The network, that covers an area of approx. 60 km 2 , stretches
for around 70 km and is composed of 12 polygons (fig. 2), 10 of
which (from no. 2 to 11) represent the main network and are
used to monitor the areas most closely involved in the CNR-
ENEL project. The network also includes the benchmark of S.
Giuliano Terme, and is characterized by 18 nodes and by
intermediate benchmarks situated at average distance of 500 m.
Figure 2: Levelling network
The other two polygons (no. 1 and no. 12), with a wide mesh,
constitute the connection network between the benchmarks of S.
Giuliano Terme and Migliarino Pisano.
Figure. 3 Closure errors / unit length
Errors of polygon closure have been found from data processing
of the main and connection networks; closure errors are
calculated per unit length, as shown in the diagram of figure 3.
Finally, the mean kilometric error was calculated obtaining
values ranging between 0.2 and 0.8 mm.
3. ADJUSTMENT
In adjustment operations, the main network has been kept
separated from the connection network according to the
criterion which, in the design of the project, led to the
distinguishing in the general network of these two networks
that, while complementary, had different characteristics and
functions.
The operational method used is that of indirect observations and
the results reported in the diagram of figure 4, made it possible
to obtain for s.q.m. a maximum value of ± 2.4 mm and a mean
value of ± 1.9 mm.
