In the grid azimuth conversion, t denotes which angle?

• A. Geodetic Azimuth
• B. Grid Azimuth
• C. True Azimuth
• D. Back Azimuth

Answer: (B)

Grid azimuth conversion uses grid north as the reference direction, so the angle denoted by t is the grid azimuth—the angle from grid north to the line you’re measuring. This is different from true or geodetic azimuth, which are measured from true north or geodetic north, and from back azimuth, which is the opposite direction of a given azimuth.

A helpful point: grid north is rotated from true north by the grid convergence angle, and you use that relationship to convert between true azimuth and grid azimuth (for example, GA = TA minus the convergence). For instance, if the true azimuth is 45 degrees and the grid convergence is 5 degrees clockwise, the grid azimuth would be 40 degrees.