How do true north, magnetic north, and declination affect compass use in SAR?

How do true north, magnetic north, and declination affect compass use in SAR?

• A. They are identical in all locations
• B. True north is geographic; magnetic north differs; declination is the angular difference requiring adjustments
• C. Declination is fixed and never changes
• D. Only true north matters for navigation

Answer: (B)

The essential idea is that navigation references two different norths and you must account for their difference. True north is the geographic north line toward which all maps and geographic coordinates are aligned. Magnetic north is where the Earth's magnetic field currently points, and it moves over time and varies by location. The angle between these two directions at your position is the magnetic declination. Because SAR work often uses maps oriented to true north while your compass points toward magnetic north, you have to adjust for this declination to navigate accurately. In practice, if declination is east, magnetic north is east of true north, so you add that east declination to a magnetic bearing to get a true bearing. If it’s west, you subtract. This adjustment lets you translate compass readings into map directions (and vice versa) so your search pattern lines up with the map and terrain. So the correct answer states that true north is geographic, magnetic north differs, and declination is the angular difference that requires adjustments—which is exactly what you must do to use a compass reliably in SAR.

The essential idea is that navigation references two different norths and you must account for their difference. True north is the geographic north line toward which all maps and geographic coordinates are aligned. Magnetic north is where the Earth's magnetic field currently points, and it moves over time and varies by location. The angle between these two directions at your position is the magnetic declination.

Because SAR work often uses maps oriented to true north while your compass points toward magnetic north, you have to adjust for this declination to navigate accurately. In practice, if declination is east, magnetic north is east of true north, so you add that east declination to a magnetic bearing to get a true bearing. If it’s west, you subtract. This adjustment lets you translate compass readings into map directions (and vice versa) so your search pattern lines up with the map and terrain.

So the correct answer states that true north is geographic, magnetic north differs, and declination is the angular difference that requires adjustments—which is exactly what you must do to use a compass reliably in SAR.