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The Compass Rose

The compass rose is found on all navigation charts. The most obvious job of the compass rose is to point to true north. True north is where the meridians end which co-insides with the North Pole. This is indicated by the outer ring of the compass rose. The inner ring of the compass rose contains your magnetic heading. The magnetic north pole is not located exactly at the North Pole. The closer one gets to the North Pole the greater the error factor. This error factor is called magnetic variation. If your look carefully at the center of your compass rose, you will see that the magnetic variance is known for your location. Also, that it is a constant number that must be added or subtracted from the true numbers one finds on the chart. Hint: if the numbers on the inner ring are greater than the outer ring we must add the variance to all our calculations to get a compass heading. If the numbers on the inner ring are smaller then we do just the opposite and subtract the magnetic variation to get our compass heading.

Mark your Magnetic Variation on the space provided on the Charting Pal so you will always have it close at hand.