Grid Magnetic Angle

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In this short video, we will revise Grid Magnetic Angle (GMA). This allows us to adjust our bearings when converting between grid bearings and magnetic bearings, and back again.

Summary

  • The magnetic variation is different for each map, and varies across the UK.
  • GMA stands for Grid Magnetic Angle.
  • Remember to keep track of east and west when calculating the GMA. Thankfully, at the moment we still have a variation that is west, however this is not the case elsewhere in the world.
  • The longer the distance travelled on a bearing, the more impact an incorrectly adjust bearing will have.
  • In reality, a GMA of 1 degree can probably be ignored, however anything larger and you should take it into account.

Grid to Mag – Add

Mag to Grid – Get rid

Remember this easy rhyme to add or subtract your GMA when out navigating

Cheat Sheet

As promised, here is a small cheat sheet or aide memoir you can print out and keep in your map case. There is a worked example, as well as some useful hints and tips.

Capt. Nick author is an experienced CFAV, having joined the Campbell College Army Section in 1996, he has technically never left! Formally commissioning in 2004, he now holds the rank of Captain and undertakes the role of Training Officer, as well as assisting with national courses such as those at CTC Frimley Park and STEM Camp. With qualifications in exercise and range conduct, as well as skill at arms and first aid, they are at the frontline of cadet training and continues to draw on his experience to deliver safe and engaging cadet training to all age groups. All views are those of the author.

About Campbell College CCF

Campbell College Combined Cadet Force was the first such organisation established in Ireland in 1909. Starting life as an Officer Training Corps, many students served in both the First and Second World Wars, and continue to do so into the current day.