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Sharing and cooperation in geo-information technology
Aziz, T. Lukman

For each quarry it has been surveyed a local network:
1.1.2 The georeferentiation of the detail vertexes
The georeferentiation of the detail vertices is obtained respect
to the vertexes of the fixed GPS network described upper. On
these secondary vertices it is possible to make station with the
topographic instruments for the detail measurements. The
vertexes of the detail network, propagated from the primary
vertexes, can be materialized through quick modalities. These
vertices can be easily repositioned and the position can be
calculated ex novo from the primary vertexes; the primary
vertexes have to be positioned where is non prevented the
activity of extraction, perhaps around the limits of the quarry.
The connection of the local GPS network with the Gauss-
Boaga system has been obtained connecting one or more points
to one IGM95 vertices and to two altimetric points belonging
to the fundamental network.
All these measurements of the three local network has been
processed together by least square adjustment.
1.2 The Survey of the detail
The second phase of surveying is the survey of the details. In
function of the typologies of the quarries the instrumentation to
support the survey detail has been chosen: two are the
methodologies that can be adopted in function of the different
typologies of the quarries.
For the under water quarries (quarry at the ground water table
and at the stratum superficial) it has been used a GPS (RTK
modality) associated to an echo-sounder, for the open quarries
it has been used a total station motorized no prism.
We have to remember that this survey is finalized to the
estimation of the volume of the area of extraction and to the
building of a DTM which have to satisfy the characteristics of
the precision for this work.
The survey of the detail has to be integrated with further
information about the characteristic elements of a quarry, such
as the position of the electric network, buildings, and other
which allow to better represent the quarry.
Two are the methodologies that can be adopted in function of
the different typologies of the quarries.
1.2.1 Open quarry
The instrumental characteristics. To survey sectors of the open
quarries is suggested to adopt a total station motorized no
prism positioned on the vertexes used for the georeferentiation
or for the vertexes of integration. This kind of advanced
instrumentation has impulse laser range finder that allows to
measure the distance, without prism, of many hundred of
meters using the natural surfaces like reflective surfaces. With
these instruments is possible to improve the accuracy of the
volume estimation thanks to the points density that can be
obtained with the automatic modality and determining
homogeneous areas inside which the terrain is scanned. These
total station motorized can survey some thousands of points per
hour. The data surveyed (azimuth, zenith directions and
distance). Data are registered on file ASCII.
Generally the open quarries are characterised by fronts with
steep slope.
The applications have shown the obvious necessity to acquire,
during the survey, the breakline located in the quarry area.
Consequently is extremely important to realize an higher
density grid of points. Only in this case it can be obtained the
precision necessary to avoid conflicting on the volume
estimation. Also the density of the points has a fundamental
role particularly in the case of irregularly surfaces like it’s the
case of the quarry.
In the following table is shown that assuming as a datum
volume ( the definitive configuration) the one obtained using
all the points surveyed (14929), the percent of error drastically
decrease from a 50x50mt grid to a 5x5m or 2x2m grid.
Fig. 6 The survey of an open quarry with higher concentration of points in correspondence to the change of slope and of steep slope
(Verano Brianza).