Compass with Magnetic Declination Adjustment

Higher end compasses allow for adjustable declination.  This makes conversions between Grid and Magnetic Azimuths so much easier.  One set up, you can use both grid and magnetic Azimuths without doing math!

First Adjust Declination

Look up the declination for where you will be traveling and when you will be traveling (magnetic declination changes). 

You can find up to date information here: NOAA Declination Calculator.

Note that Grid and True North may not line up perfect on your map.  This difference should be factored in to your magnetic declination since you are looking for the difference between your map's grid lines and magnetic north. 

Follow the instructions for Declination Adjustment.  This varies a bit from model to model.

Orient Map and Compass

Use your compass to orient your map so the grid lines line up with true north and south. 

• Center the orientation lines on your compass so they are lined up north and south.

• Rotate compass over maps so that the needle sits center in the "Doghouse"

• Rotate map under compass so that the orientation lines on compass line up with grid lines on map

• Now both the Compass and Map are orientated 

Measure Azimuth on Map

• Line up edge of compass on the azimuth you are interested in

• Rotate the orientation lines on compass to line up with grid lines on map

• Your Grid Azimuth is not plugged into your compass

Use Grid Azimuth to find Magnetic Heading

• Hold compass in front of you

• Rotate yourself so that that compass needle sits center in the "Doghouse"

• Your compass in pointing in the Magnetic Azimuth you set up

Follow you Azimuth

• Fold up map so it is easy to reference

• Keep the "Dog" in the "Doghouse" 

• Travel in you azimuth and reference map and pace count to keep on track

Magnetic to Grid

If you need to determine a Grid Azimuth using your compass, it is quite simple.

• Aim compass in direction/target you are interested in

• Rotate "Doghouse" until it is centered over "Dog"

• Recheck you are pointing in the correct direction

• Read dial - that's your Grid Azimuth

• To draw on map - line up Orientation lines with map, align edge of compass on your location and draw your line