Baseline measurement corrections: which of the following standard corrections apply to a measured base of length L taken with a tape in geodetic work?

Introduction / Context:
High-precision baseline measurement requires applying systematic corrections so that the reported length represents a horizontal, sea-level-reduced value under standard conditions.

Given Data / Assumptions:

• Measured length L with a suspended or supported tape.
• Known tape weight per unit length w and applied pull P.
• End height difference h; mean elevation H above MSL.

Concept / Approach:
Key corrections include sag (catenary effect), slope (to convert to horizontal), and mean sea level (to project to reference surface). Typical forms are:C_s = (w^2 * L^3) / (24 * P^2)C_θ ≈ - h^2 / (2 * L) for small slopesC_msl = - L * (H / R)

Step-by-Step Solution:
Apply sag correction to remove lengthening due to tape sag.Apply slope correction to reduce to horizontal length.Reduce to MSL using site elevation and Earth radius.

Verification / Alternative check:
Geodetic surveying manuals present these standard corrections; refined forms exist for large slopes and temperature calibration but the above are canonical.

Why Other Options Are Wrong:

• Each listed correction is required; omitting any leads to bias.

Common Pitfalls:

• Confusing sign conventions; remember sag and MSL corrections are subtractive.

Final Answer:
all the above