Fig. 6. Stereoautograph Wild A 8. This type of equipment is well suitable for the 
detail work that is needed for road planning. 
The pictures and the instrument used for their treatment afford an 
accuracy with a standard error in the horizontal and vertical planes of 
less than = 0.5 m, which for the purposes of the preliminary planning 
at this stage 1s sufficient. 
[Field investigations of doubtful parts of the proposed roadlines are 
then undertaken and the economic and traffic technical calculations on 
which a final decision in favour of the one or the other alternative must 
be based are studied. With the help of the data-machine it is possible 
to get a quick preliminary notion of the respective earth quantities and 
construction costs for the alternatives. When the solution to be preferr- 
ed has in this way been ascertained a complete map on the scale of 
1:2000 is drawn with contours of 1 m equidistance over an area of 200 
9 
  
  
  
—D———————À—Ó———