Map, Compass & GPS

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

Thursday, October 30, 2014

The Best Compass

Frequently people will ask what is the best compass a hiker can buy?  It really does make a difference.

My answer is that first I'll eliminate all the small ball and wrist watch compasses.  Those models just cannot provide accurate azimuth/bearing information.  They will provide a trend of direction but that is about it.

I'll then eliminate the inexpensive base plate models that can't be adjusted for declination.  The small Silva models come to mind here.  Some maybe suitable as a backup compass. 

I find that the Silva "Ranger" style is my pick.  It is accurate and keeps my navigation simple.  Importantly, this model can be adjusted mechanically for declination, has a decent sighting system and is simple to use.  Prices for this model will range from about $38 - $50.  Suunto makes a similar model too that is just fine.

Unique to this style of compass is the sighting system.  It's similar to sighting a hunting rifle. The compass box offers two methods (the notch on top and one at the hinge.)  Read the manual about using the mirror's line that is scribed/etched into the surface.

Adjusting for declination keeps things simple.  Just preset the declination value with the set screw (provided) for the area the hiker will be operating in.  This eliminates the need to remember the rhymes associated with declination (East is least &west is best.)

For tips on sighting with a compass go to my blog post.

Wednesday, October 29, 2014

The Basics of a Topographic Map


Reviewing a topographic map is usually the starting point for the planning of any back country trip.  A topographic map is your road map to the outdoors.  It provides you information at a scale that is meaningful and detailed.  

For years, the US Geologic Survey (USGS) has been the principal publisher of accurate maps.  Within the last decade we have seen many innovations in mapping products that include new mapping companies and publishers, software, maps for the GPS, and “Apps” for the smart phone.

Still, the USGS map remains the standard for back country navigation (visit the USGS’s site at www.topomaps.usgs.gov.)   I’d also recommend looking at June Fleming’s “Staying Found” or Bjorn Kjellstrom’s “Be Expert With Map & Compass.”  Once you develop a map foundation you will easily shift to many of the other products on the market today. 

Many publications, videos, and web sites will give you a complete rundown on the features, symbols and components to a map.  The key features that you should be aware of are:

·         Contour Lines These are the thin brown lines that snake across the map.  Contour
lines connect equal points of elevation such that every point on a specific line will be at that elevation above sea level.  Visually, the contour lines give you a mental three dimensional view of the terrain.  These lines provide shape and a sense of texture.  Contour lines provide a view of slope and pitch, depressions, ridge lines and level ground; the highs and lows of the earth’s surface.  There are two primary types of lines, index and intermediate lines.  Index lines stand out as they are a touch wider, a darker shade of brown and indicate the elevation with numbers such as 4500; the elevation is in feet.  Between the index lines are the thin intermediate line that are spaced uniformly and further define the elevation, slope and contour.  The distance intervals between the intermediate lines are specified at the bottom of the map adjacent to the scale data.

·         Scale Consider scale as your view of the map; it is like your “overhead zoom” setting.  To cut to the chase, a 7.5 minute map or quadrangle has a scale that is referred to as 1:24,000; where one inch is equal to 2000 feet.  It is your best source of information of the back country.  At this scale, the map has much more validity and provides more usable information for your backcountry planning.  You can view important landmarks, streams and geographic features.  To complete the navigation picture I always refer a second map, such as a map of the national forest (e.g., the Deschutes National Forest.)  Commonly, such a map will be “zoomed” way out and have a scale of 1:100,000 or 1:250,000.  Imagine that such a map would be made up of many 7.5 minute quadrangles.

·         North  Features on a map such as trails, roads, mountain peaks and streams are all laid out in relation to true North; the North Pole.  The north-south borders of the map and the small declination diagram are your best references for true North.  Other grid lines (such as the red Township, Section and Range lines) may not be aligned to true north at all.  Be careful of these lines should you need to triangulate your position on a map.

·         Declination This is the angular difference between true North and Magnetic North.  The red needle on your magnetic compass points to Magnetic North.  The accuracy of the information found in the Declination Diagram is dependent on the age of the map.  To get the latest declination for any area visit www.magnetic-declination.com.

Personally I use a magnetic compass that I can adjust for declination; it just makes my navigation easier.  When adjusted, my compass provides bearing information in degrees true as does my map and my adjusted GPS.

·         Coordinates Latitude and Longitude (Lat/Long) are the familiar coordinate system to most outdoorsmen and women.  Coordinate data is found at the top and bottom corners of each map.  Lat/Long coordinate increments are also found every 2’ (minutes) and 30” (seconds) on the sides of the Map.  A scaling device is necessary to pull complete coordinates off a map; this is a pain.

In the 1940’s a coordinate system know as Universal Transverse Mercator (UTM) was developed.  To keep a very long story short, your 7.5 minute map has a new grid laid over it, the grid dimensions are 1000 meters by 1000 meters.  For more complete information on UTM grid visit the USGS’s web site UTM or Letham’s “GPS Made Easy” (which is probably at your local library.)

Simplicity is the essence of UTM.  Scouts, hunters and hikers have joined Search and Rescue (SAR) teams around the country in using this system. 

Your GPS receiver can easily be switched to UTM from the set-up menu.

·         Bar Scales   Notice the bar scales at the bottom of the 7.5 minute map.  The scales provide measuring data in miles, feet and meters.   On the far left side of the meter scale, the scale is broken down into units of 100 meters, this applies directly to UTM.

Notice on the scale bar (feet) that 1 inch equals 2000 feet.

