Calculates x-y coordinates for a set of radial axes (one per variable being plotted in radar plot)
CalculateAxisPath(var.names, min, max)
list of variables to be plotted on radar plot
MININUM value required for the plotted axes (same value will be applied to all axes)
MAXIMUM value required for the plotted axes (same value will be applied to all axes)
a dataframe of the calculated axis paths