1Survey I
Lecture 4
Out lines
❖ Leveling.
❖ Instruments.
❖ Types of levels.
❖ Basic Principle of Leveling
❖ Types of leveling.
2
31- Level is an instrument which is used for observing staff
reading on leveling staff kept over different points.
2- Staff. Is simply a large ruler, available in lengths of 3, 4 or 5
meters and usually made of aluminum with telescopic sections.
Reading the Staff
Color Alternates every meter each graduation is 100mm, each
“E” is 50mm
meter height & 1/10m is located in lower 50mm each Part of the E is 10mm
millimeters are interpolated staff is read to the millimeter.
Leveling Instruments.
4Staff Reading
Stadia Reduction
The middle line is the line of
Collimation, the short lines are
called stadia lines usually stadia
multiplier is 100
Collimation is an imaginary
line that passes through the level
instrument at the cross hairs.
5Basic Principle of Leveling
6Basic Principle of Leveling
B/S 2.510
F/S 1.202
Diff Between 1.308
B/S 2.301
F/S 1.517
Diff Between 0.784
7Basic Principle of Leveling
Basic Rules for Leveling
➢ Always start and finish a levelling run on a Benchmark (BM )
and close the loop.
➢ Keep fore sight and back sight distances as equal as possible.
➢ Keep lines of sight short (normally < 50m).
➢ Never read below 0.5m on a staff (refraction).
➢ Use stable, well defined change points.
➢ Beware of shadowing effects and crossing waters.
8
9Leveling Types
1- Height of Instrument (H.I) method
H.I = Elev. B.M + B.S
10Example
The following staff readings
0.915, 2.672, 3.145, 2.112, 1.215, 1.725, 2.315, 3.315, 3.623, 1.292, 1.550, 2.355
The level was shifted after second and 6th and 9th reading , the elevation of B.M
= 323.300
Calculate the elevations of the points.
11Solution .
1- H.I method
H.I = B.M Elev. + B.S
Elev. of any point = H.I – Staff Reading ( I.S or F.S)
No. Point B.S I.S F.S H.I Elev. (m) Remarks
1 A 0.915 324.215 323.300 B.M
2 B 3.145 2.672 324.688 321.543
3 C 2.112 322.576
4 D 1.215 323.473
5 E 2.315 1.725 325.278 322.963
6 F 3.315 321.963
7 G 1.292 3.623 322.947 321.655
8 H 1.550 321.397
9 I 2.355 320.592
12Solution.
Check Check the calculations:
ΣBS – ΣFS = Last Elev. - First Elev.
(7.667 - 10.375) = (320.592 - 323.300) = - 2.708
13Rise and Fall method
Difference in height (ΔH)= Last reading – Next reading =
To find the elevation of other points
Next Elev. = Last Elev. + R or Next Elev. = Last Elev. – F
To check the calculations:
ΣBS – ΣFS = Σ Rises – Σ Falls = Last Elev. - First Elev.
( + ) R
( - ) F
14Leveling.
Example
The following staff reading
0.915, 2.672, 3.145, 2.112, 1.215, 1.725, 2.315, 3.315, 3.623, 1.292, 1.550,
2.355
The level was shifted after second and 6th and 9th reading , the elevation of
B.M = 323.300
Calculate the elevations of the points. Using :
1- Rise and Fall method.
15Solution.2- Rise and Fall method
# point B.S I.S F.S Rise Fall Elev. (m) Remarks
1 A 0.915 323.300 B.M
2 B 3.145 2.672 1.757 321.543
3 C 2.112 1.033 322.576 T.P
4 D 1.215 0.897 323.473
5 E 2.315 1.725 0.510 322.963 T.P
6 F 3.315 1.000 321.963
7 G 1.292 3.623 0.308 321.655 T.P
8 H 1.550 0.258 321.397
9 I 2.355 0.805 320.592
∑ = 7.667 = 10.375 = 1.930 = 4.638
One Loop(-)
(-)
(-)
(-)
(-)
(+)
(+)(=)
(=)
(=)
(=)
(=)
(=)
(=)
16Solution.
2- Rise and Fall method Check the calculations:
ΣBS – ΣFS = Σ Rises – Σ Falls = Last Elev. - First Elev.
7.667 - 10.375 = 1.930 - 4.638 = 320.592 - 323.300 = - 2.708
17Example:
The following staff readings were taken on an ascending land, 1-
1- Find the elevations of another points.
2- Check the calculations.
The staff reading on the B.M with elev. 445.325 m was 1.5651.565, 2.315, 1.891, 1.565, 1.016, 0.730, 3.150, 2.635,1.925,1.252, 0.835, 2.831,
2.085, 1.731, 1.205, and 0.895
# Points B.S I.S F.S H.I Elev. Remarks
1 A 1.565 446.890 445.325 B.M
2 B 2.315 444.575 First #
3 C 1.891 444.999
4 D 1.565 445.325
5 E 1.016 445.874
6 F 3.150 0.730 449.310 446.160 T.P1
7 G 2.635 446.675
8 H 1.925 447.385
9 I 1.252 448.058
10 J 2.831 0.835 451.306 448.475 T.P2
11 K 2.085 449.221
12 L 1.731 449.575
13 M 1.205 450.101
14 N 0.895 450.411 Last #
18Solution.1- H.I method
19Solution.2- Rise and Fall method
# Points B.S I.S B.S Rise Fall Elev. Remarks
1 A 1.565 445.325 B.M
2 B 2.315 0.750 444.575 First #
3 C 1.891 0.424 444.999
4 D 1.565 0.326 445.325
5 E 1.016 0.549 445.874
6 F 3.150 0.730 0.286 446.160 T.P1
7 G 2.635 0.515 446.675
8 H 1.925 0.710 447.385
9 I 1.252 0.673 448.058
10 J 2.831 0.835 0.417 448.475 T.P2
11 K 2.085 0.746 449.221
12 L 1.731 0.354 449.575
13 M 1.205 0.526 450.101
14 N 0.895 0.310 450.411 Last #
∑ 7.546 2.460 5.836 0.750
References 20
Ghilani, C. D. and P. R. WOLF (2014). Elementary Surveying: An Introduction to Geomatics . New Jersey, PEARSON.
Uren, J. and B. Price (2010). Surveying for Engineers. UK, PALGRAVE MACMILLAN.
Barry F. Kavanagh – 7th – ed. SURVEYING with ConstructionApplications. PEARSON.
21End of Lecture 4