Question

With neat sketch, explain the included angle method of plotting compass traverse. 

Answer 1

1. Calculate all included angles of the traverse from observed bearings of the lines.

e.g. <A, <B, <C, <D, <E

 2. Check sum of included angles as equal to (2n – 4) x 90, where n is number of sides of closed traverse.

 3. Pick a convenient point e.g. ’A’. The point is so chosen that the whole traverse can be plotted properly with a suitable selected scale. Mark the north direction through A, set out AB in direction of its bearing and measure the length AB to the scale to mark point B.

 4. Set out the included angle B to obtain the direction of BC. Set out length BC to the scale to mark point C.

5. Repeat the procedure at other stations to set out all lines of traverse. The last point when set should coincide with starting station (in case of closed traverse). If there is closing error, it needs to be corrected.