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Ishik University / Sulaimani
Civil Engineering Department
SURVEYING 1
CE 215
CHAPTER -3-
METHODS OF LEVELING
Ishik University / Sulaimani Assistant Lecturer /Asmaa Abdulmajeed
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Methods of Levelling:
1. Height of Collimation Method (HI)
2. Rise and Fall Method
Ishik University / Sulaimani Assistant Lecturer /Asmaa Abdulmajeed
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1. Height of Collimation Method (HI)
It consist of finding the elevation of the plane of collimation ( H.I.) for
every set up of the instrument, and then obtaining the reduced level of
point with reference to the respective plane of collimation.
1. Elevation of plane of collimation for the first set of the level
determined by adding back side to R.L. of B.M.
2. The R.L. of intermediate point and first change point are then
obtained by starching the staff reading taken on respective point
(IS & FS) from the elevation of the plane collimation. [H.I.]
3. When the instrument is shifted to the second position a new plane
collimation is set up. The elevation of this plane is obtained by
adding B.S. taken on the C.P. From the second position of the
level to the R.L. C.P. The R.L. of successive point and second C.P.
are found by subtract these staff reading from the elevation of
second plane of collimation.
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Arithmetical check
Sum of B.S. – Sum of F.S. = last R.L. – First R.L.
This method is simple and easy.
Reduction of levels is easy.
Visualization is not necessary regarding the nature of the ground.
There is no check for intermediate sight readings
This method is generally used where more number of readings
can be taken with less number of change points for constructional
work and profile leveling.
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2. Rise and Fall Method
It consists of determining the difference of elevation between
consecutive points by comparing each point after the first that
immediately preceding it. The difference between there staff
reading indicates a rise, fall according to the staff reading at the
point. The R.L is then found adding the rise to, or subtracting the
fall from the reduced level of preceding point.
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This method is complicated and is not easy to carry out.
Reduction of levels takes more time.
Visualization is necessary regarding the nature of the ground.
Complete check is there for all readings.
This method is preferable for check levelling where number of
change points are more.
Arithmetic check
Sum of B.S. – Sum of F. S. = Sum of rise – Sum of fall
= Last R. L. – First R.L.
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Example -1-
Calculate R.L. by HI method, Use arithmetic checks to
support your results.
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Solution;
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Solution;
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Solution;
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Solution;
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Solution;
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Solution;
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Solution;
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Example -2-
The following staff readings were observed successively with
a level, the instrument is moved after third reading. Calculate
R.L. if the first reading was taken at a B.M of 50m. Use arithmetic
checks to support your results.
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Solution; HI Method
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Rise and Fall Method
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Reduce the given booking data below using (a) the Rise & Fall
and (b) HPC methods. Use arithmetic checks to support your
results.
Example -3-
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Solution; (a) Rise & Fall method:
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Solution;
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(b) HPC method: Solution;
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Solution;
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Example -4-
(a) The data from a survey, are shown below. Use either the Rise and Fall
method or the Height of Plane of Collimation (HPC) method to reduce
the data.
(b) Use arithmetic checks to support your answer.
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Example -4-
(a) The data from a survey, are shown below. Use either the Rise and Fall
method or the Height of Plane of Collimation (HPC) method to reduce
the data.
(b) Use arithmetic checks to support your answer.
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The following staff readings were observed successively with a level
the instrument is moved by third sixth and eighth readings. : 2.228
:1.606 :0.988 :2.090 :2.864 :1.262 0.602 :1.982 :1.044 :2.684 m
enter the reading in record book and calculate R.L. if the first
reading was taken at a B.M of 432.383m
Use;
1. H.I. method
2. Rise and Fall method
Use arithmetic checks to support your results.
Assignment- 1-
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Assignment- 2-