Map, Compass & GPS

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

Saturday, March 21, 2015

Evaluating Back-Up Magnetic Compasses

Frequently in my backcountry land navigation class, I am asked about the need to carry a back-up compass.  Generally students are interested in a light weight model that is low in cost, small in size, and would “fill in” as needed. 

I purposefully evaluated several models many consider to be back-up options.  When choosing a back-up magnetic compass, the hiker must ask himself “What are my priorities?  Is it accuracy? Reliability?  Cost?  Size and weight?”

Different models bring different values to the outdoorsman.   If the primary compass got crushed, misplaced, or stopped working what model would serve as a back-up to get out of the woods safely?  Generally a back-up compass isn’t as capable as the primary.  People want to cut back on weight and expense.
For this evaluation, I selected five commonly used compass models.  They are: the Brunton 9020G, a wrist watch compass “The Navigator” (sold by Country Comm), the Silva Type 3, the Silva Type 7, and a ball compass by Outdoor Product (not Outdoor Research.)
 I will compare the five selected back-up units to the highly regarded Silva Ranger (CL 515) and Brunton 8010G base plate compasses to establish a bearing standard. The Silva ranger and 8010G models are oriented to magnetic north as shown below:



Figure 1   The Silva Ranger (left) and the Brunton 8010G (right.)

Neither the Silva Ranger nor Brunton 8010G are adjusted for declination for this review.   This provides a consistent baseline for evaluation purposes. 

To begin the comparison of the back-up compass models, I chose to define them in the categories of (1) reliability (2) accuracy and readability (3) cost and (4) size and weight.
Reliability:

I picked up each back-up compass model option and turned it in place rotating the compass and magnetic needle.   I then stopped and set it on a flat surface oriented to magnetic north.  I quickly found that the Brunton 9020G, and the Silva type 3 and 7 settled quickly and matched the bearing of the standards.  The compass needles quickly aligned to magnetic north and required little movement on my part to stabilize the compass.

The ball and wristwatch compasses were extremely finicky.  Both models required time and manipulation (moving the compass housing side to side, up and down) to get them to align to magnetic north.  Both required what I consider to be excessive movement to level the housing to allow the needle or ball to swing freely.  This was especially true of the ball compass; frustrating.
Figure 2 Compasses from left to right: The Brunton 9010G, The Navigator, Outdoor Product ball compass, Silva type 7 and type 3.  Note that the five compasses close proximity to each other cause the magnetic needles pointing in different directions.

Accuracy and readability:

I then checked the compasses for their alignment to magnetic north.  All models were in general agreement but the three baseplate compasses ( Brunton 9020G, Silva Type 3, Silva Type 7) allowed for a more accurate reading with 2° increments marked on the rotating dial.  Further, each baseplate compass could be used for sighting on a distant object to triangulate the hiker’s position.

The ball compass and the watch compass did not provide for accurate measurement; they just aren't built for that.  The Navigator has increment tick marks every 10° and the ball compass is marked every 15°.  That said, both will provide a trend of direction. Knowingly choosing a trend of direction verses specific bearing accuracy is a critical choice for the outdoorsman when selecting a back-up compass model.  The impact of providing a trend of direction is that these compasses will indicate that the hiker is moving in a generally northerly direction as opposed to hiking along a bearing of 350°.

Cost:

The most affordable are the ball compass ($2.00) and the Navigator (under $5.00).  The three baseplate models range from $10 to $12.

Size and Weight: 

The wrist watch Navigator is the most compact and is read quickly.  Having a compass on the wrist takes a bit getting used to; it’s just different.  The ball compass is most frequently worn on the exterior of a jacket or on a pack’s web gear.  Both are quickly accessible and are feather light.  

The Brunton 9020G is the largest of the group.  That said, all three baseplate compasses fit easily in a shirt pocket.

Size and weight is of minimal concern for all five models.

The ball compass and Navigator are fine for short day hikes.  Both are good choices as an introductory model and get young people interested in navigation early.


For serious backcountry adventures I’d opt for one of the baseplate models.  The 9020G ability to adjust for declination is a big plus for me.  The baseplate models are the natural progression for learning the finer points of compass navigation.

Wednesday, March 18, 2015

What Maps to Take Hiking

Seattle Backpackers Magazine recently published my recent post about what maps hikers should take into the backcountry.

"In a recent map & compass class, one of my students asked me what maps I carry into the backcountry when hiking or hunting. In this piece, you’ll get all of the info you need to learn what maps to take hiking on your next adventure."

