What is the purpose of the "compass rose" on a chart?

The compass rose on a chart serves a vital purpose in aviation navigation as it provides both magnetic and true headings. This is crucial for pilots because understanding how to interpret these headings allows for accurate navigation. The compass rose typically displays a circle inscribed with directional markings, enabling pilots to compare their aircraft's heading to the true north and magnetic north. This information is essential for flight planning and in-flight navigation, as it helps pilots make informed decisions based on the variation between magnetic and true headings, which can affect navigation accuracy.

The other options, while relevant in the context of aviation charts, do not pertain to the specific role of the compass rose. For example, identifying potential hazards or marking navigational aid locations would generally be found in other parts of the chart's layout or legend.