Definition
Because each position line carries an uncertainty band rather than being a perfect line, the intersection defines an area whose shape depends on the angle of cut and the accuracy of each observation. A bearing accurate to plus or minus 3 degrees produces a band about 0.16 nautical miles wide at 3 nautical miles range, since one degree subtends roughly one mile at 60 miles. Navigators use the ellipse to judge safe clearance rather than treating the plotted dot as exact.
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