Practical Surveying Engineering Fly Levelling

Bench Marks
Bench Marks is a point of known elevation . there are three Type of Bench Marks
1-Temporary Bench Mark .
2-Permenent Bench Mark.
3-Orbitrary Bench Mark
Report No. 5
• Report Name :
• Fly and Differential leveling using (Rise&fall)
and (HI) methods
• Object :
• To find elevation [reduce level (R.L)] for differential point along ground in side the campus of Erbil Technical college.
-Close loop survey.
Fly and Differential leveling.
Checks for Errors
. Allowable error (Misclosure); Is the difference •
between the known benchmark and computed benchmark
misclosure =Known point- measured point =0
= DH •known – DH measure
The allowable error is based on an equation:
Allowable misclosure=E =C
Where: C=constant C=12 for Mountain area C=30 for
Ground levelling
R= is total distance by Km
Correction= E/n n=Number of T.P stations
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. Practical Surveying Engineering
Fly Levelling
Prepared by:
Asst. Prof. SalarK. Hussein
Ass. Lecturer Mr. Kamal Y.Abdullah
Ass. LecturerMs. DilveenH. Omar
Erbil Polytechnic University
Technical Engineering College
Civil Engineering Department

2. Bench Marks
Bench Marks is a point of known elevation . there
are three Type of Bench Marks
1-Temporary Bench Mark .
2-Permenent Bench Mark.
3-Orbitrary Bench Mark

3. •Report No. 5
•Report Name :
•Fly and Differential leveling using (Rise&fall)
and (HI) methods
•Object :
•To find elevation [reduce level (R.L)] for
differential point along ground in side the
campus of Erbil Technical college.

4. Apparatus
1 –Level . (1) No.
2-Tripod . ( 1) No.
3-Staff . ( 1) No.
4-Tape. ( 1) No.
5-Pins. ( 3) Nos.

5. 5
BM=10
0
ST1
ST2 ST3
ST4
ST5
TP1
TP2
TP3
TP4
TBM=?
Close loop survey

6. Fly and Differential leveling
(Rise&fall)(HI)methods
435.321ST
Calculations:

7. Table: Height of Instrument (HI)

8. Checks for Errors
•. Allowable error (Misclosure); Is the difference
between the known benchmark and computed
benchmark
•
misclosure=Known point-measured point =0
•= DH
known–DH
measure
The allowable error is based on an equation:
Allowable misclosure=E =C
Where: C=constant C=12 for Mountain area C=30 for
Ground levelling
R= is total distance by Km
Correction= E/n n=Number of T.P stations