A Polar Chart is a common circular chart representing a closed curve connecting points in the polar coordinate system. Each data point is defined by the distance from the radial coordinate and the angle from the angular coordinate. Polar Chart is also called radar chart, spider chart, web chart, star chart or star plot. This type of chart is often used when one wants to show a comparison data similar to a pie chart, but also show a scale of values for context.
A Nightingale Rose Chart (Coxcomb Chart or Polar Area Diagram) is a combination of the Radar Chart and Stacked Column Chart. It is helpful when working with cyclic data (months, seasons, years, etc.) and with statistical data. Meteorologists use it to illustrate a wind rose.