Per-trajectory sinuosity for a Tracks

Computes [path_sinuosity()] (Benhamou 2004) for each trajectory in a `Tracks`, ordering each trajectory's points by its time column when one is recorded. Distance-calibrated: with a `distance_scale` set the step lengths are in real units, so the reported sinuosity is in \(1/\sqrt{\mathrm{unit}}\).

Usage

sinuosity(ts, x_col = ts@cols$x, y_col = ts@cols$y)

Arguments

ts

A `Tracks`.

x_col, y_col

Names of the coordinate columns to use. Default to the `Tracks`'s recorded x/y columns (the real recorded positions).

Value

A `data.frame` with one row per trajectory: the `Tracks`'s id column and a numeric `sinuosity` column (`>= 0`).

See also

[path_sinuosity()], [straightness_index()], [tortuosity_ratio()], [set_distance_scale()]

Examples

head(sinuosity(cpunctatus))
#>         trial_id sinuosity
#> 10_1_1    10_1_1  3.995306
#> 10_10_1  10_10_1  2.329886
#> 10_11_1  10_11_1  3.771568
#> 10_12_1  10_12_1  3.248539
#> 10_13_1  10_13_1  3.249218
#> 10_14_1  10_14_1  1.687342