Table 7.

Direction of movement expressed as labelled turning angles.

Turning Angle (Degrees)	Direction	Direction ID
45 $\le {\tau }_i$ or ${\tau }_i\ge 315$	Forward	1
${\tau }_i>$ 45 and ${\tau }_i<135$	Left	2
${\tau }_i\ge$ 225 and ${\tau }_i<315$	Right	3
${\tau }_i\ge$ 135 and ${\tau }_i<225$	Backward	4