A Compass Tune-Up

Recently I was watching a rifle expert on one of the many outdoor cable shows.   This gent is a noted ballistics expert, writer and occasional backcountry guide.  During a segment of the interview he was demonstrating what was in his day pack.  It kept my interest, had the Compass practice in a navigation class  Outdoor Quest image ten essentials, and all was going just fine until he brought out his compass.  It looked like a wonderful antique, might have come across the Great Plains and Rockies with Lewis and Clark –but in terms of reliability-it was questionable. The sad part is he spent absolutely no time discussing key factors of having a reliable compass.  He touched his compass and quickly put it down.  And touching a compass is about all that most people do too.  Hunters preparing to go afield will spend hours with their rifle at the range evaluating their zero, adjusting optics, and measuring the initial velocity of that hot new round.  Navigation takes time to get dialed in too. Navigation is not “rocket science” but it takes practice.  It is a perishable skill.  The analogy that I use in my wilderness navigation classes is that you can hop on a bike after not riding one for ten years and head on down the road.  But trying to triangulate after ten months can be a chore.  For starters, you need a decent compass.  Leave the $5.00 compass on the shelf at the store.  For more information on buying a compass check out my article on selecting a compass. Here are a few recommendations for a compass tune up: ·     Store your compass in a safe spot.  Keep the compass off the dash of the rig, away from flashlights and the GPS.  Let’s not take a chance that an electrically induced magnetic field will degrade your compass. ·     Compare your compass with another to verify that the red needle is pointing to magnetic north.   Take it a step further and find a road in town that is aligned north/south.   Most likely it will be aligned in degrees true; as in true north.  Again, verify that the compass is pointing correctly.  Do this for every compass you own. ·     Is the compass leaking?  Is there an air bubble floating in the compass housing?  I “deep six” (toss) those units. ·     Brush up on your compass navigation skills.   June Fleming’s book “Staying Found” is a excellent read.     Practice shooting a bearing, triangulating your position and orienting your map and compass to your surroundings. ·     Review the components of a Topographic map.  Start with the USGS’ site here. ·     Insure you have the compass adjusted to the correct declination. ·     Practice with your children.  Give them a good education with a map and compass before you give them a GPS. ·     Don’t depend on your friends being the navigation experts.  Make it a goal to exceed their skills.  You might find that your initial impression was mistaken. Instead of a “sense of direction” develop the skill of navigation. Practice with a compass is essential to safe wilderness travel.  To quote Fleming, “The key to knowing where you are is constant awareness.”

Maps for Emergency Evacuation

My friend Leon at the blog www.survivalcommonsense.com has a great post on the maps you should have during emergency evacuation. 

Adventures In Stoving

You have to just like Hiking Jim's blog "Adventures in Stoving."  This is a blog to book mark.


Right now he a has a post reviewing a stove system and a methodology on how to determine how much stove fuel to take in to the back country.


Great  work.

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Using Your Cell Phone In The Backcountry

Last month Jenny Rough wrote an interesting article about why it is a mistake to count  on a cell phone when you go hiking.  Her article was featured in the Washington Post.

She stressed that basic navigation "is a use-it-or-lose-skill.  How true.

The thrust of the post is that hikers have an over dependence of electronic navigation while forsaking the rudimentary  principles of using a map and compass. 

Take a look at Jenny's post.

Visit my other articles on land navigation too:

• Compass Tips
• GPS Tune-up
• Terrain Association

• A Hiker's Trip Plan

What Is An Azimuth

An azimuth is the angular direction to an object.  Azimuths are described commonly in degree increments from either true, magnetic or grid north.

In the world of recreational navigation, GPS receiver operations and orienteering the use of the term “bearing” has become synonymous with azimuth.

Azimuth direction is measured from north clockwise in 360° increments. The point from which the azimuth originates is from the center of an imaginary circle.  This imaginary point is the operator.

Azimuth can be measured with a magnetic compass, a map and by rough estimation using the sun and North Star.

Azimuths can be expressed in degrees true and degrees magnetic.  Degrees true uses the north pole as the principle reference while degrees magnetic refers to reference from the magnetic pole.

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For more information on bearings and azimuth read Making Sense of The Declination Diagram.

Magnetic Declination

“Declination: A Noun. The horizontal angle between the true geographic North Pole and the magnetic North Pole, as figured from a specific point on the Earth.” www.dictionary.com

 Declination is a term that causes “brain cramps” for many of my students in my map and compass classes. When I mention Magnetic Declination eyes roll.

The web site www.magnetic-declination.com has an excellent discussion of what declination is and what causes it:

“Magnetic declination varies both from place to place, and with the passage of time. As a traveler cruises the east coast of the United States, for example, the declination varies from 20 degrees west (in Maine) to zero (in Florida), to 10 degrees east (in Texas), ......the magnetic declination in a given area will change slowly over time, possibly as much as 2-25 degrees every hundred years or so.......... Complex fluid motion in the outer core of the Earth (the molten metallic region that lies from 2800 to 5000 km below the Earth's surface) causes the magnetic field to change slowly with time."

Land navigation is based on the relationship to the North Pole; also known as “true north.  The measure of degrees of direction in relation to true north is called “degrees true.”  Maps are laid out in degrees true.  Land features (buttes, mountains, streams) on a topographic map are in reference to degrees true.  By that I mean the bearing from one mountain peak to another will be referenced in degrees true.  The map below illustrates that point. 

