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Fig. 8 - The prospective plotting of the outisde Dome of Santa Maria del Fiore in Florence 
The problem was resolved, in the survey of the dome of Santa Maria 
del Fiore (1), taking as comparative elements the floor level inside the 
dome (X, Y plane) and the average axis of the dome itself (Z axis). 
For the later analytical processing, these coordinates X, Y, Z have been 
then immediately transferred in cylindrical coordinates Z, R, the refe- 
rence always being the inside floor level and the average axis of 
symmetry above said. 
As was amply demonstrated in the technical report on the survey of 
the same dome (1), the numeric plotting of an architectural structure 
presents the great advantage of allowing a more thorough analysis 
of the monument in question. The reliability of the numerical results 
can be better illustrated if accompanied by similar considerations of a 
graphic nature. 
It is in any case advisable to split up the plotting operations into 
separate and successive phases. 
Once the optical model is obtained, in the first phase it is preferable 
to proceede to the graphic representation in scale of the structure which 
is the object of the survey. In later phases the numerical plottings of 
the structural elements of greater interest will be calculated. 
Plotting of painted surfaces can be easily accomplished with orto- 
photography techniques. An experiment made in this regard with the