Calculates the sinuosity of a trajectory as defined by Benhamou (2004), equation 8. This is a corrected version of the sinuosity index defined in Bovet & Benhamou (1988), which is suitable for a wider range of turning angle distributions, and does not require a constant step length.
TrajSinuosity2(trj, compass.direction = NULL)A Trajectory object.
if not NULL, turning angles are calculated
for a directed walk, assuming the specified compass direction (in radians).
Otherwise, a random walk is assumed.
This function implements the formula $$S = 2[p(((1 + c)/(1 - c)) + b^2)]^{-0.5}$$ where \(p\) is the mean step length, \(c\) is the mean cosine of turning angles, and \(b\) is the coefficient of variation of the step length.
Benhamou, S. (2004). How to reliably estimate the tortuosity of an animal's path. Journal of Theoretical Biology, 229(2), 209-220. doi:10.1016/j.jtbi.2004.03.016
TrajSinuosity for the uncorrected sinuosity index.