• Compasses
  
• Maps
• Computer Maps
• UTM Grids
  
• GPS

1. The compass points to a different "North" than the True North that Maps are drawn to. Maps are drawn to the True North which is the North that comes from the "top" of the globe and is used for making up grid lines such as longitude lines.
   
   The compass however points to a place on the earth that magnetic force lines appear to emanate from. This point in Northern Canada is usually shown on the map of Canada if you are interested. The difference at any location on the Earth between the True North and the place the compass needle points is called declination, measured in degrees. It also can be an error to the East or West of true North, so declination is given in degrees East or West.
   
   Some compasses have a scale that makes it easy to compensate for declination and the mirrored compass below shows such a scale. The declination at the Wyoming trail shown on the home page is about 16 degrees East declination. That means a compass used on that trail is pointing 16 degrees to the East of true North lines that are drawn on a map.
   
   A backpacker on this Wyoming trail who wants the compass to point to the True North of the map, must mentally think of the needle as being 16 degrees more to the West to make up for the 16 degree Eastern error in that region. One can also make use of compasses that allow for correction of declination, by following directions that come with those compasses.
   
   
2. Compasses are made to work at specific areas of the world. If you buy one here, it may not work properly in the exotic area you just spent all that money to fly to. Just buy one locally or contact a compass manufacturer to get the proper one before you leave.
   
   
3. There are some simple additions to the compass that are extremely valuable.
   
   The basic "orienteering" compass (shown below) has a base with a fixed arrow pointing in the direction to walk, and a rotatable round ring to set the compass. You determine which direction you want to proceed in (your bearing) by looking at your map and reading off the degrees, between 1 and 360 (directions to do this come with each compass).

 

To set the compass to that bearing the ring is rotated until the degree number is under the mark by the fixed arrow (on the top of the picture). It is set at 110 degrees on both compasses shown.

Then holding the compass approximately level so the needle turns easily, you rotate your body around until the red moving North needle is pointing to the N on the ring. At this point you will walk along a 110 degree bearing by following the arrow on the top.

Of course as you move you have to keep adjusting your body to keep the red needle pointing at the N. You soon learn that you can walk in the general direction, and then just check the compass from time to time. Each time you recheck the compass you put the direction to walk arrow at the end so it is directly in front of you and rotate your body to get the red arrow to point at the N on the ring.

Some compasses have, in addition, a fixed scale that makes it easy to adjust for declination. One can find the local declination from the information on the map border. Then one can easily use the fixed scale to see how far from where the needle is pointing the truth north of the map points.

Some compasses also add an adjustable mirror (shown on the left above) that helps in sighting on a remote object and reading the direction. In addition the mirror is useful to see how dirty your face has gotten and how much your hair needs to be combed.

It is recommended that if one is starting out that one gets a compass book, either at the library or at a local backpacking store, and learns what they teach by getting a basic "orienteering" compass and practicing at home or in a park. If you wish you may purchase a topo map of your home area as described under MAPS in the next section.

Back to Top

MAPS

We will discuss below, what is probably the most popular map, topo 7.5 minute maps, and suggest how to get the maps that cover your area of interest. We will also discuss a new product that provides topo maps on CD that can be manipulated in your computer and printed out on your printer, or sent to Kinko's, etc. for larger printouts. Go to Computer Maps. Finally we will discuss why UTM grids may be easier for you to use when carrying a GPS unit, than the more traditional latitude and longitude lines, and how UTM grids get drawn on your map. Go to UTM Grids. Also please check your library and your local backpacking store for further information on compass and maps.

Finding the TOP0 7.5 MINUTE MAPS

The map is essential for all trips, even when you are "just" following a trail. The use of the map and compass together is the navigational skill every backpacker should constantly work at. There are excellent maps available today for the backpacker but 7.5 minute topographic maps are probably the most popular. They are for sale by the U.S. Geological Survey (USGS) and cover every part of the entire United States. However getting the maps for your hike or area of interest isn't always easy, but here are some helpful hints.

