Compass Rose

A graduated circular diagram showing directions and bearings from a north reference.

On a nautical chart, a compass rose commonly has an outer true-direction scale and an inner magnetic-direction scale. The magnetic information states variation for a given epoch and may show its expected annual change, so it must be updated to the date of use rather than copied blindly.

A compass card also carries a directional graduation but is part of the instrument rather than the chart. Chart roses are used to plot or read directions, while the chart’s datum, projection and local magnetic notes must still be checked.