Ranging in chain surveying: Ranging is primarily the operation of what activity in the field?

Introduction / Context:
To measure a straight distance accurately with a chain or tape, the line between the two terminal stations must be clearly defined and kept straight. Ranging is the process used to align and mark intermediate points so that measurement proceeds along the intended straight line without lateral deviation.

Given Data / Assumptions:

• Two terminal points are intervisible or can be connected in stages.
• Ranging rods or flags are available for alignment.
• Survey crew includes a leader and a follower for communication and sighting.

Concept / Approach:
In direct ranging, the observer aligns an intermediate rod so that it lies visually on the straight line joining the two terminals; in indirect ranging (hilly/obstructed terrain), reciprocal or step-by-step methods are used. Once intermediate points are fixed, chaining proceeds accurately along the straight line through these points.

Step-by-Step Solution:

Verification / Alternative check:
Re-check alignment from the opposite terminal; small deviations appear as apparent lateral offsets of the intermediate rod, prompting fine corrections.

Why Other Options Are Wrong:

• Reconnaissance is preliminary planning, not line alignment.
• Judging distance by eye is estimation, not the act of aligning.
• Determination of slope uses clinometers/levels and is independent of ranging.

Common Pitfalls:
Parallax due to not sighting with one eye; using bent or poorly painted rods; failing to check alignment from both ends.

Final Answer:
Establishing intermediate points in straight line between terminal stations