Given a set of locations defining a trajectory, this function approximates their instantaneous instantaneous angular speeds computed as the difference between successive headings divided by the time between these successive headings.
Arguments
- x
A vector of x (or longitude) coordinates corresponding to a single trajectory.
- y
A vector of y (or latitude) coordinates corresponding to a single trajectory.
- t
A vector of timestamps corresponding to a single trajectory.
- geo
A logical value indicating whether the locations are defined by geographic coordinates (pairs of longitude/latitude values). Default: FALSE.
Value
A vector of the same length as x, y and t corresponding to the approximated instantaneous angular speeds along the trajectory.
Author
Simon Garnier, garnier@njit.edu
Examples
x <- rnorm(25)
y <- rnorm(25, sd = 3)
t <- as.POSIXct(1:25, origin = Sys.time())
ang_speed(x, y, t)
#> [1] NA NA 1.0453698 2.4359684 2.8847242 0.0577974
#> [7] -2.8722883 -0.4654643 1.2958490 -3.0284013 -2.7203884 1.9972050
#> [13] 2.8402990 -0.2308750 -3.0501015 -0.1410135 -3.0359444 -0.3844565
#> [19] -2.8368930 -0.4656028 -2.9640589 1.1543182 2.5608694 3.0630419
#> [25] -1.9425550