MCQs on Plane Table Surveying
Q14. Which of the following is used for determining the location of the station occupied by the plane table?
Difficulty: Easy
Correct Answer: D. Two-point problemSolution:The two-point problem is a resection method that locates the unknown instrument station by sighting two known plotted points from an auxiliary station and then from the target station itself. Intersection and radiation locate external features, not the instrument station. Resection (including the two-point problem) is specifically for fixing the plane table’s own position.
Q15. The ‘fix’ of a plane table from three known points is good if:
Difficulty: Medium
Correct Answer: A. Middle station is nearestSolution:For a strong three-point fix, the instrument station should be closest to the middle of the three known reference points. This geometry ensures that the three resection rays intersect at well-separated angles, giving a precise fix and reducing the risk of the instrument falling on or near the danger circle where the three-point problem becomes indeterminate.
Q16. Radiation, intersection and resection are:
Difficulty: Easy
Correct Answer: D. Plane table surveying techniquesSolution:Radiation, intersection, resection, and traversing are the four primary field methods of plane table surveying. Radiation plots nearby accessible detail; intersection locates inaccessible points; resection fixes the instrument station; traversing links successive stations. No other surveying type uses all of these graphical methods simultaneously.
Q17. The type of surveying which requires the least office work is:
Difficulty: Easy
Correct Answer: B. Plane table surveyingSolution:In plane table surveying, observations and map plotting are done simultaneously in the field. The map is essentially complete when field work ends. All other methods require post-field calculations and office plotting. Hence, plane table surveying requires the minimum office work of all conventional survey methods.
Q18. When compared with chain surveying, plane table is:
Difficulty: Easy
Correct Answer: A. Less accurateSolution:Plane table surveying is a graphical method subject to paper distortion, manual ray drawing, and visual sighting limitations. Chain surveying uses direct physical measurements on the ground, making it more accurate. Plane table is best for small-scale topographic mapping where graphical precision is sufficient, not for high-accuracy engineering work.
Q19. Detailed plotting in plane table surveying is generally done by:
Difficulty: Easy
Correct Answer: B. RadiationSolution:Radiation is the standard method for plotting ground detail. From a central instrument station, rays are drawn to each detail point and the measured distances are scaled along the rays. It is fast and efficient for populating detail around a single setup. Traversing establishes control stations; resection locates the instrument station itself.
Q20. The intersection method in plane table surveying is most suitable for:
Difficulty: Easy
Correct Answer: C. Hilly areasSolution:Intersection requires no direct distance to the target point — only sighting rays from two known stations. This makes it ideal for hilly terrain where peaks, cliffs, and ridges are visible but physically inaccessible. Radiation requires measurable distances; traversing requires access to all stations. Intersection overcomes the inaccessibility constraint inherent to rugged terrain.
Q21. Which of the following instruments is used for measurement and sighting of objects in a plane table survey?
Difficulty: Easy
Correct Answer: A. AlidadeSolution:The alidade is the primary observation instrument of plane table surveying. Its fiducial edge is placed on the plotted station; the sighting vanes or telescope are aligned to the target; a directional ray is drawn along the edge. Clinometer measures slope angles; cross staff and prism square set out right angles in chain surveying — none of these are used for sighting in plane table work.
Q22. If the plane table is not horizontal in a direction at right angles to the alidade, the line of sight is parallel to the fiducial edge only for:
Difficulty: Medium
Correct Answer: A. Horizontal sightsSolution:When the table tilts perpendicular to the alidade, a horizontal sight (level target) is unaffected because the sight line stays in the tilted plane which still passes through the fiducial edge correctly for a zero elevation angle. For inclined sights (up or down), the tilt introduces a lateral deviation between the line of sight and the fiducial edge, causing a plotting error.
Q23. In which of the following types of surveying is the instrument alidade used?
Difficulty: Easy
Correct Answer: D. Plane table surveyingSolution:The alidade is exclusively associated with plane table surveying. Chain surveying uses tapes, ranging rods, and cross staffs (no alidade). Tacheometric surveying uses a theodolite or total station. Aerial surveying uses cameras and photogrammetric equipment. Whenever “alidade” appears in an exam option, the answer is always plane table surveying.
Q24. The instrument used for accurate centering in plane table survey is:
Difficulty: Easy
Correct Answer: C. Plumbing forkSolution:The U-shaped plumbing fork places its upper arm on the station mark of the drawing sheet and suspends a plumb bob from the lower arm. When the plumb bob is directly above the ground peg, the sheet mark is vertically centred over it. (Spirit level = levelling; Alidade = sighting/ray drawing; Trough compass = orientation.)
Q25. Plotting of inaccessible points on a plane table is done by:
Difficulty: Easy
Correct Answer: B. IntersectionSolution:Intersection draws sighting rays from two known plotted stations toward the same inaccessible target. Their crossing point on the sheet fixes the target position without any distance measurement to it. Radiation requires a measurable distance; traversing requires occupying all stations; resection locates the instrument, not an external target.
Q26. The two-point problem and three-point problem are methods of:
Difficulty: Medium
Correct Answer: C. Orientation and resectionSolution:At an unknown station the table is neither oriented nor has a plotted position. The two-point and three-point problems solve both simultaneously: orientation (rotating the table so rays are parallel to ground lines) and resection (fixing the station’s plotted position on the sheet). Neither can be done without the other at an unknown station — hence the answer is both together.