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General Principles for Traverse Processing
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These comments apply to all forms of normal traverse reduction,
i.e. total station derived data files or manually-entered traverse
data, but not when the LS-Network adjustment mode is
used.
However, all traverse or network observations entered
through the Traverse option or
data files processed by the e-Data
option, may be initially subject to an analysis and optimisation
process depending on the setting of the Mean Control
Observations check-box in each of these options. (For more
detail refer to the section Meaning and sorting traverse
observations in the Traverse
topic, and to Meaning, sorting and correction of control,
traverse and network observations in the Extract file topic). All other
normal traverse processing in each of these options is performed by
the same software procedures regardless of the menu option
in use.
- A traverse may consist of any combination of lines, provided
that all are entered (manual traverse) or as-surveyed (total
station derived) in a correct, logical sequence except that
any side-shots must precede observations to the next traverse
point. Refer to Traverse
Types for diagrams of possible traverse configurations.
- Pure triangulation or trilateration (angles or distances) can
be processed only if traverse data is to be computed and adjusted
by the LS Network (least-squares) option
- Refer to Extract file
for discussion of the means by which traverse observations may be
re-ordered into correct sequence when necessary
- Refer to Network
Adjustment - Least Squares for discussion of adjusting
traverse or network data by the Least-Squares Network
option
- Any number of side-shots may be observed from any particular
traverse station (including the observation to the next traverse
station)
- Where Bowditch adjustment is to be performed, any
traverse section that closes onto a previously-defined fixed point
will be adjusted before calculation continues onto the next
traverse section
- When more than one foresight point is observed at any
particular station, the last observed point in a set will
generally be the next setup station in a traverse. However, if
any of the side-shot points happens to be a fixed control
point or a point held fixed on a previous traverse section during
the current run, then the current traverse section will be closed
(and adjusted) at that point (refer to previous point above) and a
new traverse section will commence from the next observed point in
the set
- Any number of closed and un-closed traverse sections may be
combined into the same processing run
- If the start point for any traverse section has never had a
valid height value assigned to it (i.e. it is blank), then any
vertical components computed will not be carried through and all
points will be given null heights
- Traverse adjustment is by error distribution amongst horizontal
angles (where applicable) followed by Bowditch (also known as
Compass rule) adjustment of coordinates; where appropriate
- Vertical traverse misclose is adjusted by simple distance
proportion. Refer to Vertical Adjustment for
further information
NOTE - The traverse None or
Bowditch adjustment modes should only be used to test
closure accuracies or to provisionally coordinate points prior to
adjusting the same data with the LS Network mode. The least
squares method gives a far more reliable and mathematically sound
adjustment, the summary contains considerably more detail, and will
be found to have greater industry acceptance of the statistical
reporting of the adjustment. |
For further details: