Book CoverCircular Statistics in R provides the most comprehensive guide to the analysis of circular data in over a decade. Circular data arise in many scientific contexts, both from angular observations, and from daily or seasonal activity patterns.

Examples of the former include the: observed compass directions of departure from a release point of radio-collared migratory birds; bond angles measured in different molecules; wind directions at different times of the year at a wind farm; directions of stress-fractures in concrete bridge supports; longitudes of earthquake epicenters. 

Examples of the latter include the:  times of the day at which animals are caught in a camera trap or 911 calls are received in New York; variation throughout the year in measles incidence, global energy requirements, TV viewing figures or injuries to athletes. The natural way to represent such data graphically is as points located around the circumference of a circle, hence their name.

Importantly, circular variables are periodic in nature, and the origin, or zero point, such as the beginning of a new year, is defined arbitrarily rather than necessarily emerging naturally from the system.

This book will be of value both to those new to circular data analysis as well as those more familiar with the field. For beginners, the authors start by considering the fundamental graphical and numerical summaries used to represent circular data before introducing distributions that might be used to model them. When discussing model fitting, the authors advocate reduced reliance on the classical von Mises distribution; showcasing distributions that are capable of modelling features such as asymmetry and varying levels of kurtosis that are often exhibited by circular data.

The use of likelihood-based and computer-intensive approaches to inference and modelling are stressed throughout the book. The R programming language is used to implement the methodology. Also provided are over 150 new functions for techniques not already covered within R.

This concise but authoritative guide is accessible to the diverse range of scientists who have circular data to analyse and want to do so as easily and as effectively as possible.