Several textbooks describe a method of plotting that differs from the one proposed in this book. In contrast with the one recommended earlier, the alternative method involves rotating the tracing paper above a stationary net. The alternative procedure is best explained with reference to an actual example.

Plotting a plane 060/30SE as a great circle and a pole

1. 1 Mark the north mark and the strike direction 060 on the tracing paper (Fig. A7d).

2. 2 Keeping the net still, rotate the tracing paper until the strike mark aligns with the axis point of all small circles on the net (Fig. A7e).

3. 3 Trace the appropriate great circle, i.e. the one found by counting in 30° from the ‘south’ (Fig. A7e). This is great circle for the plane 060/30SE.

4. 4 With the tracing held in the position, count out an angle of 90° from this great circle. This gives the pole of the plane 060/30SE.

5. 5 The completed stereogram is shown in Figure A7f.

Plotting a line 30–050

1. 1 Rotate the tracing until the north point rests adjacent to the 050° bearing on the underlying net.

2. 2 Now measure 30° along the 0–180 diameter of the net from the periphery at 0 towards the centre and insert the point representing the line 30–050.

3. 3 Restore the tracing to its correct alignment.