DETERMINATION OF TOWER HEIGHT USING OPTICAL METHOD.

Provided that the terrain is fairly leveled, and the base is accessible optical distance method can be use to determined the height of Radio tower, Communication mast and other features.
EQUIPMENT NEEDED
1. Theodolite which can be use as tacheometer
2. Levelling staff

            Use the diagram above for illustration below
METHODOLOGY
1. Set up your equipment[Theodolite] on a station.
2. Direct the Staff man with levelling staff to the base of the tower.
3. Focus on the levelling staff.
4. Tilt the telescope until it vertical axis is perpendicular to Trunnion axis(Horizontal axis), i.e (Vertical angle =00d00'00")
5. Observe and take record of staff reading[i.e Upper(U), Middle(M), Lower(L)]
6. Then, observe the top of radio tower, record the Vertical angle(Q).

COMPUTATION
VD=M    !VD=Vertical Distance

HD=100*S2.  !HD=Horizontal Distance
=100*(U - L)
Using Pythagoras theorem
TanQ=H/HD
H=HD*TanQ
A=H +VD
A=(HD*TanQ) + (VD)