Classical triangulation — essential characteristics Which of the following statements correctly describe classical triangulation surveys?

Introduction / Context:
Before modern GNSS, triangulation provided the backbone of national geodetic frameworks. Its principles still inform the design of control networks and the adjustment of observational data. Understanding what is directly measured and what is computed is fundamental.

Given Data / Assumptions:

• A classical triangulation scheme with a measured baseline.
• High-precision theodolite angle measurements.
• Network of triangles covering the area.

Concept / Approach:
A measured baseline seeds the network with known length. Angles at network vertices are observed precisely; using the law of sines, other sides are computed and propagated throughout the network. Stations in the triangulation serve as control for subsequent detailed (plane table, EDM, total-station, or GNSS) surveys.

Step-by-Step Solution:

Verification / Alternative check:
Historic national triangulations (e.g., Great Trigonometrical Survey) followed exactly this approach, validating each listed statement.

Why Other Options Are Wrong:

• Each statement is correct; hence “All of the above.”

Common Pitfalls:
Allowing skinny triangles (poor condition); neglecting rigorous least-squares adjustment; insufficient baseline checks.

Final Answer:
All of the above