Errors due to wind: Strong wind disturbs leveling of an instrument and verticality of staff. Thus, it is advisable to suspend the work in this condition. Errors due to sun : Due to bright sunshine on the objective, staff reading cannot be taken properly. To avoid such error, it is recommended to maintain a shed to the objective. Errors due to temperature: Temperature of the atmosphere disturbs setting of parts of instrument as well as causes fluctuation in the refraction of the intervening medium. These lead to error in staff reading. Disturbance caused to instrument may be minimized by placing the instrument under shed. |