Triangulation is also used to estimate the location of an unknown position. For example, two field observers spot smoke. The field observers know their own position locations but they don’t know the position of the smoke. They can determine the location of the smoke by taking a bearing and plotting it on the map. The intersection of the two lines is the location of the smoke. The information below outlines one method for estimating unknown positions and is illustrated in the image below.
Steps to estimate an unknown position.
- Adjust compass for declination
- Take a bearing from two or more known locations to the unknown position.
- Plot bearings on the map and draw connecting lines. The point where the lines intersect is the approximate location of the previously unknown position.
**Information adapted from the National Interagency
Incident Management System Basic Land Navigation
Manual, PMS 475 dated June 2007.