Map, Compass & GPS

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

Wednesday, April 26, 2017

Plot Your Position With a Compass


 A quality compass is an integral part of the backcountry navigator’s kit.  Sighting with a compass is an important skill that can determine direction to an object or help the hiker locate and identify his position in the backcountry.


This post discusses the steps to be taken to use a compass to plot one’s location on a topographic (topo) map in the back country.  In the vocabulary of navigation this is also known as “fixing” or determining “position.”

The first step is to ensure that the hiker has adequate maps both in quality and quantity.   I recommend carrying a set of maps that include 7.5’ United States Geological Survey (USGS) maps and a second map type such a United States Forest Service map.  The USGS map gives me the detailed information of the immediate area while the other map covers a much broader and larger area. 

Before heading for the trail, take a look at the maps at home.  Scouting from your desk allows you to find significant land features that will surround the direction of travel.  Features such as distinct mountain peaks, a stream, and a ridge line are just of few topographic “hand rails” that can be of value in the field.  By spending some time at home with the map the hiker develops a mental map, a mental picture of the trek in advance of the actual journey. 

Account for declination before leaving the trailhead.  I like to keep my navigation simple and personally use a compass that can be adjusted for declination such as the Brunton 8010G.  Declination information found at the bottom of a topographic map is frequently out of date.  Check the web site www.magnetic-declination.com  for the current declination.



 “A compass is basically a magnet mounted on a pivot, free to turn in response to the pull of the earth’s magnetic field.  The housing protects the needle and helps you relate the direction in which the needle points to directions on the map and on the land.  A compass by itself can’t tell you where you are or what you are looking at but it can tell you about direction….”

Staying Found, The Complete Map & Compass Handbook, by June Fleming

Sighting with a compass allows the hiker to do several things.

First, sighting on a distant object can provide direction to that object and repeated sightings can provide course corrections along the way.  Secondly, with several sightings on different objects a person’s position can be determined and plotted.

Compass direction to an object is known as the “bearing” or azimuth.   Bearing is the more common term in outdoor recreation and is a term used heavily in GPS navigation.  For example, if a mountain peak is due north of you, the bearing to the peak is 000° (read as zero zero zero degrees.)  A compass can also assist the hiker by orienting a map and following a line of bearing taken from a map.

The picture below offers a quick review of the components of a baseplate compass.


To sight or take a bearing do the following:

  1. Using the owner’s manual, adjust the compass for declination.
  2. While holding the compass at waist level, turn squarely towards a distant object.  Hold the compass so that the direction of travel arrow points directly at the object. (Point the direction of travel arrow away from you, perpendicular to your body.)

  1. While holding the compass, turn the compass housing (the dial) and align the orienting arrow (a red arrow engraved in the rotating housing) underneath the red magnetic needle.


 To determine and plot or “fix” a position, the next step is to plot bearings on the map. In a “nut shell” this means that bearings to three clearly identifiable features are used.  Ideally, objects that have a bearing separation of 30° – 60°.  Good bearing separation provides better fixing information and plots on the map cleanly.  The bearings are then plotted on a map and where the three lines cross is the hiker’s location.  This complete process is called triangulation.

The following are suggestions for triangulating a position in the back country.

  1. Identify three (or more) distinct objects to sight on.  Note that the objects need to be on the topo of the area. 
  2. Orient the topo using the compass.  Orienting the topo means that the map’s left or right border is pointing to true north or 000° degrees true. 
  3. Sight on an object such as a mountain peak or church spire.  (Note that not many objects in the backcountry are so distinct and crisp.  Do the best with what you have.)  Ensure the direction of travel arrow is pointed towards the object.  Be as accurate as you can, point directly at the object.
  4. Turn the compass housing until the orienting arrow is directly under red magnetic needle.  Do not move or rotate the compass housing, keep the new bearing in place.
  5. At this point, and while plotting the bearing on the map, the compass will now be used like a protractor.  Importantly, the movement of the magnetic needle is not important.
  6. Lay the compass on the map with either the top left or right corner of the baseplate on the landmark.  This will be a pivot point while aligning the compass.


