Report Levelling
LEVELLING (Two Peg Test)
Introduction
Two Peg test need to carry out before we start the levelling job to ensure the instrument in good condition 1.0 Aim
Peg Test is a surveying operation carried out to determine if the leveling bubble (bubble axis) and telescope line-of-sight ( line of collimation )are parallel.
2.0 Equipments 3.1 Level and Tripod ( 1 set) 3.2 Staff ( 2 sets ) 3.3 Staff bubble (2 sets ) 3.4 Tape ( 1 set )
3.0 Procedures 4.5 Each group will be required to perform a peg test to check the instrument. 4.6 All person in the group should recorded the result of the peg test in their own field book. 4.7 Two point some 60 m apart are set out and marked the ground (with wooden pegs driven into the earth, or roofing nails in tar) 4.8 The instrument are set up midway between two pegs [figure 3.1] 4.9 The staff are read on each peg (back sight and foresight), and the height difference are calculated. 4.10 The instrument are moved about L/10 = 6m beyond one of the pegs (normally fore staff position). [figure 3.2] 4.11 The staff are read on each peg again, and the height difference are calculated.
I. First, we need to measure by tape 30m from point C to point A and B. Choose flat area for this test and observe the staff A and B.
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II. After that, the auto level move to point D where is about L/10 meter. L is total length from point A to B. Jot down the Staff A and B reading.
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III. Do camparison between 2 set of readings
4.0 Observation Data and Analysis | Reading Staff B (s1) | Reading Staff B (s2) | Height difference=m | First set up | 1.325 | 1.325 | 0 |
| Reading Staff B (s1’) | Reading Staff B (s2’) | Height difference=m’ | Second set up | 1.388 | 1.390 | 0.002 |
Difference(m-m’) | 60m | | |
5.12 if m=m’ then the instrument is ok! 5.13 If NOT then the error is
e= (S1-S2) – (S1’ – S2’ ) / L mm/m =(1.325-1,325) –
Introduction
Two Peg test need to carry out before we start the levelling job to ensure the instrument in good condition 1.0 Aim
Peg Test is a surveying operation carried out to determine if the leveling bubble (bubble axis) and telescope line-of-sight ( line of collimation )are parallel.
2.0 Equipments 3.1 Level and Tripod ( 1 set) 3.2 Staff ( 2 sets ) 3.3 Staff bubble (2 sets ) 3.4 Tape ( 1 set )
3.0 Procedures 4.5 Each group will be required to perform a peg test to check the instrument. 4.6 All person in the group should recorded the result of the peg test in their own field book. 4.7 Two point some 60 m apart are set out and marked the ground (with wooden pegs driven into the earth, or roofing nails in tar) 4.8 The instrument are set up midway between two pegs [figure 3.1] 4.9 The staff are read on each peg (back sight and foresight), and the height difference are calculated. 4.10 The instrument are moved about L/10 = 6m beyond one of the pegs (normally fore staff position). [figure 3.2] 4.11 The staff are read on each peg again, and the height difference are calculated.
I. First, we need to measure by tape 30m from point C to point A and B. Choose flat area for this test and observe the staff A and B.
|
II. After that, the auto level move to point D where is about L/10 meter. L is total length from point A to B. Jot down the Staff A and B reading.
|
III. Do camparison between 2 set of readings
4.0 Observation Data and Analysis | Reading Staff B (s1) | Reading Staff B (s2) | Height difference=m | First set up | 1.325 | 1.325 | 0 |
| Reading Staff B (s1’) | Reading Staff B (s2’) | Height difference=m’ | Second set up | 1.388 | 1.390 | 0.002 |
Difference(m-m’) | 60m | | |
5.12 if m=m’ then the instrument is ok! 5.13 If NOT then the error is
e= (S1-S2) – (S1’ – S2’ ) / L mm/m =(1.325-1,325) –