You can obtain the maps you want from: 1) your local backpacking store; 2) resellers; 3) the USGS; or 4) you may buy a set of CD's and print your own. Each method has its advantages and disadvantages.

Getting the maps from your local backpacking store is by far the easiest. The disadvantage is that they usually carry only local maps and sometimes run out. If they are out of stock you will at least know the name of the maps you need and can easily order them from the USGS. However if you live in Michigan and want to hike in Wyoming your local store probably can't help you. Then you must find another means to determine the name of the maps you need so that you may order them.

You may have local resellers of maps that you can find by checking the "Yellow-Pages" under maps. They may be able to help you find maps from other areas. There may also be on-line resellers which you can find by searching the internet. If you are going to hike in a National Park you can contact the park's bookstore which will have not only topo maps but often have excellent maps covering specific trails.

However the most straight-forward way is to purchase topo maps from the USGS at www.usgs.gov. Before you go to the USGS site you need to have a road map of the state of interest or a road atlas of all the states. Familiarize yourself with the nearest towns and the major roads leading near the trail head especially U.S. Numbered Highways. Then go to www.usgs.gov and begin moving down the home page until you find "Explore our Products and Data". Go down this list and click on "Mapfinder".

Under Mapfinder click on "Enter the Name of a Populated Place". Enter the name of a nearby town with a U.S. highway going through. You will see a map with some cities on it in red, some roads in purple and rivers and lakes in blue. You will also see rectangles with names in them. Each rectangle is a topo map. Your job is to figure out which one holds your trail head, based on the sparse map information of a few roads and rivers and lakes. Once you guess at your first map you may order those around it that you guess hold all the areas of interest to you. The USGS site lets you place an order for your maps using a Shopping Cart. The USGS site also lists dealers around the country however you may find that many of them provide help with only maps local to them. Good Luck.

Back to Top

COMPUTER MAPS

In this hi-tech world we now have the advantage of purchasing topo maps on CD's, to be able to manipulate them seamlessly on our computers and to print them out the way we want them. The advantages are many however you must pay the cost of about $50 for an area of a state or about $100 for all topo's of the entire state. Most states are available, but sub-areas seem limited to very popular places. Do a computer search of "topographic map software" to find the different offerings and to get a feel of the tools and manipulations available. Our favorite is TOPO! now owned by National Geographic at www.topo.com.

Right now computer maps can be considered a supplemental tool to USGS paper maps. The computer maps let you completely explore an area before you go and allow you to prepare your trip better by knowing the exact position of trailheads, by getting ideas of cross trails and connective routes and by obtaining elevations and exact locations of any point of interest. Also most show you the name of the 7.5 minute topo map at any point you wish. They also let you choose as small or as large an area you wish to print out, independent of where the topo map boundaries are. However printing out maps is probably the weakest link since most people are limited to 8.5" by 11" or 8.5" by 14" printers.

For the current state of things it appears the best use of computer maps is the making of detailed maps of areas one plans to spend more time at, adding in additional information wanted on the map, printing maps on both sides of the paper, etc. It is likely that the computer generated maps may be mixed with purchased topo maps, which cost $4-$6 each, depending on the source. The cost of the maps printed from the computer is probably greater than the cost of the topo's, for the same areas, However having unique maps of certain areas and the ability to pre-explore a much larger area is worth the cost to many.

A word about printing your maps. Most people's printers can print on legal paper which is 8 1/2 x 11" but which is a little small for maps. A size of 11" by 17" can be printed by some of the newer printers and possibly 13" by 19" for some of the higher end printers. But depending on the number of maps you want to print it may be cheaper to pay Kinko's to print them if you live near a metropolitan area that has a Kinko's. Kinko's prints a nice color 11' by 17" for under $3. To use Kinko's you can download their printer program which adds itself to your selection of printers and makes your output file compatible with their printers. Go to www.kinkos.com. (The map files are large and a Zip disk is probably the easiest way to transfer your files for printing, although Kinko's does offer an on-line method).

Kinko's also prints larger sizes than 11" by 17" for $12.50 per square foot which is considerably more expensive. At $12.50 per square foot, a 13" x 19" map costs $21.44 and a 19" x 24", the size of a topo map, would cost $33.33. Printing at 11" x 17" makes useful maps and seems to be a reasonable compromise.

