Introduction to Surveying LEVELLING PROCEDURES Review of levelling • In this lecture we will cover :  Equipment and procedures  Purposes of levelling  Some definitions  Reading a staff  Temporary adjustment of level  Booking and reduction  Methods of booking  Applications Leveling:- Leveling defined as an operation for the measurement of the difference in the elevation between points or for the determination of the elevation of certain points above some given plane or surface known as the datum surface , generally is taken as the mean sea level (M S L) Leveling Is a type of surveying which is carried out for finding difference in heights in engineering projects. Leveling is required for various purposes such as for calculation of the depth of cutting and fillings, for setting out grades for sewerage and pipe lines, etc. Types of Leveling and Application I. Direct Methods : II. Indirect Leveling 1. Simple Levelling . 2. Compound Levelling or Differential Levelling. 3.Flying Levelling. 4-Contours map 5. Longitudinal or profile Levelling. 6. Cross-section Levelling. 7.Reciprocal Levelling. 8-Precise Levelling. Level instrument Types of Level Instruments & Parts of level instrument 1. Dumpy Level 2. Tilting Level 3. Automatic Level 4. Electronic Level 5. Hand Level 6-Digital level -Temporary adjustment of level. -The procedure is repeated.. till the bubble remains in the center in both the positions. -Leveling staves *Types of Staff (Rod). Reading Staff. What is Leveling? Prepared by: Asst. Prof. Salar K.Hussein Mr. Kamal Y.Abdullah Asst.Lecturer. Dilveen H. Omar Erbil Polytechnic University Technical Engineering College Civil Engineering Department

1. Erbil Polytechnic University
Technical Engineering College
Civil Engineering Department
Introduction to Surveying 2020-2021.
LEVELLING PROCEDURES
Prepared by:
Asst. Prof. Salar K.Hussein
Mr. Kamal Y.Abdullah
Asst.Lecturer. Dilveen H. Omar
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2. Review of levelling
• In this lecture we will cover :
 Equipment and procedures
 Purposes of levelling
 Some definitions
 Reading a staff
 Temporary adjustment of level
 Booking and reduction
 Methods of booking
 Applications
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3. Leveling:-
Leveling defined as an operation for the measurement of the
difference in the elevation between points or for the determination
of the elevation of certain points above some given plane or
surface known as the datum surface , generally is taken as the
mean sea level (M S L)
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4. Leveling
Is a type of surveying which is carried out for finding difference in
heights in engineering projects. Leveling is required for various
purposes such as for
calculation of the depth of cutting and fillings, for setting out
grades for sewerage and pipe lines, etc.
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5. Types of Leveling and Application
I. Direct Methods :
1. Simple levelling:
2. Compound levelling:
3. Differential or Flying Leveling and Check : Set the equipment at many
different places.
4.Contours map by level instrument.
5. Longitudinal , Profile
6.cross-leveling .
7. Reciprocal Leveling.
8. Precise Leveling.
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6. II. Indirect Leveling
If there is a barrier prevent the use of instrument.
1. Trigonometrically, 2. Barometric,
Equipment:
1. Level instrument .
2. Tripod
3. Staff
4. Staff bubble
5. 50 m tape measure (sometimes)
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7. 1. Simple Levelling : -
This method Set the instrument at one point and read another
point. enables us to determine the difference in level between two points
by placing the instrument approximately mid way between the two
stations ,
while taking the readings, the bubble remain in the center as usual.
A
R.L=100.00
2.200
B.S
2.700
F.S
Staff reading at A = 2.200
Height of collimation = 100 + 2.200 = 102.200
Staff reading at B = 2.700
R.L of B = 102.20 - 2.700 = 99.500 m
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8. 2. Compound Levelling or Differential Levelling :-
Set the instrument at one point and read the other points. involves
the same process as simple Levelling but in addition, a number of
setting of the instrument are required to find out the difference in
Levelling between two points in (the case where a single setting
cannot serve the purpose), this maybe either due to a large
distance.
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9. 3.Flying Levelling:
The reduced levels(RL) of some important points is found,
by a few selected setting of the instrument.
to get a rough idea of the nature of the ground.
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10. 4-Contours map
A map showing the natural and cultural features as well
as showing the nature of the surface of the land (topography of the
land) of the up and downs and its representation in (3D)three
dimensions.
A contour is a line drawn on a plan joining all points of the same
height above or below a datum.
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11. 5. Longitudinal or profile Levelling:-
Longitudinal levelling is an operation of doing a levelling job to determine
the profile of a ground surface along a given line; this is generally the
center line of a purposed alignment, such as railway, highway, canal,
and pipeline.
The proposed alignment may be a single or series of straight lines
connected by curves,
the points are selected at a uniform interval.
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12. 6. Cross-section Levelling:-
In longitudinal section the center line is taken, but when a winder belt is
required for some engineering project, e.g. highway, railway etc.
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13. 7.Reciprocal Levelling :-
When two station are situated far apart and it is not possible to set up the
instrument in between these stations because of a river or deep valley and also
not possible to equalize the back sight and fore sight the process of
(reciprocal Levelling )is adopted. The method avoid of applying any correction due
curvature refraction and imperfect line of collimation.
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14. 8-Precise Levelling:-
Leveling done with at most careful and pre caution and with the most refined
instrument to establish the control point is called precise Levelling .
A systematic procedure of taking field observation and recording is adopted to
minimized and eliminate all sources of error..
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15. Level instrument
Types of Level Instruments & Parts of level instrument
1. Dumpy Level
2. Tilting Level
3. Automatic Level
4. Electronic Level
5. Hand Level
6-Digital level
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16. Temporary adjustment of level
1- A suitable position is selected for setting the level from the position it
should be possible to take the greatest number of observation without any
difficulty the ground should be rightly level and firm.
2- The instrument in fixed on the tripod.
3- The tripod are adjusted according to one’s high.
4- The three foot screw are brought to the center

17. .5- The telescope is placed parallel to any two foot screws and by turning
both the two screws either in or out as required. The bubble of the
telescope is brought to center
6- The telescope is brought over to the third foot screw by rotating it
through 90˚. The bubble is brought to the center by turning the third foot
screw only.
The procedure is repeated.. till the bubble remains in the center in both the
positions.
7- Finally the levelly of the instrument is verified by turning the telescope
in any direction when the bubbles remain in the central position for any
direction of the telescope the (staff reading are taken)

18. Leveling staves
• The rod Is a graduated straight rod made of wooded rod and Aluminium.
height of staff (3m, 5m ), used for measuring the vertical distance between the
pointes on the ground and the line collimation and rectangular in cross-section.
The graduations are units of staff reading (meters , decimeters ,cm and
millimeters). The bottom of the staff represents zero reading. All divisions are
written in black against white ground,
•
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19. Types of staff, (rod)
1) Solid Staff.
2) Folding Staff.
3-Telescope Staff.
4-Invar Leveling Staff.
5-Aluminium levelling staff.
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20. Reading an “E -face” staff
0.300
0.33
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21. What is levelling?
• A measurement process where by the Elevation or difference in
height between two or more points can be determined.
• Levelling is the method, which is used widely, to obtain the
elevations (RL) of ground points to a reference datum.
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