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Tuesday, March 17, 2015

Navigation While Hiking in a Group

Check out my latest post featured on sectionhiker.com.

This post is all about hiking with your friends.  I provide a list of recomendations to keep you navigation on track.

Monday, March 9, 2015

Topographic Map Symbols


Colors and symbols add the detail unique to a topographic map.  These details may not be found in gazetteers or travel guides.  Map detail includes important information about elevation, water, structures, trails, ground cover and roads; and much more.

 “The mapmaker has been forced to use symbols to represent the natural and man-made features of the earth’s surface.  These symbols resemble, as closely as possible, the actual features themselves as viewed from above.”

                                                                        U.S. Army Field Manual FM 21-28                                                                                                     Map Reading and Land Navigation, 1993

Topographic maps are rich in symbols.  Specific to a location, symbols identify features such as buildings, springs, bench marks, mines and bridges.  The United States Geologic Survey’s (USGS) guide Topographic Map Symbols is four pages long and lists dozens of symbols.  To view the USGS’s complete listing go here.

The following graphics are a sampling from Topographic Map Symbols.  The symbols below are those used for rivers, lakes and canals.  Note the different colors used.
The graphic below illustrates symbols related to buildings and other man-made features.



Note that the color of these symbols is predominantly black.


Let’s highlight a few symbols that the backcountry hiker will find helpful (the symbol will be listed to the left.)

 Bench Marks are survey monuments.  Location and elevation data is accurate.   Bench Mark will be represented by the letters BM and next to it will be printed the elevation data; see map above.  In the backcountry, Bench Marks will have a brass/bronze plate at the location to identify the mark and its position data.  Please do not tamper with a Bench Mark.


A trail is highlighted in the map above.  Trails are black dashed lines.


     Useful to the hiker are four wheel drive roads (4WD) and unimproved roads.  These are commonly called jeep roads and may be usable on foot, horseback or mountain bike.  Some of these roads may not be passable by vehicle.           

Thin, powder-blue lines represent streams.  What looks like a dashed blue line (right half) represents an intermittent stream; a flow that may disappear in dry weather.


I recommend spending some time browsing through Topographic Map Symbols and to become familiar with the symbols listed. The web site www.landnavigation.org provides a fine review of colors and symbols that are linked to photographs.

Monday, March 2, 2015

Land Navigation


Navigation Term of the Week*
Outdoor Quest Image

Heading – A direction of travel.  For example, the hiker traveled on a northerly heading to the cabin.  Heading is expressed in degrees measured from North clockwise to the direction of travel.
Outdoor Quest Graphic





















* or maybe the month - we'll just see.

Saturday, February 28, 2015

Hiking With Children

The following highlights an article by the Statesman Journal writer Zach Umess.  It's all about hiking with children, really small children.  

"Once upon a time, going for a hike was a simple activity.

Toss a few snacks, water and appropriate gear into a backpack, lace up your hiking boots, and you're ready to roll.

That all changes once you have children.

Between diapers, changing pad, spit-up rag, food, toys, carrier, clothes — and a few million other items you'd never even considered — it can feel as though you're outfitting a small army rather than a tiny human being.

And that's without even considering your child's mood.

Taken together, it can be difficult for parents, especially new parents, to get out on the trail.
But a group called Hike It Baby, which recently opened a branch in Salem, is encouraging new parents to get outdoors by offering a supportive atmosphere on organized weekly hikes."

Zach Umess really get's into the detail of this group.  It's worth checking out the rest of his
fine article.

Tuesday, February 24, 2015

Trip Planning Mistakes

Philip Werner at sectionhiker.com published this post in 2014.  My friend Peter who is planning for a PCT hike forwarded this on to me.  Lots of lessons learned in this fine article.



"When Wysteria, Sherpa, and I arrived at the trail head we found 4 foot snow drifts covering the trail. It was late March, and we’d planned to backpack north over Mt Greylock past the Massachusetts/Vermont border. We knew that there might be some lingering snow in the early spring, but we had no idea winter would still be in full force. Scratch that trip.
I’ve since learned to wait until mid-April before hiking the AT in Western Massachusetts, Vermont, and New Hampshire for lingering winter snow to melt off."

Read the rest to Peter's post to read the Trip Planning Guide.

As an aside, I really appreciated the following:

"Write up a trip plan to leave with a friend or relative in case you are overdue.
  • When to contact authorities if you are overdue.
  • Who to call, including phone number.
  • Where you parked your car.
  • What your route plan was, including escape routes if any.
  • What gear you are carrying."
Check out my detailed Trip Plan.