To conclude here are some cautions to be aware of when using these computer maps. First the maps apparently were scanned in from the latest version of each paper map. Sometimes there are small discontinuities at boundaries but nothing to be very concerned about. What may be disconcerting is that one topo map may show elevation marks in feet and the next one in meters. Since the maps on the computer are seamless, you don't know where the borders of the original maps are and may suddenly find yourself interpreting meter height as height in feet or vise versa.

But even this is not disastrous because every place you put the cursor it reads out the location coordinates and elevation in the units that you choose, on the corner of your screen. Therefore if you have chosen feet for your readout, the computer will read out feet in the lower corner of the screen even though the cursor is on a point on that map that was printed in meters. Don't let these little problems deter you because computer maps can be extremely useful and a great contribution to your enjoyment of the back country.

Back to Top

UTM GRIDS

Grids are the vertical and horizontal lines superimposed on the globe to allow any place in the world to be able to be located by two numbers designating the two lines that intersect at the place of interest. Almost universally, latitude and longitude lines have been used to provide this service, and they appear on most flat maps as well as globes. However other schemes have also been developed and are easier to use than latitude and longitude for certain cases. UTM, you don't even need to know what it stands for, is one such useful grid scheme. Everyone just calls it "UTM".

When you look at a topo map you will see latitude and longitude readings on the corners of the map by a black tic mark.. In between the corners you will see typically two latitude readings along the sides and two longitude readings along the top. There is a large space in between the marks and the marks have difference distances on different maps. However if you look closely you will find little blue tic marks on the sides and tops of the map. These are UTM tic marks and they are much closer together than the latitude and longitude lines and they are evenly spaced on different maps. This makes the UTM system easier to use when trying to figure where you are between the tic marks when the GPS gives you a reading. The GPS will provide either latitude and longitude or UTM coordinates as you choose.

To aid in using the UTM tic marks in the field, it is easy while at home, to draw the lines by pencil between the corresponding tic marks on each side, and between top and bottom. One ends up with little boxes slightly larger than 1-1/2 inches on a side, which is sufficiently small enough to easily determine your location within the box, based on the UTM information given by the GPS . The GPS provides the information to quickly determine which box you are in and how far over an up in the box you are. Trying to do this using latitude and longitude on a topo map is much more difficult, therefore the recommended use of UTM coordinates.

It is possible to make latitude and longitude just as easy to use with a GPS, if you use computer generated maps. The computer generated maps allow you to choose what the spacing between latitude and longitude lines are and can provide you boxes about the size of the UTM boxes. (The computer also draws either the Lat-Long lines or the UTM lines for you if you ask it). However most hikers prefer UTM because it is still easier to find the box quickly and most backpackers also need to use some paper USGS topo maps where UTM is the only way to go.

Remember the only way to stay found is to practice and practice with the compass and map after which you may augment it with compass, map and GPS. Use the GPS when it works, but in a distress situation the batteries will eventually run out and one must always be ready to rely on basic navigation skills.

Back to Top

GPS

Introduction

The Global Positioning System (GPS) is a multi-satellite system to aid navigation. It was originally developed by the Military but its mission has been expanded to serve civilian needs. Large numbers of both military and civilian users have produced a market that has brought the price of a civilian GPS terminal to between $100 and $300, a real bargain for what you are getting. Backpackers generally refer to their GPS terminal as just a "GPS".

The backpacker's GPS is a pocket sized box that acquires radio signals from a constellation of satellites and reads out the backpacker's current location anywhere in the world that the GPS is taken. This high-tech satellite driven system, has an antenna, multiple radio receivers, a computer and an LCD display in a pocket size box, powered with 2 AA batteries, and costs as low as $100. History may determine that the GPS system is the greatest payoff to the taxpayer in the first 50 years of the space program.

