There may be times in the field when you do not know where you are on the map or you may need to communicate your position location to the Operations Section or Situation Unit. One method to estimate your own position is called triangulation. It involves sighting on two known landmarks (you know where they are on the map) and where those lines of position intersect is where your position is located. The information below outlines one method to determine your own position using triangulation and is illustrated in the image below.
Steps to determine your own position using triangulation.
- Adjust compass for declination
- Locate two or more objects (e.g., topographic features, structures), that can be identified on the map. It is best if the objects are approximately 90 degrees apart to reduce potential errors.
- Take a bearing to each of the objects.
- Convert to back bearings
- On the map, draw the lines of the back bearing from the objects; these are called lines of position. The point where these lines intersect is your position.
**Information adapted from the National Interagency
Incident Management System Basic Land Navigation
Manual, PMS 475 dated June 2007.