Two completely elaborated examples are available to demonstrate the procedure of obtaining
a position from two measured altitudes.
In the first example, the Altitude of the Sun and the Moon are measured within a short time
interval obtaining an instantaneous fix, whereas in the second example,
the Altitude of the Sun is measured twice with several hours between the two sights.
In the latter case, the first obtained Line-of-Position must be "advanced" over the
distance and course sailed during the interval between the two sights to obtain the
position at the time of the last measurement. This means, the course and distance between
the two measurements must be recorded.