What can a backpacker do with a GPS? Try these: 1) Drive to the trail-head of an unfamiliar trail quickly; 2) Find the exact spot on a trail to start bush-whacking to find some off-trail thing of interest noted on the map; 3) Without disturbing your surroundings, mark a good off-trail campsite you found so you can get back to it exactly, each time; 4) Determine which of a group of alternate trail intersections is the one you saw on the map; 5) Map out a new trail and draw it on a map; 6) Rendezvous with another hiker at an agreed-to spot, knowing you are both heading for exactly the same spot even though neither of you had been there before.

Many of the tasks mentioned above can be accomplished without a GPS by using orienteering skills. Everyone should learn orienteering skills for basic survival purposes. Silva, a compass maker, produced an orienteering manual, cira 1985, from which the following definition is given: "Orienteering is finding your way with map and compass along a stretch of unknown ground to your pre-selected destination".

If you purchase a GPS, you soon find that these orienteering jobs are made so easy, one quickly begins to rely on the GPS. Therefore a certain amount of discipline is needed to keep honing your orienteering skills, while still using the GPS for convenience. With proper discipline a GPS can speed up your development of orienteering skills by reducing feedback time.

With your GPS turned off, try to get from here to a pre-selected destination along a stretch of unknown ground. If you get to a point where your are ready to give up, turn on the GPS and see where you really are. Try this all the time you hike, using the GPS only as a last resort. Your life is worth it. (Orienteering books are available in your library and in backpacking stores, get some).

Preparing to Use the GPS

The GPS satellite system is complicated but fortunately you don't need to know much about it to use it well. There are enough satellites in special orbits around the earth to provide GPS coverage anywhere in the world. This results in the condition that your GPS will be able to pick-up enough of the satellites at any time to give you your location anywhere you are in the world. Here is some information about using a GPS.

If you have a new GPS there are a few things you need to do to it before you use it in the field. One of these is called RTFMS by the computer people, which means READ THE FAMOUS MANUAL SIR, or something like that. (Of course you read the manual thoroughly and fully understood it before you turned the GPS on so you probably don't need to read any of the following, but give it a try anyway.) The first order of business that the manual will tell you about is loading the batteries.

Follow the instructions, especially checking the instructions on the case which are the ones you will use in the field. After you load the batteries turn on the power and see the LCD screen begin to display characters. If nothing happens on the screen after a little bit, hold the on-off switch on for a while, since many models require it to be pressed longer than an accidental press would last. If it still doesn't come on check that the batteries are loaded right. Some GPS models have very confusing battery loading instructions on the case, so examine carefully.

The second order of business is to understand the menu and button system on the front of the GPS and how you get back and forth between the different groups of information that show up on the LCD screen. Buttons are expensive to put in a device like this therefore there are only a few buttons. This requires you to understand how this particular GPS lets you get from one screen of information to another, because the whole use of the GPS is for it to get you the information you want onto the GPS screen.

There is usually a menu button or some similar function that brings up a list on the screen, of the basic screens that the GPS can bring up for you. One of these is "setup" or something similar that you need to use before you start to use GPS for navigation.

There are generally two types of functions under setup. : One is "initialize" or a similar term and the others are various choices you make to personalize the readout like choosing 24 hour time display vs AM and PM, choosing to display in feet or meters,. picking a coordinate system and choosing speed units, etc.

Initialize lets you tell the GPS where in the world it is. That's no joke. If you don't first tell the GPS about where it is, it will figure it out on its own, but it is likely to take so long you will give up on it. So be nice and use the initialize menu to give it a jump start.

For instance your GPS may let you pick the country that your are in, and if you pick USA it will let you pick the state. The GPS can rapidly acquire from there and quickly give you an accurate location of exactly where you are. When you turn it on again it is already initialized so you don't have to repeat this setup. If however you fly somewhere on a backpacking vacation, when you get off the plane and turn on the GPS it is appropriate to re-initialize it.

After initialization, finish set up by going through and picking the various choices like feet vs meters. When you get to "coordinate system" pick UTM, you won't be sorry. (Of course you need to practice using the UTM readouts with your map before you hit the trail).

