There are two methods available for finding the height of an object.
- Tape and ranging rods method.
- instrumental method.
1.Tape and ranging rods method.:- This method is used where
the ground is level and the object is accessible.
the ground is level and the object is accessible.
In the above picture PR be the object whose height to be determined. Where P be the peak and R be the base of the object. Two ranging rod W and U are fixed on the level ground at some distance from R. Two mark V and T marked on the ranging rod W and U. Looking through V and T mark the point Q on the PR. Then VW=TU=QR=h1. Sight the P from V so that S and P are in the same line. Measure the distance WU, WR and ST.
There are two triangles PQV AND STV formed.
PQ/QV=ST/TV
PQ= ST/TV*QV (Here TV=WU and WR=QV)
Thus PR= PQ+h1
2. Instrumental method:-
PROCESS:- Set the theodolite at O, levelled the instrument used plate level and altitude level. Measured the distance QR with the chain or tape. The angle of elevation A and angle of depression B also measure. Let the distance OR = D. Then use the tan formula.
h2 = D* TAN A
h3=D*TAN B
Total height of the PR : h2+h3
RL OF P= BM+h1+h2
RL OF Q= BM+h1-h2
