What do principal baselines describe?

What do principal baselines describe?

• A. Run north & south
• B. Horizontal lines that run East & West (32 baseline)
• C. Circular lines
• D. Vertical lines

Answer: (B)

Principal baselines describe horizontal reference lines that run East and West. In a grid or map coordinate system, this baseline provides the primary horizontal orientation from which measurements are taken. Distances north or south are measured perpendicular to this baseline, creating parallel lines that form the northing component, while the East‑West direction aligns with the baseline itself. A line running North and South would be a vertical reference, not the principal baseline, and circular lines don’t serve as the straight reference needed for establishing a gridded framework.

Principal baselines describe horizontal reference lines that run East and West. In a grid or map coordinate system, this baseline provides the primary horizontal orientation from which measurements are taken. Distances north or south are measured perpendicular to this baseline, creating parallel lines that form the northing component, while the East‑West direction aligns with the baseline itself. A line running North and South would be a vertical reference, not the principal baseline, and circular lines don’t serve as the straight reference needed for establishing a gridded framework.