Triangulation practice: a subsidiary station chosen near a main triangulation station to bypass obstructions is commonly called a satellite/eccentric/false station. Which name is NOT used for such a subsidiary point?
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ASatellite station
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BEccentric station
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CFalse station
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DPivot station
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EOffset station
Answer
Correct Answer: Pivot station
Explanation
Introduction / Context:In triangulation surveying, obstacles (buildings, trees, relief) may prevent direct observations from a primary station. A nearby auxiliary point is then selected to carry out the required sightings while mathematically relating it back to the main station.
Given Data / Assumptions:
- Auxiliary points are near the primary station.
- Terminology in classical triangulation texts recognizes several synonyms.
- We must identify the term that is NOT standard for this purpose.
Concept / Approach:Common synonyms for a nearby auxiliary point are: satellite station, eccentric station, or false station. These reflect the idea that the observed station is not the true main point but a nearby surrogate whose relationship to the main station is known. The term “pivot station” is not a recognized synonym in this context.
Step-by-Step Solution:List known synonyms: satellite, eccentric, false station.Compare with “pivot station” which refers to rotating supports in instruments, not a subsidiary triangulation point.Therefore, “pivot station” is not used for the auxiliary point.
Verification / Alternative check:Surveying manuals consistently employ the three accepted synonyms; “pivot” relates to instrument mechanics rather than station classification.
Why Other Options Are Wrong:
- Satellite station: standard term.
- Eccentric station: standard term.
- False station: standard term in some texts.
- Offset station: also used in practical contexts.
Common Pitfalls:Assuming “pivot” refers to station naming; it does not.
Final Answer:Pivot station