Error detection in controlled traverses (theodolite): pick the correct statements about locating gross errors in bearing or taping. Read each technique and decide which are valid ways to isolate the blundered station or leg.

Difficulty: Medium

To locate a gross bearing error in a controlled theodolite traverse, plot the traverse from each end. The station whose plotted coordinates coincide by both routes is the one where the error lies.
To locate a gross bearing error in a controlled traverse, plot the traverse and identify the station through which the perpendicular to the sector of the closing line passes; that station is where the error was made.
To locate a gross error due to taping in a controlled traverse, plot the traverse to a convenient scale; the bearing of the closing error will be approximately the same as that of the leg containing the gross length error.
All the above.
None of the above

Correct Answer: All the above.

Explanation:

Introduction / Context:
In a controlled theodolite traverse, gross blunders (wrong bearing, transposed angle, wrong length) can seriously distort closure. Practical graphical diagnostics help pinpoint the fault before recomputing or recollecting data. This question asks which plotting-based techniques are valid for isolating the blundered station or leg.

Given Data / Assumptions:

A closed or controlled traverse with known start/end control.
One dominant gross error (bearing or length) assumed.
Angles and lengths otherwise consistent; plotting to a reasonable scale.

Concept / Approach:

Graphical error-hunting relies on the geometry of misclosure. Re-plotting from opposite ends, examining the direction of misclosure, and relating the closing-error vector to individual legs provide clues about where the blunder sits. These time-tested methods are found in traverse adjustment practice and field troubleshooting guides.

Step-by-Step Solution:

Method 1 (Plot from each end): If coordinates of a particular station agree when plotted forward and backward, the inconsistency leading to misclosure must lie at that station. This reveals a bearing blunder local to that point.Method 2 (Perpendicular through sector of closing line): Drawing a perpendicular to the sector of the closing line that intersects the traverse suggests the likely faulty station (bearing mistake), where angular sense changed incorrectly.Method 3 (Closing-error bearing vs. leg bearing): If length (taping) of one leg is grossly wrong, the misclosure vector tends to align roughly with that leg’s bearing; plotting at a convenient scale makes this evident.

Verification / Alternative check:

After identifying the suspect station/leg, recompute with corrected data or perform an independent check (repeat sight/measure). If adjusted, the traverse should close within permitted tolerances using Bowditch or transit rules.

Why Other Options Are Wrong:

Each of A, B, and C is a recognized diagnostic; therefore selecting anything other than “All the above” ignores valid techniques.

Common Pitfalls:

Assuming multiple simultaneous gross errors (these methods are most effective when a single dominant blunder exists); plotting at too small a scale to see directionality; confusing systematic drift with one-off blunders.

Final Answer:

All the above.

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Error detection in controlled traverses (theodolite): pick the correct statements about locating gross errors in bearing or taping. Read each technique and decide which are valid ways to isolate the blundered station or leg.

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