(356) 
The Italian EIRA reports approximate scale and absolute orientation by 
estimation and then refinement of scale and absolute orientation by calcula- 
uon. The USA speaks of impirical methods; Canada says that with the multi- 
plex the absolute orientation is simultaneously obtained of a few models, the 
number depending on the contour interval The Swiss report a graphic 
method; in case of a superabundance of vertical control the deformations of 
the model are adjusted by the Bachmann method. 
In France, both for the first model and for a model oriented in a “bridge” 
after a model already plotted, a proportional projection method is used, con- 
sidering discrepancies in passpoints lying on perpendiculars to the base at the 
two nadirs, computing the adjustments as if the passpoints fell in ideal loca- 
tions; the graph of the projection is made in every case. Sometimes a second 
approximation is necessary for the first model and practically never for a 
model of the bridge. The IGM of Brussels uses similar methods. 
Plotting Apparatus. 
Two classes can be distinguished. 
l. Universal plotters, already known, resolving completely the plotting pro- 
blems, of which only more recent models presenting few changes from the 
former have appeared. 
2. Simplified apparatus, which in general, regard as zero some parameters of 
orientation and in consequence give only an incomplete and inexact plot. 
In the first class, the Stereotopographe Poivilliers, the French IGN uses 4 
types A, B, C, D; the French Cadastral Service uses type B; the IGM of Brus- 
sels uses types B and D; the USA uses types B & C for experimental work. 
The Wild Autographs are used in Canada Types A5 and A6; in Sweden 
types A5 and A6 and one A7 to be delivered in 1952; in Netherlands, type A6; 
A5, A6, and A7 in USA, in Public Works and IGM at Brussels A5 and A6 and 
in Switzerland A2 and A5. 
The Wild firm will offer two new types: the A7 to replace the A5 and the 
A8 to replace the A6. 
The Stereocartographes Santoni exist in 3 models: III and IV and Stereo- 
simplex Model II. The Model IV is used in the USA for practical studies, in 
Belgium by the Ministry of Public Works and the IGM. The Italian IGM still 
uses the old Model II but mostly Models IIT and IV; the E.LR.A. uses Models 
III and IV also the Stereosimplex II. 
The Nistri Photostereographs have been in use for many years, but in 
1951 M. Nistri has made a stereoscopic type and in 1952 a type which, like 
earlier models, uses direct double projection. 
The Zeiss Stereoplanigraph is used in Finland, Sweden, Austria, U.S.A., 
Belgian Public Works and Switzerland. In general these are older types, the 
most recent being the C5. Since 1951 Zeiss Opton at Oberkochen has built the 
Stereoplanigraph C8 which has a format 23 X 23 cm. 
The Multiplex apparatus has been constructed in different versions in 
several countries: 
Multiplex Zeiss, Nistri, Bausch and Lomb, Williamson. 
The Zeiss Multiplex has not been constructed since 1945. 
It 1s still used in Sweden. 
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