Statistical Models for Complex Directional Data Ghent University
Directional data are data that represent directions, e.g. the direction of wind or the direction in
which an animal moves. These data are represented as points on the unit circle or unit sphere, since
they have no "length". This renders their statistical treatment very delicate, as for instance the
simple average of two points on the sphere will result in a point lying inside the sphere and hence
not on the sphere. The ...