Traverse Line Bearing Difference Explained
Fore Bearing (FB) is the bearing measured from the starting point towards the end point of a traverse line.
Back Bearing (BB) is the bearing measured from the end point back towards the starting point of the same traverse line.
Both bearings are measured with respect to the same meridian (North or South line).
Bearing Relationship
The Back Bearing is exactly $180^\circ$ opposite to the Fore Bearing. This relationship holds true regardless of whether the bearings are true, magnetic, or assumed.
The mathematical relationship is:
$BB = FB + 180°$ (if FB is less than 180°)
$BB = FB - 180°$ (if FB is greater than 180°)
Therefore, the difference between the Fore Bearing and the Back Bearing is always exactly $180^\circ$.
Correct Answer: Option C (exactly $180^\circ$)
Important Questions from Traversing
- The forebearing of four sides of a closed quadrilateral ABCDA are
AB = 60°, BC = 149.87°, CD = 269.5°, DA = 20.17°.
The calculated value of interior angle D is _____° (Answer in decimal degrees and rounded off to two decimal values). The angular misclosure of the closed-loop traverse shown in the figure is _____________ ° (Answer in decimal degrees and rounded off to three decimal places)
- It is needed to establish the coordinates of a station A. Two stations B and C are available whose coordinates are given in the table.
Length of line CA = 1212.38 m; ∠BCA = 64°.
The Easting of station A is _______ m (Rounded off to two decimal places).
Assume station A lies to the west of the traverse line BC.Station Easting (m) Northing (m) B 11054.09 9484.37 C 10827.62 10112.15 - If the departure and latitude of a line are 70 m and -130 m, respectively, then the whole circle bearing of the line in degrees is
While carrying out a traverse survey ABCDA' using a theodolite with the originating station A, the departures and latitudes of the lines, as obtained, are shown in the following figure (not drawn to scale). It is seen that, due to the observational errors, the originating station A and its computed station A' are not the same. For this survey, the 'closing error' in m is
