FES Study Guide: 2026/2027 Syllabus
Module 1: Fundamentals & Measurements
1. What is the primary purpose of surveying?
ANSWER ✓ To determine the relative position of points on or near the Earth's surface.
2. Define "Geoid" in the context of surveying.
ANSWER ✓ The equipotential surface of the Earth's gravity field that coincides with
mean sea level.
3. What is the difference between "accuracy" and "precision"?
ANSWER ✓ Accuracy is the degree of conformity with a standard (truth), while precision
is the degree of refinement or consistency of a measurement.
4. A distance is measured as 150.56m with a 30m tape that is 0.02m too long.
What is the correction per tape length?
ANSWER ✓ +0.02m (correction is additive).
5. What is the formula for the correction due to temperature in taping?
ANSWER ✓ Ct=αL(T−Ts)Ct=αL(T−Ts), where αα is the coefficient of thermal
expansion, LL is the length, TT is the field temperature, and TsTs is the standardization
temperature.
6. What is the principle of "reciprocal levelling"?
ANSWER ✓ It is used to eliminate errors due to collimation, earth curvature, and
refraction by taking readings from two instrument positions equidistant from the two
points.
7. List four sources of error in taping.
ANSWER ✓ (1) Incorrect tape length, (2) temperature variation, (3) sag, (4) poor
alignment.
8. How is "sag correction" applied in taping?
ANSWER ✓ It is always negative and is calculated using Cs=−W2L324P2Cs=−24P2W2L3
, where WW is weight per unit length, LL is the unsupported length, and PP is the pull
applied.
, 9. What is the difference between a "plumb bob" and a "range pole"?
ANSWER ✓ A plumb bob establishes a vertical line/point, while a range pole is used to
mark points and establish a straight line.
10. Define "scale of a map".
ANSWER ✓ The ratio of a distance on the map to the corresponding distance on the
ground (e.g., 1:10,000).
Module 2: Leveling & Vertical Control
11. What is "benchmark" (BM)?
ANSWER ✓ A relatively permanent point of known elevation used as a reference for
leveling.
12. Define "backsight" (BS).
ANSWER ✓ The first reading taken on a point of known elevation after setting up the
instrument.
13. Define "foresight" (FS).
ANSWER ✓ The last reading taken on a point whose elevation is to be determined
before moving the instrument.
14. What is the formula for "height of instrument" (HI)?
ANSWER ✓ HI=ElevationBM+BSHI=ElevationBM+BS
15. How do you compute the elevation of a point using the HI method?
ANSWER ✓ ElevationPoint=HI−FSElevationPoint=HI−FS
16. What is the "curvature correction" in leveling?
ANSWER ✓ The correction for the Earth's curvature,
approximately 0.0785×(distance in km)20.0785×(distance in km)2 meters (negative
to the reading).
17. What is the "refraction correction" in leveling?
ANSWER ✓ The correction for atmospheric refraction,
approximately 0.011×(distance in km)20.011×(distance in km)2 meters (positive to
the reading).
Module 1: Fundamentals & Measurements
1. What is the primary purpose of surveying?
ANSWER ✓ To determine the relative position of points on or near the Earth's surface.
2. Define "Geoid" in the context of surveying.
ANSWER ✓ The equipotential surface of the Earth's gravity field that coincides with
mean sea level.
3. What is the difference between "accuracy" and "precision"?
ANSWER ✓ Accuracy is the degree of conformity with a standard (truth), while precision
is the degree of refinement or consistency of a measurement.
4. A distance is measured as 150.56m with a 30m tape that is 0.02m too long.
What is the correction per tape length?
ANSWER ✓ +0.02m (correction is additive).
5. What is the formula for the correction due to temperature in taping?
ANSWER ✓ Ct=αL(T−Ts)Ct=αL(T−Ts), where αα is the coefficient of thermal
expansion, LL is the length, TT is the field temperature, and TsTs is the standardization
temperature.
6. What is the principle of "reciprocal levelling"?
ANSWER ✓ It is used to eliminate errors due to collimation, earth curvature, and
refraction by taking readings from two instrument positions equidistant from the two
points.
7. List four sources of error in taping.
ANSWER ✓ (1) Incorrect tape length, (2) temperature variation, (3) sag, (4) poor
alignment.
8. How is "sag correction" applied in taping?
ANSWER ✓ It is always negative and is calculated using Cs=−W2L324P2Cs=−24P2W2L3
, where WW is weight per unit length, LL is the unsupported length, and PP is the pull
applied.
, 9. What is the difference between a "plumb bob" and a "range pole"?
ANSWER ✓ A plumb bob establishes a vertical line/point, while a range pole is used to
mark points and establish a straight line.
10. Define "scale of a map".
ANSWER ✓ The ratio of a distance on the map to the corresponding distance on the
ground (e.g., 1:10,000).
Module 2: Leveling & Vertical Control
11. What is "benchmark" (BM)?
ANSWER ✓ A relatively permanent point of known elevation used as a reference for
leveling.
12. Define "backsight" (BS).
ANSWER ✓ The first reading taken on a point of known elevation after setting up the
instrument.
13. Define "foresight" (FS).
ANSWER ✓ The last reading taken on a point whose elevation is to be determined
before moving the instrument.
14. What is the formula for "height of instrument" (HI)?
ANSWER ✓ HI=ElevationBM+BSHI=ElevationBM+BS
15. How do you compute the elevation of a point using the HI method?
ANSWER ✓ ElevationPoint=HI−FSElevationPoint=HI−FS
16. What is the "curvature correction" in leveling?
ANSWER ✓ The correction for the Earth's curvature,
approximately 0.0785×(distance in km)20.0785×(distance in km)2 meters (negative
to the reading).
17. What is the "refraction correction" in leveling?
ANSWER ✓ The correction for atmospheric refraction,
approximately 0.011×(distance in km)20.011×(distance in km)2 meters (positive to
the reading).
