For example, the fixing on the instrument photographic plates 
23 X 23 cm. taken by cameras of 15 cms of focal distance, it is 
possible to reconstruct an optical model at a scale almost three 
times larger. If photograms of smaller size and taken with shorter 
focal distance are used the magnification can be increased. 
The long runs of the coordinatograph do not require that the 
operator loose time or make excessive effort: the carriages are 
in fact mounted on ball bearings that run on cylindrical rectified 
guides and the operator can move them directly with a minimum 
of effort. For the tracing of planimetry and of contour lines the 
control of the coordinatograph is accomplished by means of a 
reducing pantograph provided with an electromagnetic coupling 
powered by pressing lightly on the handle of the pantograph 
itself. This device which commands the carriages X and Y renders 
particularly easy and rapid the tracing of the contour lines. The 
tracing pencil is placed on another pantograph by t which can be 
drawn maps, magnified or reduced up to three times in respect 
to the optical model with very high precision. 
The drawing table is situated in a very suitable position for the 
operator, who can control the lowering of the pencil other tha n 
directly by hand due to his proximity, also with a pedal control 
switch. 
In all the particulars of design and realization the concept of 
the designer is rivealed: obtaining the maximum efficiency well at 
same time not loosing the slightest degree of accuracy.