Which line type connects points with the same magnetic variation?

• A. Isogonic lines
• B. Isobars
• C. Jet route
• D. IVSI

Answer: (A)

Magnetic variation is the angular difference between true north and magnetic north, and charts use lines to show where that difference is the same. The line type that connects points with the same magnetic variation is called an isogonic line. These lines let pilots know where a constant correction between true and magnetic headings is needed as you fly over the area, since the variation doesn’t change along an isogonic line.

Why the others don’t fit: isobars connect points with equal atmospheric pressure, jet routes are predetermined high-altitude airways, and an IVSI is an instrument that indicates vertical speed, not a map feature.