Table 1.
Path Metrics & Ensuing Methods
| Metrics | Description | Suggested References |
|---|---|---|
| Step size (length) | The displacement between two consecutive coordinate fixes | Calenge et al. 2009, Turchin 1998 |
| Heading (or absolute angle) | The direction of heading relative to some standard (e.g., initial direction, compass North) | Calenge et al. 2009, Turchin 1998 |
| Turning angle | The change in heading from one step to the next | Calenge et al. 2009, Turchin 1998 |
| Displacement | The straight-line distance from the beginning to the end point of a path | Calenge et al. 2009, Turchin 1998 |
| Net squared displacement (NSD) | The square of the straight-line distance between the start of the trajectory and the current location | Calenge et al. 2009, Turchin 1998 |
| Persistence velocity | The speed of movement in the direction of heading | Gurarie et al. 2009 |
| First passage time | The time taken to exit a circle of prescribed radius r from a relocation point at the center of this circle | Fauchald and Tveraa 2003, McKenzie et al. 2009 |
| Straightness index | The ratio of to the path length (sum of the step sizes) of the trajectory segment of interest | Benhamou 2004 |
| Tortuosity | The level of convolution in a movement path relative to a straight line | Benhamou 2004 |
| Residence time | The amount of time spent within a selected area | Barraquand and Benhamou 2008 |
| Return time (inter-visit gap) | The amount of time it takes an individual to return to a particular area after its last departure | Lyons et al. 2013 |
| Revisitation (or return) rate | The rate at which an individual returns to a particular area, where distinct visits are based on a minimum return time tr | Lyons et al. 2013, Van Moorter et al. 2016 |
| Mean duration | The average amount of time spent per visit over a number of visits to a selected area | Lyons et al. 2013 |
| Time to return | The duration of time between consecutive visits to a selected area | Bar-David et al. 2009 |
| Overall dynamic body acceleration (ODBA) | The sum of the absolute values of three orthogonal locally time-averaged accelerations | Gleiss et al. 2011, Qasem et al. 2012 |
| Behavioral state | Association of one of several discrete modes of behavior with each point on the trajectory | Getz and Saltz 2008 |
| Methods (in the context of movement ecology) | ||
| Cluster analyses | Methods for grouping trajectory points (or segments) that represent the same behavioral state (or syndrome) | Van Moorter et al. 2010 (or Abrahms et al. 2017) |
| Change-point analyses | Methods for detecting points on a trajectory where switches in behavioral states occur | Gurarie et al. 2009 |
| State-space analyses (hidden Markov models) | Methods for detecting underlying behavioral states and estimating state transition probabilities | Patterson et al. 2009 |
| Accelerometry visualization | Using tri-axial accelerometer data (e.g., OBDA) to evaluate behavioral states | Shepard et al. 2008 |
| Wavelet analysis | Method for detecting periodically varying movement and behavior patterns across all temporal scales | Polansky et al. 2010 |
| Recursion analyses | Methods for detecting movement trajectory recursions (returns to prior locations) | Berger-Tal and Bar-David 2015 |