Open Traversing with the help of Theodolite

By deflection angle method

• Bearing of the first line AB is measured with the help of prismatic compass or by any other method.
• Setup the theodolite and point B and with horizontal circle reading bisect point A.
• Transit the telescope and rotate it in the direction of next station point C and note the angle, this will be θ1 R and is called deflection angle at B.
• Repeat this procedure for the remaining points of traverse measuring the deflection angle and writing with them letter "L" or "R".
• For calculation of bearing we have to simply add the deflection angles right ® to bearing of previous line to find out the bearing of next line and subtract the deflection angle left (L) from the bearing of previous line to find out the bearing of next line.

Example

let θ1 = 35°, θ2 = 55°, θ3 = 45°,

By direct Bearing method

• Bearing of first line AB is determined by any method.
• Setup the instrument at point B.
• Set the horizontal circle reading at the Back Bearing of of AB and bisect the back station A.
• Rotate the instrument in clockwise direction and bisect the next point C. The circle reading will give directly bearing of line BC.
• Repeat the procedure for remaining lines.