  1. With the edge of the baseplate in position, rotate the compass (swing) left or right until the N (north) of the compass housing aligns with map North (the top of the map.) 
  2. Draw a line (along the baseplate) from the object (e.g., the mountain peak) to your approximate area.  Draw a nice long line.
  3. Repeat the process two more times using other distant objects to sight on.
  4. Ideally the three lines will intersect in the immediate area; this is the hikers location.  But because of compass error and human error the point of intersection maybe spread out.  Still, triangulation will put you in the ballpark.  Use terrain association to help narrow down your position.

   

Sunday, April 23, 2017

Extreme Weather Survival

Wes Siler recently wrote a fine article in OUTSIDE magazine titled "The 5 Principles of Extreme Weather Survival." 

The key take-aways of this article are the subtitles:


  1. Never Leave Home Unprepared.
  2. Check the Forecast
  3. Tell Someone Before You Go
  4. Be Conservative
  5. Use Common Sense
Do visit my website to download a copy of my trip plan.  This is akin to the pilots flight plan.

Remember the phrase, "the devil is in the details."  Well, Search and Rescue teams deserve as much detail as you can provide. 

Check out Wes Siler's article.  It is certainly worth your time.



Wednesday, April 19, 2017

Getting Accurate Compass Readings




I found these recommendations a while back when I was researching techniques for using a magnetic compass.  A small error when using a compass can result in a significant error in measurement on the ground.


To obtain accurate readings when using a compass:

  • Ensure the compass has been adjusted for declination. 
  • Hold the compass level and steady so the needle swings freely.
  • Hold the compass about waist high in front of the body, except when using a compass with a sighting mirror or a sighting type compass.
  • Raise and lower eyes when taking a bearing, do not move your head. Always use the same eye when taking bearings.
  • Directly face object that is being measured.
  • Magnetic fields will give incorrect compass readings. Avoid taking readings near magnetic fields such as steel, iron (ferrous metals), vehicles, rebar, and clipboards. Even belt buckles, glasses, and rings can interfere with the compass reading.
  • Take bearing twice. 
  • Adjust for magnetic declination as appropriate.
  • Follow the direction of travel arrow, not the compass needle, when walking a bearing. Always follow the line indicated by the compass rather than relying on judgment as to the direction.
  • Use back bearings to ensure you are on track when navigating.

Saturday, April 15, 2017

Plan Your Escape and Evacuation Routes



Planning Your Escape Route

Alternative and escape routes - Once you have planned your route, plan and check out alternative routes that you may need to take in case of bad weather or if the going gets too much for some party members. In mountainous areas, it is essential to have two or three detailed escape routes should any situation or emergency arise.”







Over the last several years my Search and Rescue (SAR) team has participated in several forest fires operations in Oregon.  The team has helped to coordinate the evacuation of small community neighborhoods and has worked with Forest Service staff to assist stranded hikers.  Getting these hikers out safely has been a priority.  Many hiking groups were met by local Ranger District staff well away from the fire to plan their exit.  Others self extracted.
Thankfully, there have been no personnel casualties.



As bad as this fires have been, there have been several lessons learned.  One has been to plan an escape route.  Develop the plan at home before hitting the trail.

The threat to the hiker ranges from fire, weather (snow, rain and wind) to a geologic event (earth quake).





When evaluating an escape route I recommend 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.


Second, is the route achievable and realistic for you and your group?  Is your group fit, healthy and ready for such a hike?  


Third, are there sources of water along your route?  In some cases blue stream lines on a topographic map should be colored brown in the summer as stream beds dry up.


Forth, carry the right gear?  Does the day hiker have the ten essential in the pack?

Communicate your change of plans to friends and family.  Let that responsible person (designated to call 911 if you are late) know your plans too.


Don’t forget to fill out the trail permits when traveling in the backcountry.  These are invaluable to narrow down who was still in the backcountry.  In several cases, contact numbers were called to verify the safe return of a hiker.  Take this seriously.  One fellow used the Portland Airport designator (e.g., PDX) as the home address.  This was not helpful.


Thursday, April 13, 2017

Keeping Yourself in Shape for Your Next Backpacking Trip


A new post by Lee.


