local cartography of the municipality near the quarry: in
this case they have to be propagated using the traditional
topographic methodology, that’s to say the geometric
levelling or the trigonometric one.
Fig. 1 The GPS fundamental network
To test the results of the Est-North co-ordinates of the
vertices of the quarry with the GPS approach, these co
ordinates are 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 Cernusco
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 of 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 of Desio, Usmate, Melzo and S. Donato
Milanese are GPS points surveyed near to the IGM
levelling benchmark and connected to them through the
Fig. 4 The first order network of the quarry of Peschiera
Borromeo (Milan) and the primary vertexes
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
Fig. 5 The detail vertexes connected to first order
network of the quarry of Cernusco sul Naviglio (Milan)
necessary at least 3 points around the area.
For each quarry it has been surveyed a local network:
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