Precautions and Errors in Compass Survey:
Precautions
While undertaking the compass traversing, following precautions should normally be observed.
Bearing
If it is difficult to observe the location of the ranging rod at station B from compass set at station A for obtaining the bearing of survey line AB, locate an intermediate station C on line AB, which can be sighted from both stations A and B. The compass could then be set over the intermediate station C. While there is an optical obstruction in the line AB, a parallel line C1 D1 is set out by means of offsets as nearly as possible (Figure (b)) and gets the bearing of the survey line.
(a)
(b) Line Parallel to Survey Line AB
Figure : Bearings when Two Stations are not Intervisible