Magnetic compasses do not point to true north (the North Pole); the magnetic needle points to an area that could be considered the magnetic North Pole. 

As illustrated below, declination data can be found in the diagram at the bottom of a USGS topographic map, (on some commercially produced maps it can be hard to find.) 

Because declination changes over time, I recommend that map declination information be verified at www.magnetic-declination.com.   This is essential in the Pacific Northwest where maps are notoriously out of date in terms of road,  and city data.

So, how do we make this simple?  How do we convert magnetic to degrees true?

I could do the math.  In Oregon, where I live, the magnetic declination is 15.6° East declination.

My recommendation: have the compass do the work so that there is no confusion with the math.

To do this, I need to choose a compass that can be adjusted for declination.  Examples are the Silva Ranger or the Suunto M3.

With one of these compasses, the compass dial or housing is adjusted and rotated manually.  Both the Suunto and Silva Ranger come with a small, flat adjusting tool.  Consult with owner’s manual that came with the compass.

If declination is Easterly (Western U.S.) I will rotate the dial causing the baseplate’s orienting arrow to move in a clockwise direction.

   If declination is Westerly (Eastern U.S.) I will rotate the dial causing the baseplate’s orienting arrow to move in a counter-clockwise direction.

Now, adjust the dial and align the red magnetic needle on top of the orienting arrow (the red arrow engraved on the baseplate) the compass will provide directions in degrees true.

GPS Tune Up

Hunters, this is a great time to tune-up and practice with a GPS receiver.  There are several things the one can do before leaving home.   Here are a few recommendations to consider.

Setup

• Dump those old AA batteries, put in new ones.  If you leave your GPS on all day in the

  

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    field expect to change the batteries nightly.  Consider using lithium AA’s, they last longer and work better in cold temperatures. 

• “Match the map” with the receiver’s navigation selection options. Specifically, match the coordinate system (e.g., UTM or Latitude/Longitude) and map datum that are found on the map.  Consider shifting the receiver’s compass to degrees true.  Further, let’s have everyone in a hiking or hunting group use the same settings too; let’s all be on the same page.

•  Keep you navigation simple.  It’s easier to work with a handful of waypoints rather than list of 300.  Dump the Junk - Delete the old waypoints, the ones you will never use again.  Log important waypoints (e.g., that lake side camp site) on your PC or in a notebook.  Visit www.easygps.com or www.garmin.com for a place to store waypoints.

• Install maps on your GPS receiver.  Maps on the receiver are a natural complement to your paper field map.   Quality maps are available from onxmaps.com and GPSFiledepot.com (free).

• Adjust your map pages’ zoom setting to see what works best.  For general trail hiking I  keep my zoom setting at 800 feet.  This setting allows me to view trails, water sources, roads and elevation contours.

• Visit the manufacture’s web site to see if there are any firmware updates.  I do this every couple of months.

• When batteries are replaced calibrate the electronic compass.

Tune-up

• Verify that you are receiving enough satellite signals.  Check this on the satellite status screen.  Four satellites are the minimum.  Give older receivers the time to collect satellite data; don’t rush the navigation process.

• Give key waypoints names.  When marking a waypoint enter names like “camp” and “truck.”  It’s easier and more meaningful to find “truck” in the list of waypoints than is waypoint 542; or was it 245.  

·        After marking a waypoint, verify that it has been saved to the receiver's memory by checking either the map page or in the waypoint file (select “where to” or “find.”)  If the waypoint is on the map or in the list of waypoints, the hiker is ready to go.  If the waypoint is not found, start over.

·      

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 When it’s time to return to a destination chose “Where To” or “Find” on your keypad or menu.  Select the waypoint from the list provided.  Press the “Page” button and rotate through the many displays to the “Compass” page.  A large red arrow should appear on the face of the compass pointing to the selected waypoint.  When on course to the destination the arrow points to the top center of the receiver.  Practice this specific process at home before heading to the field.

• Navigation is a perishable skill.  I recommend that two weeks before an outing take the GPS receiver everywhere.  Add waypoints, delete waypoints and find a saved waypoint.  This process develops familiarization with the unit and allows the user to develop confidence with the receiver      and personal ability.

• Compliment GPS skills with a good review of map and compass fundamentals. Learn to back up electronic position fixing with bearing triangulation.   Worst case, a broken GPS becomes a paperweight for your map while afield.  For more information visit www.outdoorquest.blogspot.com .

·         When on the trail compare GPS position data with a map.  Compare what is presented electronically with what is on the map.

I suggest checking out Lawrence Letham’s book GPS Made Easy from the library.  This book compliments the owner’s manual.  An excellent reference for map and compass use is June Fleming’s Staying Found.

Taking a class can further enhance you GPS knowledge.  Classes are frequently offered through the local community college’s continuing education program or at local retailers such as  REI.

A map and compass always goes with me into the field.  I carry a Silva Ranger compass and get my maps from Caltopo.com  (their maps are free.)

Have fun while building on your fundamental navigation skill sets.  Consider setting up a treasure hunt or a geocach for a family get together.  Make it fun, make it simple and explain that these skills could one day make a huge difference if the ever got lost in the woods.