Isogonic lines are drawn on aeronautical charts to connect points having what characteristic?

Isogonic lines on aeronautical charts connect points that have the same magnetic variation. These lines represent the boundaries where the magnetic declination is uniform. Understanding isogonic lines is crucial for navigators because they help pilots determine the correction needed when converting magnetic headings to true headings.

Magnetic variation, or declination, is the angular difference between magnetic north and true north. When pilots are navigating, they must account for this variation to ensure accurate course plotting. By utilizing isogonic lines, pilots can easily identify areas where the magnetic variation holds constant, facilitating better navigation across large distances.

The concept of magnetic variation itself can differ across different regions, which is why isogonic lines are an essential feature on aeronautical charts for effective and safe flight planning and navigation.