because the bearing
applies to the segment extending from the current location.</p>
<p>To use this on multiple track ids, use a grouped data frame with tidyverse code like
<code>data %&gt;% group_by(id) %&gt;% mutate(turn = track_bearing(lon, lat))</code>.</p>
<p>Absolute bearing is relative to North (0), and proceeds clockwise positive and anti-clockwise
negative <code>N = 0, E = 90, S = +/-180, W = -90</code>.</p>
<p>The last value will be <code>NA</code> as the bearing is relative to the first point of e