The document outlines a practical approach to surveying engineering, specifically focusing on fly levelling methods for determining elevation points at Erbil Polytechnic University. It categorizes benchmarks into three types: temporary, permanent, and arbitrary, and details the equipment and methodology used in differential leveling, including a closed loop survey. Additionally, it discusses error checks and allowable misclosure calculations in surveying.

1. Practical Surveying Engineering
Fly Levelling
Prepared by:
Asst. Prof. Salar K. Hussein
Ass. Lecturer Mr. Kamal Y.Abdullah
Ass. Lecturer Ms. Dilveen H. 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
435.321 ST
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