Running angle

In mathematics, the running angle is the angle of consecutive vectors ${\displaystyle (Xt,Yt)}$ with respect to the base line, i.e.

${\displaystyle \phi (t)=\arctan \left({\frac {\Delta Yt}{\Delta Xt}}\right).}$

Usually, it is more informative to compute it using a four-quadrant version of the arctan function in a mathematical software library.