what is a compass rose

A compass rose, sometimes called a wind rose, rose of the winds, or compass star, is a figure on a compass, map, nautical chart, or monument used to display the orientation of the cardinal directions and their intermediate points. It is a symbol on a map that shows the cardinal directions, which are the main compass points: north, south, east, and west. Some more elaborate compass roses show additional directions, such as the ordinal, or intercardinal, directions, which are the points halfway between each cardinal direction, including northwest, northeast, southwest, and southeast. The contemporary compass rose appears as two rings, one smaller and set inside the other. The outside ring denotes true cardinal directions while the smaller inside ring denotes magnetic cardinal directions. True north refers to the geographical location of the north pole while magnetic north refers to the direction towards which the north pole of a magnetic object (as found in a compass) will point. The term "rose" comes from the figures compass points resembling the petals of a flower. The compass rose is used to show how the map lines up with real directions, and it is present on charts and maps since the 1300s when the portolan charts first made their appearance.