What is the LARS rule when converting a magnetic azimuth to a grid azimuth?

The LARS rule is a mnemonic device used to help individuals correctly convert a magnetic azimuth to a grid azimuth in navigation and land navigation tasks. The acronym LARS stands for "Left Add, Right Subtract," which highlights the actions needed depending on the direction of the conversion.

When converting a magnetic azimuth to a grid azimuth, if you’re navigating from a magnetic source and need to account for how the magnetic north differs from grid north, you must adjust your azimuth based on whether you are moving left or right on a map.

Specifically, if your point of reference (magnetic north) is to the left of your location relative to grid north, you would add the necessary degrees to your azimuth, hence "Left Add." Conversely, if your magnetic north is to the right, you would subtract the degrees from your azimuth, which follows the "Right Subtract" directive. This method ensures that you accurately account for the differences between magnetic and grid orientations.

The clarity of LARS helps military personnel avoid confusion during critical navigation tasks, ensuring they can orient themselves properly and accurately represent their movement on a map. Understanding and applying LARS is vital for tactical success in the field.