Isogonic line

isogonic line
a line drawn on a map or chart joining points of equal magnetic variation
ISVT ...

isogonic chart Chart showing isogonic lines properly labeled with their magnetic declination. isogonic line Line joining points on the Earth's surface having equal magnetic declination as of a given date. isopleth map See: map, isopleth ...

Isogonic lines are lines connecting those parts where the declination of the Earth's magnetic field is the same in amount. They are similar to isoclinic lines, which are lines connecting points of equal magnetic inclination.

See also: Cover, Record, Weight, Survey, Server