Orientation: The method of setting up the plane table at each of the successive stations parallel to the position it occupied at the starting station is known as orientation.
Orientation by back sighting: Procedure- Ref Fig. bellow
a) Suppose A and B are two stations. The plane table is set up over A. the table is leveled by spirit level and centered by U-fork so that point ‘a’ is just over station A. The north line is marked on the right hand top corner of the sheet by trough compass.
b) With the alidade touching ‘a’, the ranging rod at B is bisected and a ray is drawn. The distance AB is measured and plotted to any suitable scale. So the point ‘b’ represents station B.
c) The table is shifted and set up over B. It is leveled and centered so that ‘b’ just over B.
Now the alidade is placed along the line ‘ba’, and the ranging rod at A is bisected by turning the table clockwise or anticlockwise. When the centering, leveling and bisection of the ranging rod at A are perfect, then the orientation is said to be perfect.