How to Extract Latitude and Longitude from a Known Position
You have now learned how to plot a position. Now lets extract the
latitude and longitude from a known position. Lets find the position of
the fix labeled 1520 in figure 1-15 . This is easily accomplished by
following these steps:
1. Place the point of the compass directly beneath the position to be
extracted on the closest parallel. Now open the compass and swing an
arc that passes through the position.
2. Move your compass over to the latitude and read the latitude from
the scale. Now repeat the procedure using the closest meridian as a
You have now learned how to plot and extract positions on the chart.
Hopefully, the previous discussion on the terrestrial coordinate system is
now clear. If not, now is a good time to review the material once again.
Lets continue to take a closer look at our chart, where it comes from,
how it is kept up to date.
Figure 1-15. Thats it, the point where the two arcs intersect is the position.