Start a tangential arc using the previous point with the same code to define the entry tangent.
- A control code at the entry tangent point with the action 'Arc Start (Tangential)'.
- A point preceding the entry tangent point with the same feature code.
Control Code Definition
A control code action 'Arc Start (Tangential)' is given a value 'STA'.
A control code action 'Arc End (Tangential)' is given a value 'ETA'.
Measured Points
The first point (pt 9) is assigned the code 'BCK' (Back of Kerb) and it defines the start of the entry tangent for the arc.
The second point (pt 10) is assigned the code 'BCK STA'.
The third point (pt 11) is assigned the code 'BCK ETA'.
The fourth point (pt 12) is assigned the code 'BCK' and it defines the end of the exit tangent.
- Creates a two dimensional circular arc.
- When a 'Arc Start (Tangential)' control code action is encountered, the next point in the same sequence should contain the 'Arc End (Tangential)' control code action.
- All four points required to form the tangential arc, must have the same feature code.
