Symbolic Directions
Directions shift all chart points by the same arc, proportional to the years lived. Unlike transits, nothing moves across the actual sky here: the chart itself moves, and the speed is set by a symbolic measure.
Solar arc uses the movement of the progressed Sun, about 1 degree per year, which varies for each chart. Naibod arc uses a fixed rate of 0°59'08" per year, the average daily motion of the Sun, and is therefore the same for all.