in 
1e 
LS 
  
  
23. 
the profile. It is also obvious that instead of graphical,a numerical recording 
system could be used. 
In the actual test a large number of automatic parallel profiles were 
produced with graphical recording. 
Planimetric Plotting 
Although the automatic stereoplotting device can determine x- and y- 
parallaxes and can use these for various automatic operations, it cannot perform 
any kind of interpretation and therefore no automatic plotting of planimetric detail. 
However, the device may be used to keep track of elevations while a human opera- 
tor performs the planimetric plotting. This will lessen the strain on the operator 
and should permit a faster plotting speed and probably, improved accuracy. 
During the experiments covered by this report some planimetric plot- 
ting was also carried out. It was found that in its present form the automatic 
stereoplotting device is rather awkward for this purpose. This is due to several 
factors. Firstly, because the scanning pattern and the anaglyphic stereo image 
are superimposed on the surface of the scanning head, the action of the bright scan- 
ning spot interferes unfavorably in visual observations. This interference may be 
somewhat reduced by stopping the motion of the dot so that the device will be in 
sporadic operation, although this will be disturbing for the operator. 
Secondly, there appears to be a clear systematic difference between 
the elevation perception of a human operator and of the automatic stereoplotting 
device. Therefore, when the elevation determination is under the control of the 
automatic device the operator sees the dot about 0. 8mm below the ground in the 
model scale, and this impairs the plotting results. 
Thirdly, the servomechanismthat drives the plotting apparatus introduces 
considerable friction that makes the manual control of the tracing table jerky and 
inaccurate. 
The fact that the automatic stereoplotting device in its present form 
was not very helpful in planimetric plotting does not mean that the device has 
no potential in this field. On the contrary, all the unfavorable factors mentioned 
above may be overcome relatively easily, particularly if the device should be 
installed on a different type of plotter. 
CONCLUSIONS 
There is no doubt that the device tested presents the first and most 
successful attempt towards automatic stereoplotting. This achievement is particu- 
larly remarkable in view of the fact that the anaglyphic type of plotter to which the 
device was adapted has basic drawbacks and shortcomings. Limited light energy 
supplied by the projection system is a serious limitation that has direct bearing 
on the accuracy and speed of automatic operations. Additional serious limitations 
are caused by the appreciable mass of the movable tracing table and scanning 
components and by the distance these components must travel during plotting. An 
adaptation of the present device to a plotter that can offer more light energy,