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compared with the relative position (distance and difference of 
level) of the same vertexes using traditional instruments. The 
tolerance between the distance and the difference of level 
evaluated from the Est-North co-ordinates and trough 
traditional instrumentation must satisfy the tolerance of 5cm 
(distance) and 8cm (difference of level). 
Fig. 2 The first order network of the quarry of Cemusco sul 
Naviglio (Milan) and the primary vertexes 
The determination of the fixed vertexes of the so called 
fundamental network must be carried out only once for each 
quarry. The vertexes of the Network must be well maintained. 
Only trough the conservation during the time of the 
referrement vertexes is possible to assure a valuable and 
reliable estimation of the volume of the extractive activity. 
Fig. 3 The first order network of the quarry of Verano Brianza 
(Milan) and the primary vertexes 
The georeferentiation of the primary vertexes ol the network, 
in the three case-studio quarry, has been obtained using one 
benchmark of the IGM95 (zero order GPS Italian Network) 
centrally positioned respect to the fundamental GPS network. 
The vertexes localized in the Municipalities ol Desio, Usmate, 
Melzo and S. Donato Milanese are GPS points surveyed near 
to the IGM levelling benchmark and connected to them 
through the 
levelling. The WGS84 datum has been rotated and translated 
using the parameters of the point IGM95 (three translations, 
three rotations and one scale factor. 
The Orthometric heights of the points are derived through the 
estimation of the Geoid undulation with respect to the WGS84 
ellipsoid in the points where both the Othometric height and 
the ellipsoidic one are known: in this case are necessary at 
least 3 points around the area. 
Fig. 5 The detail vertexes comiected to first order network of 
the quarry of Cemusco sul Naviglio (Milan)