1
1. TITLE
Profile Levelling
2. OBJECTIVES
After the field operations, the students should determine the elevations of
turning points, intermediate points and benchmarks. Also, the students
should plot the profile along the centreline of a certain track of land.
3. MATERIALS
3.1.
3.2.
3.3.
Automatic Level/Dumpy Level with Tripod
Stadia Rods
Marker (Chalk)
4. PROCEDURES
4.1.
Establish markings at entry full stations along the line and on the
benchmarks assigned on the ground.
4.2.
Set up and level the instrument in a suitable location on one side of a
line.
4.3.
Take and record a backsight on a rod held on a known benchmark to
determine the height of instrument.
4.4.
Take and record intermediate foresight from as many points on the
line up to within practical limits of sightings.
4.5.
When the rod has been advance to point beyond which readings to
ground points cannot be observe, establish a turning point, and take a
foresight on it determine its elevation.
4.6. Transfer and Set up the instrument in another farther position and take
a backsight on the turning point just establish. Then continue taking rod
readings on ground points as before until the end of the line is reached.
4.7.
The height of the instrument can be computed by adding the
backsight reading to the known elevation and the elevation of the ground
point are calculated by subtracting the corresponding foresight to the
height of the instrument.
4.8.
The error of closure is the difference between the sum of all
backsights and foresights and also equal to the difference in elevation
between the first and final benchmarks.
4.9.
The elevation of then intermediate station can be calculated by
subtracting the intermediate foresight from the height of the instrument.
4.10. Tabulate, Observe, and Computed values accordingly.
4.11.
Take photographs for documentation.
5. ILLUSTRATION
6. DATA TABULATIO
STA
BS
BM1
IP1
1.432
IFS
1.418
FS
HI
ELEV
1.432
0
0.014
REMAR
KS
IP2
IP3
TP1
TP1
IP1
IP2
IP3
TP2
TP2
IP1
IP2
IP3
TP3
TP3
IP1
IP2
IP3
TP4
TP4
IP1
IP2
IP3
TP5
TP5
IP1
IP2
IP3
TP5
BM2
1.408
1.397
1.39
0
1.452
0.024
0.035
0.332
1.452
1.455
1.459
1.460
1.453
0
1.435
0.003
0.007
0.008
0.001
1.435
1.428
1.419
1.415
1.40
0
1.455
0.007
0.016
0.002
0.035
1.455
1.410
1.437
1.435
1.432
0
1.405
0.015
0.016
0.020
0.023
1.405
1.413
1.415
1.415
1.432
0
1.453
1.445
1.443
1.448
1.453
0.008
0.010
0.010
0.023
1.453
0.080
0.010
0.005
0
1.439
7. PRESENTATION AND ANALYSIS
Profile leveling is a method of surveying that has been carried out
along the central line of a track of land on which a linear engineering work is
to be constructed/ laid. The operations involved in determining the elevation
of ground surface at small spatial interval along a line is called profile
leveling[1].
With given procedures the member set points to represent
bm1.Another member marked another point Tp1, near the bm1 to get the
backsight, foresight and intermediate foresight to determine the distance of
each. The same procedure is done for bm2, determine the backsight then
intermediate foresight, to determine if the center of each makings is
balanced.
Therefore he group concluded that with approximated values of
elevation and height shows that the measurements are not far from each
other, proving that the recorded data have a minimal error that maybe
caused by some mistakes or careless of measuring, holding the stadia rods
and etc.
HG= ELEV+BS
ELEV= HI-FS
1.432+0=1.432
1.418-1.432=0.01
1.408-1.432=0.024
1.397-1.432=0.032
1.452+0=1.452
1.455-1.452=0.003
1.459-1.452=0.007
1.460-1.452=0.003
1.453+0=1.453
1.445-1.453=0.081
1.443-1.453=0.010
1.488-1.453=0.005
1.453-1.453=0
1.435+0=1.435
1.428-1.435=0.007
1.419-1.435=0.016
1.415-1.435=0.020
1.453-1.452=0.001
1.400-1.435=0.035
1.455+0=1.455
1.440-1.455=0.015
1.439-1.455=0.016
1.435-1.455=0.021
1.432-1.455=0.027
8. REMARKS AND RECOMMENDATIONS
Profile leveling is a method of surveying that has been carried out
along the central line of a track of land on which a linear engineering work
is to be constructed/ laid.
This activity is done to determine if the ground level from one point to
another is equal, to have an accurate result, the participants must balance
the bubble of the specimen. Also, the stadia rod should be held by
participants must be standing still. The calculations of the data must be
correct.
8. DOCUMENTATION
