent of all elevations shall be IT I 
correct within one-half a contour interval." A map can meet Wl 
this specification and still contain a systematic error of bl 
almost one-half contour interval, Unfortunately such systematic 
errors are almost inherent in the photogrammetric process, For 
this reason, it may be justified to view with a suspicious eye Un 
the final earthwork quantities obtained in such short time and 
with such apparent ease. 
  
A definitive series of tests was conducted by the California 
Highway Department and reported by L. L. Funk in Bulletin 228 
of the Highway Research Board. The essential features of these | 
tests were: M