Grid Magnetic Angle
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.
- 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.
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.