Which of the following is/are correct statement$\text{(s)}$?

1. Back Bearing of a line is equal to Fore Bearing $\pm 180^{\circ}$
2. If the whole circle bearing of a line is $270^{\circ}$, its reduced bearing is $90^{\circ} \text{NW}$
3. The boundary of water of a calm water pond will represent contour line
4. In the case of fixed hair stadia tachometry, the staff intercept will be larger, when the staff is held nearer to the observation point