CN126 Surveying Practice
School of Environment & Technology
Semester 1 Examinations 2010-2011
CN126
SURVEYING PRACTICE
Instructions to candidates
Time allowed: TWO hours
Answer ALL questions
Formula sheet provided
Booking sheets provided
Wednesday 26 January 2011, 15:30hours
Page 1 of 8
CN126 Surveying Practice
Question 1
Levelling between two TBM’s has been carried out and the readings are shown in the
table below:
BS
0.476
IS
FS
1.013
1.851
0.774
1.597
1.318
0.992
0.859
1.640
1.228
1.634
1.806
REMARKS
TBM 47.819
A
B (CP)
C
D
E
F (CP)
G
H
TBM 46.794
(a) Calculate corrected reduced levels for all the points in the levelling table. Use
the rise and fall booking sheet provided including any checks that are required.
(20 marks)
(b) Calculate the allowable misclosure for this levelling
(4 marks)
(c) What are the advantages and disadvantages of the HPC method of level
booking?
(3 marks)
(d) Why is it necessary to try and keep sight lengths as equal as possible when
levelling?
(2 marks)
(e) Explain what is meant by the term change point?
(2 marks)
(f) Why is it necessary to close back onto a known point when carrying out any
levelling?
(2 marks)
(g) How do you eliminate parallax from an optical level telescope?
(2 marks)
TOTAL OF 35 MARKS FOR Q1
Page 2 of 8
CN126 Surveying Practice
Question 2
The measured angles and horizontal lengths of a traverse are shown in the traverse
abstract below.
B
79.243 m
93°9’14”
C
137.854 m
137°51’26”
48.009 m
82°51’37”
D
46°6’23”
161.570 m
A
All angles shown are observed values, all distances are horizontal.
Coordinates of A are mE, mN
The bearing of line AB is 30°00’00”
(a) Calculate the unknown coordinates of points B, C and D using the traverse
calculation sheet provided
(30 marks)
(b) Calculate the Fractional Linear Misclosure (FLM) for this traverse AND
explain what the FLM represents
(5 marks)
(c) Explain what a control survey is AND describe the different stages that are
involved
(5 marks)
TOTAL OF 40 MARKS FOR Q2
Page 3 of 8
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
15°37’10”
104°12’18”
217°41’55”
289°04’31”
FR
FR
FR
FR
E
D
C
B
109°04’43”
37°41’47”
284°12’07”
195°36’55”
(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)
(b) Explain why it is necessary to centre a total station and describe the procedure
for doing this.
(5 marks)
(c) 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?
(3 marks)
(d) What is a laser or optical plummet used for when setting up a total station?
(2 marks)
TOTAL OF 25 MARKS FOR Q3
Page 4 of 8
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 5 of 8
CN126 Surveying Practice
CN126 Traverse calculation sheet QUESTION 2
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 6 of 8
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 7 of 8
CN126 Surveying Practice
CN126 Level booking sheet
QUESTION 1
Student number:.........................................
BS
IS
FS
RISE FALL
RL
Corr
CorrRL
REMARKS
Page 8 of 8