The Back Bearing measures the absolute (compass) angle to the previous station. Several formats are supported. See Traverse Entry Options dialog for more information on angle formats.
Note: this angle is measured in the same sense as the Foreshot e.g. if the Foreshot was N (due North) the Backshot should be approximately S (due South). See also Foreshot/Backshot dialog.
The Fore Bearing and Back Bearing are averaged to calculate the coordinate of the next station.
It is also possible to change absolute angles to turning angles to minimize the influence of local magnetic attractors. See Magnetic Anomalies for more information.