·         Map Datum Information about map datum is found in the lower left corner of a 7.5 minute map.  I have found that the simplest definition from GPS maker Garmin is:

“A math model which depicts a part of the surface of the earth. Latitude and longitude lines on a paper map are referenced to a specific map datum. The map datum selected on a GPS receiver needs to match the datum listed on the corresponding paper map in order for position readings to match.”

The bottom line: most 7.5 minute maps are made to the North American datum of 1927 (NAD27 or NAD27 CONUS on your GPS).  New GPS receivers are set to datum WGS84.  The difference between the datum could be over 100 meters/yards.  The solution: When pulling points off a map shift your GPS’s datum to match the map. 

If precision is not an issue for your outing don’t worry about datum.

Visit www.worldofteaching.com/powerpoints/geography/Mapping.pptThis power point presentation offers a fine overview of topographic mapping.  It’s free.




Tuesday, October 28, 2014

GPS Setup - Map Datum

Map Datum is a critical GPS setting.

In my land navigation classes I emphasize that hiking groups should all be on the “same page” regarding the set-up options of their GPS receivers. There are several essential steps that ensure accurate position reporting, rendezvousing and returning to camp safely.

While planning a journey or at the trail head, taking the time to adjust settings among hiking partners is critical.  Before departing, validating map datum and coordinate format should be a priority.

First, match the map’s datum.  A topographic map identifies datum in the map key.  Once the datum is identified ensure that all GPS receivers are set to match the correct datum.  See the illustration below.

Map datum is a mathematical model of the Earth used by map makers.  Datum allows for the accurate transfer of geographic data from a spherical earth to a flat map.  In the United States, there are three common map datum’s found on topographic maps.  These are WGS 84, North American Datum 1927 (NAD27) and NAD83.  Select the datum that is used on the map.  Receivers are set at the factory to WGS 84.

To change the datum go to the receiver's main menu and select "set up" from there go to "position format."


 








Monday, October 27, 2014

Communications In An Emergency

Is there a national level way to communicate with friends and family in an emergency?  

The answer is yes.

We often think of the American Red Cross (ARC) as a group of volunteers that coordinates blood drives, hands out blankets and provides meals during an emergency.

But there is a lot more!


Take a look at ARC's web site at www.redcross.org.  At this site you can donate, get signed up for first aid training, shop and learn how to give blood.

There is another ARC site you should check out and that is

https://safeandwell.communityos.org/cms/index.php

From this site, family and friends can (quoted from the site);

  • "After a disaster, letting your family and friends know that you are safe and well can bring your loved ones great peace of mind. This website is designed to help make that communication easier. 
  • Register Yourself as “Safe and Well”
    Click on the “List Myself as Safe and Well” button to register yourself on the site
  • Search for Loved Ones
    Concerned family and friends can search the list of those who have registered themselves as “safe and well” by clicking on the “Search Registrants” button. The results of a successful search will display a loved one’s first name, last name and a brief message."
Do communicate this information to your families in advance.

Thursday, October 23, 2014

Sources of Reference for the Backcountry Hiker

There is a lot of reference material published and online that the backcountry traveler has access to.
Outdoor Quest image

There are some that are no longer valid or are just plain inaccurate.  For example, one major magazine publication had an article a few years ago about hiking on one of the major trail systems in  the United States.  When it came down to how to lighten a pack  the comment was made to leave the map, compass and GPS at home because the trails were so well marked.  As a Search and Rescue team member that statement leaves me cold.  During a recent SAR convention in Oregon I brought that up and found no one in agreement with the magazine.

Thus I always read with caution if I don't know the writer.

My recommended short list of good solid references includes the following:

  • Peter Kumerfeldt's book Surviving a Wilderness Emergency
Some books I tend to steer clear of.  For example, Bradford Angier wrote a series of books about living off the land.  The books are dated and many of is suggestions are out of date.

Do visit Kummerfeldt's website at www.outdoorsafe.com  and check out his extensive bibliography of published material.


Sunday, October 19, 2014

New Web Site

I left my old web host and have migrated from a 10 year old micro soft office product to Word Press.

Please take a look a www.outdoorquest.biz and let me know what you think.  Please post your comments on this blog.

Thank you

Friday, October 17, 2014

Backcountry Travel Off The Beaten Path

I just finished teaching a land navigation class at the local community college.  I had lots of questions about hiking off the beaten path; bushwacking through the backcountry. 

I paused my presentation to capture the moment by engaging the students in what their key considerations and thoughts were.  Here is a round up of some of what we talked about and some of the recommendations made by the group:

  • Off trail hiking preparation starts at home.  This is the time to review maps of the area paying particular attention to terrain, landmarks, water ways and potential hazards along the way.  Even though the hiker might be bushwacking trail guide books might have some good info of the area.

  • Maps are prepared and stored in a zip lock bag or map case.

  • The hiking party needs to ensure that their navigation equipment is all set up  such that every one is on the same page.  Compasses should be adjusted for declination, GPS receiver set-up options (coordinate system, map datum, north reference) should all match.

  • I like to consider that hiking has the apects of a team effort.  We work and stay together during the hike.  This isn't the time to hike alone.

  • When going off trail save the point of departure as a waypoint on the GPS receiver and give the waypoint a name.  Mark that position on the map too.  Mark a waypoint at key crossings abd course changes.  Those new to GPS should mark frequently to develo the muscle memory. 

  • Topo maps provide a general description of the area through the use of colors, symbols and contour lines.  I like to evaluate and orient my map during breaks and keep my position data current.  Terrain association plays a big part.    Maps could be updated with position data during breaks, stops for lunch or when ever it just makes sense.