Section 4: Soil and Water Conservation Engineering
Surveying and Levelling
Subtopic: Plane table surveying
Question Statement:
Which of the following field methods are standard procedures employed in plane table surveying for locating details or instrument stations?
Options:
(A) Radiation method (suitable when all surrounding stations are clearly visible and accessible from one setup)
(B) Intersection method (ideal for locating distant, inaccessible, or mountainous points by intersecting sight rays)
(C) Traversing method (used to run survey lines between consecutive plane table stations)
(D) Resection method (used to establish the location of the plane table station with respect to previously plotted control points)
Answer Key:
A, B, C, D
Step-by-Step Solution & Explanation
All four methods are the canonical operational modes in plane table surveying:
- Radiation: Rays drawn from single station to target points, distances measured directly.
- Intersection: Target points located by intersection of rays from two known stations without measuring distance to target.
- Traversing: Similar to theodolite traversing, orienting at each station.
- Resection: Orientation and station determination via Three-point or Two-point problems (e.g., Lehmann's method).