4 — Photogrammetric activity of the Italian Cadastral Survey 
The Administration of the Italian Cadastral Survey has at its disposal 
a plotting laboratory and makes use also of plotting apparatuses owned by 
Institutes of Engineering. 
The major part of work, however, is leased out to private firms, which — 
excepting the photographic flight — carry out all operations needed from the 
demarcation of landed properties to the final design of the map. 
The maps accepted by the Administration after being tested, are paid 
at the rate of an unit price (per 1 ha), which varies slightly according to par- 
celling and to the topographic features of the zone as well as to the map scale. 
Photographic flight is carried out by the Military Geographical Institute or 
by specialized companies. 
The total expense of an air survey is variable and depends upon the scale 
of mapping and amounts for the Administration to the same sum which would 
have to be paid for the same survey carried out by means of classical terres- 
trial methods (tacheometric survey). It must be kept present, of course, that 
with the classical methods only planimetry is obtained, whereas — at the same 
cost — air survey methods furnish also contours. 
On the other hand, if the case my be, contour lines and spot heights are 
not required, the cost of an air survey will be inferior by 3095 as compared 
with ground survey for maps on scale 1 : 4000 and diminishes with the incre- 
ase of the scale. This is obvious, as in large parcelled areas to be plotted on 
scale 1:4000, contours weigh heavily on the total cost of the map, whereas 
for small parcelled areas to be mapped on scales 1 : 2000, 1 : 1000 or 1 : 500, 
the major part of cost must be referred to planimetry, plotting of contours 
and spot heights being complementary, and therefore comparatively cheap. 
Italian Air Survey Companies use Italian deviced and built apparatuses, 
such as the Photocartograph Nistri, the Stereocartograph Santoni and the Ste- 
reosurveyor IRTA. 
All technical and contract regulations for leasing out air survey are col- 
lected in a special scheme, which is continuously improved on the base of 
results of the latest experience, thus determining in every detail the relation- 
ship between the Administration and the Air Survey Companies. 
In the contract, besides the general condition and the responsibility of 
the lessee towards the Administration and towards third persons, the price to 
be paid per 1 ha mapped, the time of delivery, penality for exceeding the time 
limit, penality for gross errors ascertained in the planimetric and altimetric 
design, are regulated. 
The conditions of the contract, apart from determining the operations of 
purely cadastral survey (plotting of limits of landed property, administrative 
questions, etc.) refers also to the trigonometric operations for determining the 
points of minor control and to completion on the ground (geodetic and topo- 
graphic regulations). Further it refers to all operations concerning the marking 
of ground before the photographic flight as well as the office operations