You may wish to delete all underway data. One possible reason for this is a lack of Ashtech heading corrections. If you only have gyro data, you may only trust on-station data. This is an artificial example, but shows the effect of lowering the default cutoff for deleteing underway data from 100m/s to 6.5m/s:


100m/s is "underway"
(i.e. flag nothing as underway)

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6.5m/s is "underway"
(i.e. flag some as underway)

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