On radar displays we use range rings from the radar head,usually 5 or 10 miles.
Track miles.It depends where they are in the radar circuit.
Downwind: I would range and bearing from the point I intend turning base.(10+6+ whatever the distance to that point)
Closer in: Measure from the 10 mile final point.
Most radar now have the RBL function,but being old school I can do just as good a job with the mark one pen and thumb.
