The arrowhead data consists of outlines of the images of arrowheads.
The shapes of the projectile points are converted into a time series using
the angle-based method. The classification of projectile points is an
important topic in anthropology. The classes are based on shape distinctions
such as the presence and location of a notch in the arrow. The problem in the
repository is a length normalized version of that used in Ye09shapelets.
The three classes are called "Avonlea", "Clovis" and "Mix".