The convergence of meridians of longitude toward the South Pole causes problems for direct geometrical comparison of structural geological and geophysical datasets in Antarctica. Rotation of data to a common reference direction can be performed using a modular arithmetic function, in order to carry out geometrical analysis of faults, dike arrays, and tectonic or ice lineaments for tectonic interpretations. Performed as a spreadsheet calculation, the function Sc = MOD [(Sm + dL), 360] is demonstrated for structural datasets from latitude >80°S in the southern Transantarctic Mountains, Ellsworth, and Pensacola Mountains. Sc is converted strike; Sm, measured strike; dL, angle in degrees longitude between reference site and study site; and 360 (the divisor), the number of degrees for the circumference of a sphere. The paper proposes a protocol for geometrical and kinematic comparison of structural and geophysical data from high South latitude in Antarctica.