In the dialogue Magnetic Declination you can see the current Declination for your position. The function opens Open Street Map at your current position.
- Latitude/Longitude: Latitude and Longitude of your position.
- Magnetic declination: The angle between the direction of the magnetic meridians and the direction to the geographic North Pole at the observation site. With uncertainty factor and expected change per year.
- Grid convergence: The angle at the observation site between true north and grid north.
- Grid magnetic angle: The difference between the two values above, by how much the map should be rotated.
You can only Apply the Angle, if no objects have been drawn yet. If you have already drawn objects, use the Rotate Map to Magnetic North function instead.
More information about Declination can be found in this Blog Post.