Explanation: In trans versing by direct observation of angles, angles between the lines are directly measured by a theodolite. The method is therefore accurate in comparison to the previous three methods.

Explanation: The magnetic bearings of any one line can be measured and magnetic bearing of other lines can be calculated. The angles measured at different stations may be either included angle and deflection angle.

Explanation: Transversing by included angles and transversing by deflection angles comes under transversing by direct observation of angles.

Explanation: An included angle at a station is either of the two angles formed by the two survey lines meeting there. The method consists simply in measuring each angle directly from a backsight on the preceding station.

Explanation: Included angles can be measured either clockwise or counterclockwise. But it is better to measure all angles clockwise.

Explanation: It is better to measure included angles clockwise. It is because of graduations of theodolite circle increase in this direction.

Explanation: A deflection angle is an angle in which a survey line makes with the prolongation of the preceding line.

Explanation: Transversing by deflection angles is more suitable for surveys of roads railways, pipe lines etc, where the survey lines make small deflection angles.

Explanation: A deflection angle is an angle in which a survey line makes with the prolongation of the preceding line. It may vary from 0° to 180°.

Explanation: The deflection angle at Q is alpha R and that at R is teta L.