Map, Compass & GPS

Map, Compass & GPS
Wild flowers along Fall Creek on the way to the Green Lakes - Oregon

Saturday, September 30, 2017

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.”

 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 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that map declination information be verified at   This is essential in the Pacific Northwest where maps are notoriously out of date in terms of road,  and city data.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.

Sunday, September 17, 2017

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.


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


  • 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.

Outdoor Quest Image
 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 .

·         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  (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. 

Saturday, September 16, 2017

Essential Camping Supplies for Your Outdoors Adventure

Are you new to camping?  If so then Lee has provided some nice recommendations for your considerations.

Camping is the perfect way to rejuvenate yourself by getting in touch with nature.  Before you begin your trip into the bush, you need to pack essential supplies to make the trip safer and more comfortable. This list of basics can help you decide what is a must-have for your vacation.

Food and Food Storage
A cooler with ice keeps fresh food safe to eat. Try freezing bottles of water at home, rather than using bagged party ice, to keep good fresher. Bottles won't leak water on your food like bagged ice, and bottles of water stay frozen longer than bagged ice.

You should also bring plenty of water for cleaning, drinking and waking up, a water reusable water bottle for each person in the group, and emergency, non-perishable food supplies like meal bars. Emergency food supplies are particularly important if you are camping in a remote area where medical help isn't readily available.

Lanterns and Personal Lighting
Torches, lanterns and other portable lighting devices are essential when camping. Choose lights that have LED bulbs for optimum brightness and improved efficiency, and bring along extra batteries to keep your campsite well-lit. In addition to lanterns, bring a headlamp for each member of the camping party. Headlamps allow you to easily walk through unfamiliar places and make nighttime chores much easier.

Campfire Alternatives
Along with pots and pans, you should bring asking a backup cooking device to prepare masks. Campfires aren't allowed during early summer, and total fire ban are in effect anytime the risk of fire is high.

To further improve fire safety, avoid throwing lit cigarettes on the ground while camping. Switching to a vape kit is an option that reduces fire risks in dry weather. You can find a vape starter kit page fit everything you need to easily make the switch while camping.

Garbage Bags and Cleanup Supplies
Everything you take into the bush must be carried out, making garbage bags a must-have for canning. Check your campsite thoroughly for even small pieces of garbage to keep the Australian Outback as pristine as it was before your arrival.

To prevent damaging the local environment, consider taking items that are environmentally friendly, such as biodegradable products and organic, biodegradable cleaning supplies. Reusable projects are ideal for both camping and home use.

Personal Supplies
Lip balm, baby wipes and other grooming supplies can make your camping trip more comfortable. Bring sunscreen along in both winter and summer to prevent sunburn, and pack moisturizer and lip balm to soothe your skin while camping during the winter months.

Extra Clothes
Proper attire is more important than you might think, so be prepared to bring the proper thing. Clothes that layer easily allow you to stay comfortable during cool nights ave hot days. Opt for natural materials like cotton or work, and pack a selection of both long and short sleeved t-shirts to comfortably layer.

Other clothes to pack include pants, shorts and a sweater or jacket. Don't forget to bring plenty of socks so you can keep your feet clean and dry throughout the camping trip.

Medical Supplies
A comprehensive first aid kit can be life-saving in an emergency, but also makes camping more comfortable when minor issues arise. Antihistamines, pain and fever reducers, bandages and daily prescription medicines are the foundation of your medical kit.

Add extra supplies based on the season, and take extra supplies if you are camping in a remote area. For instance, space blankets are a good addition when camping in winter, while water purification tablets are recommended when camping in more remote locations.

Customize your medical kit if children or people with health concerns are joining your group. With all the basic supplies on-hand, camping if an adventure that everyone can comfortably enjoy anytime of the year.

Monday, September 4, 2017

Escape or Shelter In Place

A few years ago I wrote a short post about Planing  Your Escape Route.  I recommended that when evaluating an escape route I suggested that the hiker consider several elements. 
First, take a look at your topographic map and tail guides to determine potential escape routes.  Evaluate the terrain.  Are there barriers due to slope and vegetation?  This is especially true should the hiker need to “bush whack” cross country.  A conversation with a ranger can be invaluable.

Right now my home state of Oregon is ablaze with wild fires.  Fires are everywhere.  Here is an overview of all the fires as of 8/30/2017.

Just recently over 100 hikers found them selves stranded as fire closed their trail and were trapped between blazes.  They have been rescued, they survived and they are lucky.