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SWITZERLAND
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Stateskop RSTS
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b) The RST2 Statoscope, connected to an RC8 Aerial Camera with the
HC1 Horizon Camera.
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Fig.8 a) RST2 seen from above.
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Considerations on plotting from super wide angle photographs
The next question to be answered concerns how super wide angle photographs should be further
utilized when large areas have been covered blockwise by parallel strip photography.
For flat country, mosaics can be prepared using the slotted template or radial triangulation method
with rectified photographs, even for areas with very sparse control. This is done possibly by making
use of horizon camera data which is measured ina micro-stereocomparator (Fig.9). This process is
known, it presents no difficulties and requires no new instruments. On the other hand no satisfactory
plotting instruments were available until recently for stereoscopic plotting from super wide angle
photographs. Instruments with approximate solutions or projection instruments such as the Multiplex
are indeed simple, but unsatisfactory. It was therefore necessary to make decisions on new designs.
The plotting instruments have to perform the task of systematic aerotriangulation coupled with easy
plotting. Earth curvature and atmospheric refraction must be taken into account, and the residual
distortion of the photographic lens must be corrected. The plotting instruments for aerotriangulation
and mapping should be as simple and inexpensive as possible but should nevertheless be based on
the strict geometrical solution. The latter is essential with these large-area models of the super wide
angle photographs, in order to avoid any deformations in passing from one model to the next. Such
deformations appear mainly when inadequate plotters, based on approximate solutions, are used. It
is further to be noted that full use should be made of the picture quality of the photograph, i. e. it should
be possible to identify and interpret all the recorded details with the utmost certainly. This means that
full advantage is taken of the quality of plotter's observing system. It is therefore clear that projection
instruments, with the anaglyph or similar principles, do not come into consideration: the choice falls
on optical viewing which has proved in all large plotters to be the best system so far. Nevertheless, in
order to keep the instruments as low-priced as possible, they must be kept compact in form. This
is not quite so easy in a super wide angle plotter with space rods. For this reason it was decided to
reduce the diapositive to half size in the diapositive printer and to combine at this stage reduction,
elimination of residual distortion and compensation for earth curvature and atmospheric refraction.
In long series of investigations it has been established that by using fine-grain diapositive material