The procedure is as follows.
A) CENTERING THE TOTAL STATION: The instrument must be vertically above the survey station to ensure that horizontal angle observations are correct. The steps are as follows:
i) Start with a instrument to get it approximately right above the survey station.
ii) Move the foot of tripod so that the optical plummet cross hairs are on to the survey station.
iii) Roughly level the instrument using the legs of the tripod the total station should stay almost on target.
B) LEVELLING THE TOTAL STATION
i) Turn bubble parallel to two foot screws, to bring the horizontal bubble to the centre of its run by moving the foot screws in opposite directions (the bubble moves in the direction of your left thumb).
ii) Turn the instrument through 90º and bring the bubble to the centre of its run by adjusting the third foot screw only.
iii)Turn the instrument through a further 90º to check the adjustment of the plate bubble.
iv) If the bubble remains in centre, then it is in adjusted position .
v) If not, move it back one-half of the movement from the centre and re-adjust for a further 90º turn.
vi) Repeat the whole procedure; assuming this is the correct, the bubble will stay in a stationary position.
vii) The bubble must remain in the same place in the tube during a 360º rotation of the instrument.
viii) If the stationary position of the bubble is still off the centre, then a permanent adjustment should be made.
C) TRAVERSE FIELD WORK
Traversing is carried out with three(3) tripod, one(1)tripod is for the instrument and the other two(2) are for the back and front stations. A minimum of three people are required in a traversing team. The leader of the team performs setting up and reads the instrument, while the 2nd person has the important job of recording the readings on the booking sheet.
The 3rd person has the task of moving and setting up the prism as the traverse progresses.
There are several steps which should be followed that will lead to a smooth traverse.
i) Traverse stations are established at the proposed site (say) (peg 1, peg 2, peg 3 & peg 4 etc).
ii) The total station is plumbed over peg 1 and accurately levelled. Prisms are plumbed over peg 2 & 4.
iii) Take bearing of first line by bisecting prism at peg 2.
iv) Sight the prism at peg 4.Measure the distance between peg 4 and peg 1. Set the instrument to zero. Rotate the instrument and bisect prism at peg 2.Vertical and horizontal angles are displayed in relation to peg 4. The reading is taken and entered in the field book.
Distance between peg 1 and 2 also measured with the same technique.
v) Record face left horizontal angle reading .
vi) Transit the instrument to change to the face right setting.
vii) Record face right horizontal angle by same procedure.
viii) The total station is moved to peg 2. Prisms are plumbed over peg 1 and 3. Horizontal distances and angles are measured and recorded similarly.