î 
8 
AY, A Z, calculated for each point observed by comparing the coordi 
nates obtained through aerotriangulation with the coordinates determined 
with the classical topography systems. At the foot of each plate we 
showed the general planimetry of the points examined. 
To facilitate the comparative examination of the various differences 
AX, A Y, A Z we traced, for each coordinate, the correction curve 
relating to the strip axis, defined approximately by the line linking 
together the control points included in the central area. Furthermore, in 
correspondence to the axis itself, we transferred the two adjusting curves 
relative to linear and square adjustment of the closing errors found out 
between the extreme central points. 
5. It is interesting to note, after a first brief qualitative examination 
of the work, that any residuate errors consequent to the linear and 
quadratic adjustments show in all tests some uniform characters. Gene 
rally the adjustment by means of a second order curve seems the best 
suited to reduce most of the errors, particularly those concerning the 
two X and Y coordinates. 
Doubtless this similarity between different curves represents the 
most important element in favour of carrying out analogical aerial trian 
gulations with Stereosimplex III, whether or not provided with a con 
trol device. It proves in fact that this instrument may safely be employed 
in such type of work the same as any other universal type stereo 
plotter (8). Of course aerotriangulation will have to be carried out fol 
lowing the most suitable systems, including that of limiting its length 
according to the precision one wishes to attain. 
For experimental conditions we can further note that the use of 
the control device of parameters w, ? and x is particularly suited for 
eliminating any reading and adjustment errors, which are so frequent 
when the same parameters are simply transferred by a visual method. 
Amongst other things, experience acquired has shown that the use of 
the device in question does not noticeably increase the cost of work. 
Anyhow, the intervention of the control device also seems to be 
able to reduce the differences in the closing error of strips, as happened 
for instance in test B. Here in fact the differences at the happened 
points had a quite peculiar tendency, specially as far as coordinate Z