ABSTRACT
Circular data arise in many scientific fields, as the observations are directions. A set of such observations on directions is referred to as directional data. In particular, directional data of two dimensions is called circular/angular data. Since angular data have many novel and distinctive characteristics, it becomes necessary to redefine linear statistical measures specially suited to circular or angular data. In this chapter, various applications of angular data along with some of the data sets are described, in addition to presenting descriptive statistics for circular or angular data. For the purpose of modelling, circular distribution is introduced and characteristic function for the same is defined for the purpose of evaluating population characteristics in addition to mentioning the existing well-known circular models. Further various methods of constructing angular models are listed as a preamble to demonstrate some of those procedures of constructing new angular models in the subsequent chapters.
