Linear Measurement Methods – Which Gives Greater Accuracy Under Normal Conditions? Considering standard field practice and instrument capabilities, which method generally provides the highest accuracy in measuring linear distances?

Introduction:
Linear measurement accuracy depends on the method and equipment. While tacheometry is fast and useful for topographic detail, its distance precision is limited by angular reading and staff intercept errors. Direct measurement with a properly standardized steel tape (and applied corrections) yields superior accuracy for baselines and control lines.

Given Data / Assumptions:

• Ordinary field conditions (no EDM considered).
• Careful taping with temperature, pull, sag, and alignment corrections.
• Chaining refers to link-chain use, typically less precise than steel tapes.

Concept / Approach:

Direct steel-tape measurement minimizes intermediate computations and leverages instrument calibration. Systematic effects can be modeled and corrected, enabling sub-centimeter accuracy over tens of meters. Tachymetric distances, even with good instruments, rarely match high-grade taping due to compounding angular and staff reading uncertainties. Link chains further suffer from wear, kinks, and poor standardization compared to steel tapes.

Step-by-Step Solution:

Verification / Alternative check:

Specifications for baseline measurements prescribe steel tapes (or EDM) with detailed corrections, reflecting recognized superior accuracy over tachymetric methods.

Why Other Options Are Wrong:

(a) and (b) are generally less precise; (d) is false because methods are not equally accurate; (e) is the least accurate and used only for reconnaissance.

Common Pitfalls:

Overestimating tachymetric accuracy; neglecting tape standardization and correction application which are essential to realize the method’s potential.

Final Answer:

Direct steel-tape measurement (taping) with corrections