From Glossary of Meteorology


(Also called single-grid heading.) A method utilizing grid navigation to simplify flight problems attendant to pressure-pattern flight.

A map projection is used in which the great circle course approximates a straight line, and a rectangular grid overlay is superimposed on the map projection and oriented along the central meridian of the projection. Then the great circle course makes equal angles with all north–south lines on the grid. When the net drift-correction angle is applied to correct for wind effect, the entire course may be flown on a single heading with respect to the rectangular grid overlay.
Compare single drift correction.