Plane table surveying: evaluate the following statements and select the correct combination of true statements for small-scale field work and plotting by resection/traverse.

Introduction / Context:Plane table surveying combines observation and plotting in the field, making it effective for small-scale mapping and rapid topographic detail. Understanding which operational statements are valid helps avoid common procedural errors and improves the reliability of the plotted plan.

Given Data / Assumptions:

• Statements: (1) less accurate than chain surveying, (2) accurate centering is not essential for small scale, (3) compass rule may adjust a plane-table traverse, (4) resectors (resection lines) are drawn from the station to plot object positions.
• Small-scale survey context is assumed.

Concept / Approach:For small-scale work, minor centering errors translate into negligible plotting errors; hence (2) is acceptable. A plane-table traverse can be adjusted by approximate rules such as the compass (Bowditch) rule; thus (3) is valid. Plotting by resection (drawing lines of sight to determine an object's position) is a standard plane-table technique; therefore (4) is correct. Statement (1) is not generally true: plane-table plotting can be more reliable than chain-and-compass note plotting for detail work, though it is less precise than theodolite methods.

Step-by-Step Solution:Assess (2): small scale reduces sensitivity to centering → true.Assess (3): compass rule used for traverse adjustment → true.Assess (4): resection lines from station are standard → true.Assess (1): comparison to chain surveying is not strictly 'less accurate' → treat as false in this context.

Verification / Alternative check:Surveying texts describe plane-table resection methods (two-point/three-point) and allow approximate traverse adjustment by compass rule for small works.

Why Other Options Are Wrong:

• Any option including statement (1) incorrectly assumes plane-table is always less accurate than chain surveying.

Common Pitfalls:Overgeneralizing accuracy comparisons; forgetting that the required accuracy depends on scale and purpose.

Final Answer:2, 3 and 4 are correct