adjective
- of or relating to lines on a map connecting points of equal magnetic declination
Usage: technical; geography/navigation
Examples
- Navigators use isogonic lines to account for the difference between true north and magnetic north.
- The isogonic chart showed how magnetic declination varies across the region.
- Pilots must understand isogonic maps to fly accurate headings.
- An isogonic line connects all points where the magnetic compass points in the same direction relative to true north.