A typical oblique Mercator projection.
A type of conformal map projection in which the cylinder is tangent at a great circle other than the equator or the meridian. The line of tangency can be any great circle. The projection is used principally to depict an area near the vicinity of an oblique great circle, such as along the great-circle route between two important centers that are a relatively great distance apart. The x
-axis of the projection is a great-circle course at true scale. The scale is equal to the secant of the angular distance from the x
-axis. This makes the projection almost ideal for strip charts of great circles. The scale expansion and the area distortion in the region of the oblique pole are the same as that of the standard Mercator in the region. The rhumb lines, meridians, and parallels of latitude are curved lines. Radio bearings cannot be plotted directly onto these charts.