On a map, what does the Declination Diagram indicate?

On a map, what does the Declination Diagram indicate?

• A. The angle between true north and magnetic north
• B. The map scale
• C. The symbols used in the legend
• D. The size of the grid reference box

Answer: (B)

The main idea is that the Declination Diagram shows the difference between true north and magnetic north at that location. It gives the angle by which a compass needle is off from geographic north, and it usually indicates whether magnetic north lies east or west of true north. This matters when you’re navigating with a map and a compass. If the declination is, say, 12 degrees east, magnetic north is 12 degrees to the east of true north. To move so your map direction matches your compass reading, you adjust by that amount: add the declination to your compass bearing to get the map bearing. If the declination were west, you’d subtract it. So the diagram isn’t about how far apart your map is in scale, nor about the symbols in the legend, nor the size of any grid box—that information comes from other parts of the map. The Declination Diagram specifically helps you reconcile compass readings with map directions by showing the angular difference between true north and magnetic north.

The main idea is that the Declination Diagram shows the difference between true north and magnetic north at that location. It gives the angle by which a compass needle is off from geographic north, and it usually indicates whether magnetic north lies east or west of true north.

This matters when you’re navigating with a map and a compass. If the declination is, say, 12 degrees east, magnetic north is 12 degrees to the east of true north. To move so your map direction matches your compass reading, you adjust by that amount: add the declination to your compass bearing to get the map bearing. If the declination were west, you’d subtract it.

So the diagram isn’t about how far apart your map is in scale, nor about the symbols in the legend, nor the size of any grid box—that information comes from other parts of the map. The Declination Diagram specifically helps you reconcile compass readings with map directions by showing the angular difference between true north and magnetic north.