MagVar is a small program for computing magnetic variation and great circle course and distances for any part of the earth between 80 degrees north and 60 degrees south.
Our Review: Left-click in the middle of the map and you can draw spirally patterns by right-clicking in circles! The map could be of a higher resolution but four stars must be given simply because I've never seen another program like it. Definitely one for the computer-literate mariners among us.