noun
- plural of isogone; lines on a map connecting points of equal magnetic declination (the angle between true north and magnetic north).
Usage: technical; geography/navigation
Examples
- Navigators use isogones on nautical charts to account for the difference between true and magnetic north.
- The isogones on this map show how magnetic declination varies across the region.
- Isogones help pilots and sailors correct their compass readings for accurate navigation.
- The spacing of isogones indicates areas where magnetic declination changes rapidly.