CN126 Surveying Practice
School of Environment & Technology
Semester 1 Examinations 2009-2010
CN126
SURVEYING PRACTICE
Instructions to candidates
Time allowed: TWO hours
Answer ALL questions
Formula sheet provided
Booking sheets provided
Page 1 of 9
CN126 Surveying Practice
Question 1
The measured angles and horizontal lengths of a traverse are shown in the traverse
abstract below.
C
45°25’40”
244.823 m
76.417 m
152°04’21”
D
B
115°04’28”
148.540 m
266.455 m
47°26’11”
A
All angles shown are observed values, all distances are horizontal.
Coordinates of A are 160.500 mE, 185.000 mN
The bearing of line AB is 30°00’00”
(a) Calculate the coordinates of the unknown stations B, C and D
(30 marks)
(b) Calculate the fractional linear misclosure (FLM)
(5 marks)
Page 2 of 9
CN126 Surveying Practice
Question 2
Levelling between two TBM’s has been carried out and the readings are shown in the
table below.
BS
0.841
IS
FS
1.231
1.492
1.004
2.329
1.648
1.823
0.329
1.564
0.847
1.209
0.891
REMARKS
TBM 38.912
A
B
C
D (CP)
E
F (CP)
G
H
TBM 38.299
(a) Calculate corrected reduced levels for all the points in the levelling table. Use
the rise and fall booking sheet provided.
(20 marks)
Page 3 of 9
CN126 Surveying Practice
Question 3
The horizontal angle readings shown below are taken using a total station that has
been correctly set up and levelled above point A.
Face
Point sighted
Horizontal circle reading
FL
FL
FL
FL
B
C
D
E
00° 12’ 18”
96° 17’ 28”
211° 04’ 56”
328° 54’ 32”
FR
FR
FR
FR
E
D
C
B
148° 54’ 47”
31° 05’ 08”
276° 17’ 35”
180° 12’ 36”
(a) Book the readings in a suitable format on the booking sheet provided and
calculate values for the horizontal angles BC, CD and DE
(15 marks)
Page 4 of 9
CN126 Surveying Practice
Question 4
(a) Some levelling was carried out where six instrument positions were used.
What is the allowable error for this levelling?
(b) Explain why it is necessary to centre a total station and describe the procedure
for doing this.
(c) Why is it necessary to try and keep sight lengths as equal as possible when
levelling?
(d) What are the advantages and disadvantages of the HPC method of level
booking?
(e) In a traverse what does the fractional linear misclosure represent and how is it
calculated?
(f) How can you check the measured angles in a polygon traverse?
(g) Why is it advisable to take face left and face right values and to take at least
two rounds when measuring angles with a total station or theodolite?
(h) What is a laser or optical plummet used for when setting up a total station?
(i) How do you eliminate parallax from an optical level telescope?
(j) Why is it necessary to close back onto a known point when carrying out any
levelling?
(3 marks each)
(Total of 30 Marks for question 4)
Page 5 of 9
CN126 Surveying Practice
FORMULA SHEET
Levelling misclosure e = ±5√N
 angles  2n4 90
E  D sin 
N  D cos 
e  e E2  e N2
E  
D
eE
L
N  
D
eN
L
Page 6 of 9
CN126 Surveying Practice
CN126 Traverse calculation sheet QUESTION 1
Line
Line
Back bearing
Adjusted angle
Forward bearing
Coordinate differences
Whole circle bearing
θ
Distance
d
Station
Station
Student Number:..................................................
Coordinates
Calculated
ΔE
ΔN
Adjustments
δE
δN
Page 7 of 9
Adjusted
ΔE
ΔN
E
N
CN126 Surveying Practice
CN126 Angle booking sheet
QUESTION 3
Student Number:.........................................
STATION
HORIZONTAL CIRCLE
POINT
DIAGRAM
FACE LEFT
FACE RIGHT
REDUCED
DIRECTION
MEAN
FINAL ANGLES
REMARKS
SURVEY TITLE
DATE
THEODOLITE HEIGHT
THEODOLITE NUMBER
OBSERVER
BOOKER
Page 8 of 9
CN126 Surveying Practice
CN126 Level booking sheet
QUESTION 2
Student number:.........................................
BS
IS
FS
RISE FALL
RL
Corr
CorrRL
REMARKS
Page 9 of 9