what is the meaning of grid magnetic angle

The grid magnetic angle refers to the angle between true north and magnetic north as measured on a map or chart with a grid system. When we use a map or chart for navigation purposes, we need to take into account the variation in magnetic declination, which is the difference between true north and magnetic north. This variation can vary depending on the location and can cause discrepancies in navigation.

To avoid these discrepancies, we use a grid magnetic angle, which allows us to offset the compass reading by a certain amount to account for the magnetic declination. This offset allows us to more accurately navigate and avoid any potential errors.