least-square adjustment in a survey network allows for the computation of a single solution for each
station and minimizes the corrections made to the field observations. A least-square adjustment uses
probability in determining the values for particular unknowns, independently weighs all field
observations, highlights large errors and blunders that were overlooked before adjustment, and generates
information for analysis after the adjustment (including estimates of the precision of its solutions).
f. Traverses. Traverse is the measurement of lengths and the determination of directions of a series
of lines between known points. They establish the coordinates of the intermediate points. When
computed, the accumulated closing error shows up as a position displacement of a known point. The
displacement is corrected and distributed among the intermediate (traverse) points.
g. Elevations. Depending on the purpose, the elevations on some level lines are computed as the
measurements are taken. When the line is closed, the difference in elevation (DE) between the
measured and the known elevation is adjusted over all the stations in the line. In higher-order leveling,
only the differences in elevation are recorded during the measuring, and all adjusting is done at the
completion of the line. The error is then distributed among the various sections of the line.
2-26. Establishing Records. Office computations reduce the field notes to a tabular or graphic form.
They become a permanent record and are stored for further use or subsequent operations. Many
standardized forms are available and should be used. As long as the sheets are clearly identified and
bound as a set, they are acceptable. Normally, all field notes should be abstracted and filed separately.
The abstracts should be bound along with all computing forms into a single binder or folder and
maintained on file for further reference. All pages should have the name and date of the person
performing the work and at least one person who verified that page. Do not dispose of or destroy any of
these records.
2-27. Performing Checks. Surveying involves a series of checks. The observer, the recorder, and the
party chief should check the field notes before they are turned in for office work. Before computing, the
assigned person should check the notes again. Most mathematical problems can be solved by more than
one method. When checking a set of computations, it may be desirable to use a method that differs from
the original computation method. An inverse solution (starting with the computed values and solving
for the field data) or a graphic solution may be used. Each step that cannot be checked by any other
means must be checked by a totally independent recomputation by another individual. Any errors or
mistakes that are found must be resolved and rechecked before the computation is accepted.
2-15
EN0593
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