Fig. 4. Balplex Plotter. The equipment gives good survey over large areas and 
sufficient accuracy in the preliminary planning stage. 
orientation of the models in the instrument the drawing board is raised 
to what 1s roughly the models' median height with the help of a hydrau- 
lic lifting device. In the models the road-line is marked in on sketching 
paper. It is very easy in the total model to assess the practicability of 
the terrain in the vertical plane on broad lines, and detail information 
concerning conditions on the vertical plane is obtained direct through 
altitude measurements with the tracing table, the drawing table being 
in this connection lowered to rest in its normal position on its dowels. 
Through this alternation of work on the one hand in the whole model 
and on the other hand with the tracing table one has excellent possibili- 
ties of fitting the road-line into the terrain horizontally and in profile. 
The purely aesthetic considerations can also be effectively met when 
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