Height of Instrument Method | Surveying and Levelling



Height of the Instrument Method

The following readings were observed with a levelling instrument, the instrument was shifted after 5th and 11th reading.

0.585, 1.010, 1.735, 3.295, 3.775(5th)

0.350, 1.300, 1.795, 2.575, 3.375

3.895 (11th), 1.735, 0.635, 1.605

Determine the RLs of various points if the reduced level (RL) of a point on which the first reading was taken is 136.440 gives the height of collimation method and applies the check.

Station BS IS FS HI RL Remarks
123

4

5

0.585 

 

0.350

1.0101.735

3.295

 

 

3.775

137.025 

 

133.600

136.440136.015135.290

133.730

133.250

RL of I point 

 

CPI

678

9

10

 

 

1.735

1.3001.7952.575

3.375

 

 

3.895

 

 

131.440

132.300

131.805

131.025

130.225

129.705

CP II
1112 0.635 1.605 130.805

129.835

Sum of BS=2.670 Sum of FS =9.275

HL = RL + BS

= 136.440 + 0.585

= 137.025

RL = HL – IS

Check

(Summation of BS)-(Summation of FS) = Last RL – First RL

2.670 – 9.275 = 129.835 – 136.440

-6.605 = -6.605



6 thoughts on “Height of Instrument Method | Surveying and Levelling”

Leave a Comment