corrective plat Th 
° with a new and di, 
they had à distorty 
ntage is achieved hat 
hotographs, Somethy, 
rately by indepengyy 
)ptieal SyStem, as gy, 
; Since the use of y 
ne of which can sere 
loing photogrammer; 
1 the advantage of i 
the Porro-Koppe yn. 
lems noted previos; 
of the photograph 
> characteristics ip 
ew camera of diff 
. This plotter hope 
understood. Now, ii; 
, Dr. Gino Parent] a 
served attention on fi 
with it, to attain fh 
ie most interest — qj 
echanical transmissin 
f the structure of f 
jS in their practical x 
sunderstood intolerant, 
sators and designers! 
must be attributed fia 
the perfect and seer: 
wing. | 
‚ed is a known one, al 
of transmitting angılı 
ons that in some ds 
| a few seconds dt 
tters. 
| such a way that u 
illimeter of the mari : 
responding to the s 
that when this nia 
t employable in phi 
about a want of 
vices, so that the p 
e mark by à tenth 0 
d in the plotter 54 
nt of phase betwedt Ef s 
ave a torque of i 
rcome the inertia € : 
he mark and the "m 
- to the postion à * 
  
Lark comes about with an Roproximation higher than a hundredth 
he hand moving on the dial opposes practically no resistance, 
cause t e approximations, therefore, are largely contained within the limits that are 
Tre the play in the mechanical linkages, with a benefit in favor of the electro- 
a tic transmissions deriving from an elasticity in practical use that protects the 
idi i t from the consequences of any lack of attention. 
eo nnanetic transmissions also, because of the wa 
heen i for the Photostereograph and, generally, for al 
mmunication between the mark and the pencil even in t 
i axes (since two or more electro-coordinatographs c 
m to trace maps with different denominators) 
ay reason whatsoever. In such a case, the electro-magnetic device, which is linked up 
vith the shaft whose operation is impeded, creates in the others a torque that is similar 
hut contrary to that which tends to make them revolve, the which, in this case, comes 
from the device controlled by the handwheel, so that they all stop at the Same time, 
The simplicity of these transmissions and the way in which they react ha 
me to apply them also to my plotters based on the direct optical 
the Photomultiplex D-III and the Photocartograph model V. 
exploration of the model controlling the mark with the system used in the large plotters, 
and permitted the ability to compile maps on any scale whatsoever, thus freeing these 
plotters from the necessity of the following scale transformation of the compilation and 
from the limitations of the altitude at which the exposures are made. 
The advantages of the electro-magnetic transmissions are not limited purely and 
simply to the replacement of the mechanical transmissions, but they have also permitted 
the use of a “steering” device, that is to say a single handwheel controling the move- 
ment of the mark on the datum plane, this being in a certain sense something like stee- 
mg a car. This device, which frees the operator from the uncomfortable and tiring 
vorking of the handwheels, the accepted practice today, is destined to revolutionize the 
we of photogrammetric plotters, simplifying their technique, lightening the effort and 
thus increasing the output. The Veltropolo, as this dévice has been named, is standard 
equipment on all the plotters I have presented to this Congress. 
In finishing, I feel it is opportune to re 
(uted, as published in the Cadastre Review, 
influences of instrument developments in the 
dear and suecinet expression: 
"The precision of a plotter is only in part based upon the accu 
construction, the which, when certain limits are passed 
regard to the cost of the instrument and to the servit 
of the kinematic parts, maintenance and the precaution 
"It is therefore the principle on which the instru: 
io limit these drawbacks, because the less it relies 
ae the chances to obtain greater precision in practi 
“As for the way to test the precision of photogr 
lest by plotting the grids is the best way, 
of a millimeter be- 
y in which they have 
1 my plotters, guarantee 
he event that one of the 
an be used at the same 
stops in the course of operations for 
S induced 
projection principle, as 
This has permitted the 
peat the conclusions in the article already 
because there my ideas about the economic 
practical pursuit of photogrammetry find 
racy of its mechanical 
, 18 a negative element both with 
ude it exacts by way of the wear 
S necessary in using it. 
nent is based that must intervene 
on accuracy in its design, the greater 
cal use. 
ammetric plotters, needless to say the 
because only so are we freed from the other 
ses of error implicit in the whole air survey project. It is well to note however that 
the final approximation of a survey derives from just such a complex of causes, which 
* Will more properly call photogrammetric ones, which run from the approximation, 
With Which the interior orientations of the take and plotter cameras correspond, to the 
Searing which the image suffers in that brief moment that the shutter remains open, 
ny ef the aireraft's Speed; from the emulsion grain to the care used in processing 
* film; from the characteristics of the terrain photographed to the shadows produced 
n tlt of the sun's rays; from the deformations to which the film is subject above all 
(Me various phases of the take to its use in the plotter. 
7