How to Plot a Line of Position From the Distance to a Landmark

If you have a rangefinder, radar or some other means of measuring the distance to an object on your chart, you can use this range to plot a line of position.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• The distance measured with any means at your disposal
• Pencil
• Paper
• Clock
• Chart
• Plotting compass

How to Plot the Distance From an Object

1. Write down the time and measured range from the charted object.

2. Open the plotting compass to the range measured from the object by placing the sharp, pointed end along a north-south edge of the chart, and opening up the pencil side of the compass to the measured distance using the relation that "1 nautical mile is equal to 1 minute of arc" along the north-south scale.

3. Put the sharp point into the chart at the charted object.

4. Draw an arc of a circle on the chart approximately where you are at on the chart. This is your Line of Position.