Chain & Tape Work – Best Tool for Measuring Short Offsets from a Baseline In basic chain surveying, very short perpendicular offsets to locate details (walls, hedges, building corners) are typically measured using which tool under ordinary site accuracy requirements?

Introduction / Context:
Short offsets are common in detail surveying. Choosing the right measuring tool affects speed, flexibility, and accuracy. This question checks your practical knowledge of which tape or chain is commonly used for short, frequent offsets in routine topographic work.

Given Data / Assumptions:

• Offsets are short (a few metres).
• Required accuracy is that of ordinary chain surveying.
• Environment may involve frequent contact with ground and obstacles.

Concept / Approach:

Metallic tapes (linen or synthetic fabric reinforced with metallic wires) are light, flexible, and easy to handle repeatedly at short lengths. They are fast for small offsets and sufficiently accurate for ordinary detail work. Steel tapes are more accurate but heavier and typically reserved for longer measurements where precision justifies handling effort. Invar tapes are for high-precision baselines and are unnecessary for short offsets. Ordinary chains are cumbersome for very small perpendiculars and do not drape well around obstacles.

Step-by-Step Solution:

Verification / Alternative check:

Field handbooks recommend metallic tapes (or light fibreglass tapes) for rapid offsetting, reserving steel/invar tapes for higher precision tasks.

Why Other Options Are Wrong:

Ordinary chains are unwieldy for short offsets; invar is overkill; steel tapes are accurate but slower for repeated short measures; fibreglass is acceptable but not the standard answer in classical chain surveying texts.

Common Pitfalls:

Using a heavy steel tape when speed is the priority; attempting short offsets with a bulky chain leading to alignment errors.

Final Answer:

A metallic tape