TrajectoryMetrics: steps, headings, turning angles (wrapped to
\((-\pi, \pi]\)), straightness (Batschelet 1981) and Benhamou (2004)
sinuosity. MeanSquaredDisplacement: time-averaged MSD by lag.
FirstPassageTime: Fauchald and Tveraa (2003) FPT with linear
interpolation of the circle crossings. SimulateWalk: correlated
(wrapped Cauchy), biased and Levy walks from Philox uniforms (streams 0
and 1). OdMatrix: origin-destination counts. Identical to the
Python arm morie.fn.movetraj.
Usage
TrajectoryMetrics(track)
MeanSquaredDisplacement(track, max_lag = NULL)
FirstPassageTime(track, times, radius)
SimulateWalk(
n_steps,
kind = "correlated",
step = 1,
rho = 0.8,
mu = 2,
target = c(0, 0),
bias = 0.5,
start = c(0, 0),
seed = 1L
)
OdMatrix(origins, destinations, zones = NULL, weights = NULL)Arguments
- track
Two-column matrix of positions.
- max_lag
Maximum lag.
- times
Fix times.
- radius
Circle radius.
- n_steps
Number of steps.
- kind
"correlated","biased"or"levy".- step
Step length (Levy minimum step).
- rho
Wrapped Cauchy concentration.
- mu
Levy tail exponent.
- target
Target of the biased walk.
- bias
Weight of the target heading.
- start
Starting position.
- seed
Philox seed.
- origins, destinations
Zone labels of each trip.
- zones
Zone order.
- weights
Trip weights.
References
Benhamou, S. (2004). How to reliably estimate the tortuosity of an animal's path: straightness, sinuosity, or fractal dimension? Journal of Theoretical Biology 229, 209-220.
Fauchald, P. and Tveraa, T. (2003). Using first-passage time in the analysis of area-restricted search and habitat selection. Ecology 84, 282-288.
Codling, E. A., Plank, M. J. and Benhamou, S. (2008). Random walk models in biology. Journal of the Royal Society Interface 5, 813-834.