LMRC AE 2017 (1-Shift)
⭕ A. Angle subtended is large
⭕ B. the station is within the great triangle
⭕ C. the station is near the great circle
⭕ D. Angle subtended is small
📚 Explanation:
A poor fix in plane table surveying occurs when the
station is located near the great circle formed by the three control points.
🔹 In this condition, the geometric intersection becomes weak.
🔹 Small angular errors produce large positional errors.
🔹 Hence, resection becomes unreliable and inaccurate.
A poor fix in plane table surveying occurs when the
station is located near the great circle formed by the three control points.
🔹 In this condition, the geometric intersection becomes weak.
🔹 Small angular errors produce large positional errors.
🔹 Hence, resection becomes unreliable and inaccurate.
👉 Therefore, the correct answer is: C. the station is near the great circle
Key Points on Poor Fix:
- Good fix: When station lies well inside the great triangle.
- Poor fix: When station lies near or on a great circle (side of the triangle).
- Reason: Small sighting errors cause large plotting errors.
