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Figure 8-14: Plot Two - Vector Averaged and Scaled
The vector averaging approach produces an acceptably accurate result and is easily
implemented with either field or spin test data. The vector can be hand calculated if necessary.
The numerical results in this example, which can be applied to other portions of the data from that
compass, are:
X
O
= +0.018 Y
O
= -0.047
X
S
= +0.347 Y
S
= +0.338
Note that to produce a good vector average, the original measurements must be
approximately evenly spaced in angle (keep this limitation in mind if you use this method with
field data). Each quadrant will produce different numbers of measurements and representative
values will have to be chosen manually for even coverage. It is also necessary to have
measurements near to the north, east, south, and west directions so that the two scale factors can
be calculated.
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