Also known as cyclic data, or circular data, such data are associated, for example, with direction of travel, time of day, and day of the year. The data must not be treated linearly; it must instead be recognized that a bearing of 359° is close to a bearing of 1°, or that 23.59 is approximately 00.01 (in the 24-hour clock). As such, the data are treated as being distributed on a circle (or sphere).