If you have a big backpacking trip planned for the near future, you definitely want to be in the kind of shape where you can enjoy it. You won’t have nearly as much fun if you’re huffing and puffing after the first mile. It doesn’t take training like Rocky to be ready for backpacking, as all you need to do is follow a few simple steps to keep yourself in good condition.

Go on Walks, Runs, and Hikes

The best way to train for a physical activity is to mimic that physical activity as closely as possible. For backpacking, your best option is going on hikes while wearing a backpack, since that’s exactly what you’ll be doing on your trip. Do this frequently enough in the weeks and months leading up to your trip, and you shouldn’t have any issues.

You may not be in a situation where you can hike much, if at all, depending on where you live and the weather. If that’s the case, running and walking are both good alternatives, with running being better since you need to work harder. You can wear a backpack or substitute it with a weight vest so you still get the feeling of carrying weight.

Stick to Healthy Eating Habits

What you eat is a huge part of your overall health. The key to eating healthy is to make it part of your lifestyle, instead of looking at it as a diet. If you don’t currently have the best eating habits, start substituting healthier food choices one meal at a time. By changing your eating gradually instead of all at once, it’s easier to commit to the changes.

As far as what you should eat, you should focus on natural foods, which means anything that comes from an animal or the ground. Healthy food choices include lean meats, fruits, vegetables, and whole grains. You can usually find the natural foods towards the outer edges of a supermarket, while the processed junk food will be concentrated in the center aisles.

Work on Any Bad Habits

If you’re smoking a pack a day or drinking heavily, it’s going to be nearly impossible to get in good shape for your backpacking trip. One different alternative to tobacco is vaping. You may find that getting a vape helps you cut back on cigarettes. The nice thing about vaping is you can try all kinds of different flavors. Online sites like the e cig juice page from Halocigs can give you a variety of many flavors you can check out.

When it comes to drinking, alcohol isn’t an issue if you use it in moderation. If you find that your drinking is getting out of hand, you may want to commit to staying sober for a certain amount of time or at least cutting down on your alcohol intake.

Get Enough Rest

Make sure you don’t push yourself too hard to the point where you end up injured or burnt out before it’s time for your trip. Whenever you start a new workout routine, take it slow and gradually build up to higher frequencies and intensities. Get at least six to eight hours of sleep every night, as that’s when your body will dot the bulk of its recovering.

If you start feeling very tired or sore, that’s a sign that it’s time to slow down. Take a couple days to let your body recover from everything. You may also want to do some lighter intensity work, such as yoga, on occasion. Remember that you want to be at your best for your trip.

The sooner you start preparing for your backpacking trip, the better. In the leadup to your trip, try to get a workout in at least three or four days per week. Eat healthy, reduce those bad habits, and rest up so you’ll be ready to go when it’s trip time.


Friday, March 31, 2017

Finding Remains in the Field


At a recent Search and Rescue (SAR) conference I sat through an excellent presentation by the state of Oregon's medical examiner.

She offered her suggestions regarding the discovery of human remains in the field.

First, don't move the remains or other items such as clothing, shoes and other personal effects.  You may have found a crime scene.

Second, take a picture of the bone that is found.  A cell phone camera is fine.  Put a reference to determine size for the examiner.  For example, a ruler works best but the sole of your boot or a knife would help too. 



Use your GPS to  record the geographic coordinates of the scene.

Consider marking the location with flagging tape.

Contact and forward the image to the local law enforcement authorities.

The image below says it well.






Wednesday, March 29, 2017

Handrails

In a previous post I discussed the concept of terrain association.  Terrain association is the process of visually confirming a map to land features.

A subset of terrain association is the use of handrails.  Handrails are linear features found on a map and visually correlated to observed land features.  In a building, a stairway’s handrail provides direction for a walkers travel down to another level.

Examples of handrails include roads, rivers, trails and railroad beds.  Handrails can be particularly useful when they run parallel to ones’ direction of travel.



Highway 126 and Cache Creek are distinct linear features that could serve as a handrail.
In the map above notice that the red direction of travel line parallels Highway 126. 

In this example Highway 126 could also be a backstop to alert the hiker that crossing the roadway would take them in the wrong direction.

Be alert for a handrail’s change of direction.  There may be prominent land features that will alert the backcountry traveler to such a change.  A butte or building might be adjacent or near to a change in direction.