Surveying and Levelling : DETERMINATION OF THE AREA OF CLOSED TRAVERSE : Practical 5

 DETERMINATION OF THE AREA OF CLOSED TRAVERSE

Aim:- 

To find the area of the given boundary by perpendicular offset method.

Instruments Required: 

Chain (30m), Ranging rods, arrows, Pegs, cross staff.

Formulae:- 

Area of the triangle A= ½ bh sq.units.

Area of the trapezium A= ½ h (a+b) sq.units. 

Procedure:-

1. The survey stations are fixed. 

2. To range a line AB, the ranging rods are fixed at the end of the line.

3. The surveyors stand just behind the ranging rod A. The assistant holds a ranging rod at 

point C, approximately on the line AB.

4. Locate the perpendicular offset by using cross staff.

5. Move the cross staff towards left / right.

6. Now base line (AB) is visible and perpendicular line also visible.

7. Perpendicular line measurements are taken.

8. The operation is repeated until the end station of the line is reached.

9. To check the accuracy of the measurement, the line is measured in the reverse direction.      

10. Split the area, by triangle and trapezoidal.

11. Calculate the area by using triangle and trapezoidal formula. 

Result:- 

The area of the field = …………………………………