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Settings
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Calculation
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Grid cells
: sees section 7.5.1.6.
As a scan is in progress, collected data is allocated to the grid cells which have been generated.
Each grid cell is allocated the Z value of the lowest point within that cell. This helps to reject spurious points: perhaps
where dust, steam or moving machinery have intercepted the laser.
The user-entered
Angle of repose
(see section 7.5.1.7) is queried and any cells which define a slope beyond this
value are rejected. Again, this helps to reject spurious data from foreign objects in the area of interest. For example
if there is a scoop left in the middle of the pile, or if spurious points are gathered from dust in the air, the surface
formed from these points will have sides that are steeper than the angle of repose and will be discarded.
Any holes in the grid are filled using averaging based on smoothing. Ideally there will be as few holes as possible
in the grid. The main way of ensuring this is through careful positioning of the FiX1.
This finished grid forms the top surface which is then compared to the base surface, to compute a volume.
The final volume consists of:
•
a ‘fill’ volume: the difference between the top surface and base surface in areas where the top surface is
above the base surface.
•
a ‘cut’ volume: difference between the top surface and base surface in areas where the top surface is lower
than the base surface. This will usually be zero as the stockpiled material will be above the floor as defined
in the base surface.
•
a ‘net’ volume: the final result which is the fill volume minus the cut volume.
7.4 Areas of Measurement
The base surface can be sub-divided into smaller regions, with separate volumes reported for each of these regions.
These
Areas of Measurement
may be required if, for example, different grades of material are being stored in
different parts of the same warehouse and volume reports are required for each material.
A PLN file with any number of named polylines enclosing these regions is uploaded to the FiX1 (see section 9.6.2).
The polylines must be located within the bounds of the base surface. Volumes for each named area are displayed
on the PDF report and on the FiX1
Scan list
.
7.5 Hub-and-spoke installations
In a hub-and-spoke installation with multiple units connected to a network, all communications with the installation
is conducted through the FiX1 which has been designated as the hub.
When a scan is activated, the hub sends a scan command to the spokes, together with an empty grid. Each spoke
runs a scan, fills the grid with elevations and returns the grid to the hub. The hub consolidates data from all FiX1
units in the network, cleans the data and computes a single volume (or single set of volumes if different
Areas of
Measurement
are being used) from the resulting grid surface.
7.6 Verification
For verification of the volume, as well as for troubleshooting and QC purposes, data from each scan is available for
download. The main time this is necessary will be during installation and initial system setup and georeferencing.
•
The constructed top surface is available for download as a GRD file. In hub-and-spoke systems, this is
available from the hub.
Summary of Contents for FiX1
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