One choice you may not know how to make is called "Map Datum" or something similar. It will have a list of things like "WGS84", "NAD27", etc. These refer to various models of the solid earth. You pick the one that your map used. You can find the datum your topo map used, by looking in the lower left hand corner of the map. Somewhere in the information there it may say something like "1927 North American Datum" which means you pick NAD27. (Get this right. Putting the wrong datum in can give you a constant error of as much as a city block). After picking the datum (and you need to switch datum if you switch to a new map with a different datum) then finish picking your remaining choices and you are ready to use your GPS.

Back to Top

Using Your GPS

Somewhere in your manual it should tell you how to hold the GPS so the antenna best picks up the radio signals while you are walking along, and also if you set it down. Some models you hold flat in front of you as if you were pointing ahead with the GPS. Be sure to find out how yours should be held.

The first screen that the GPS will display when it turns-on depends on the model, but many begin with a basic screen that shows the GPS status and a location reading, a time and date, and the datum being used. The status of the GPS is whether it has locked onto enough satellites to give you a new location. It takes a while after turn on before it gets to this condition and it will provide some indication that it is unlocked and may also say something like "searching". Before it has locked up it will likely still display a location reading, but it will be the last one it got when it was locked, so be careful to always check the screen to see that it is locked before you use a location.

As soon as the GPS indicates lock it will give you a new location. If you notice your GPS going in an out of lock while you are watching it, the location it produces may not be too accurate. Two reasons for not being able to stay in lock are: 1) You are in a forest under heavy canopy which is somewhat wet; or 2) you are in a deep canyon or ravine where the view of the sky is very restricted. In the case of the forest canopy the safest thing to do is wait until you can get to a clearing or out on an exposed area. In the case of the deep canyon or ravine just wait to see if it stabilizes after a while. In either case if your are stationary and the various locations provided are pretty much the same after each re-lock, they are probably safe to use.

Many GPS's can display in 2D and 3D or some similar notation. 2D means only enough information from the satellites have been obtained to calculate your coordinates, lat/long or UTM, but not enough to calculate your elevation (distance above sea-level). When the GPS has enough information to provide elevation as well it is called a 3D location. (It may be debatable but the location accuracy is generally much better than the elevation accuracy.)

The GPS will provide your position as either a latitude and longitude or as UTM coordinates, your choice (our choice is UTM). You then open up your map and find the corresponding lat/long or UTM coordinates on the map and that is where you are.

Of course your map only has a few lat/longs marked and a few UTM's marked, although there are many more UTM/s marked than lat/longs on a topo map. That is one of the reasons that it is recommended that you set the GPS to use UTM coordinates. If you draw the UTM lines between the tic marks on either side and between top and bottom of the map you will have drawn small boxes evenly across the map. The GPS tells you which box you are in and how far you are between sides and how far you are between bottom and top of the box. The UTM boxes locating your actual position are much easier to use than trying this with lat/long line constructed boxes.

Besides being able to determine where you are on a map the GPS has other functions. Two major ones are: 1) being able to store locations and name them, often called way-points; and 2) to have the GPS guide you to a particular location. Way points are helpful to follow your trail back the way you came, or to even take a short cut to get back, to provide information to others about locations that you have found and to draw a route or trail onto a map. Using the GPS to guide you to a location that you desire to get to is certainly a useful tool for all backpackers. The location-to-get-to is stored as a way-point either by reading off a map and manually entering it into the GPS (either before or during the trip) or by letting the GPS store it as you pass the point. All of these functions and more can be learned by following the manual instructions.

Which GPS should one get? Some obvious things to check are how long the batteries last with the GPS on and displaying on the screen, how heavy it is with batteries in place and operating (many use only 2 AA batteries), how well you can see and use the LCD screen, how rugged it seems to be, how easy it is to fit in your pocket or pack.

Some extras that one can get in a GPS are: External plug in antenna for use in the car (a normal GPS works sitting on your dash board but an external antenna may work better); and a connector used to transfer data to other equipment (such as your map program on your computer).

Things like the number of way-points the GPS can store are not too important to many but may be to some. Built-in maps is not a useful feature to us because the screen is too small to make use of them and their details are not generally useful, but check it out if this seems of interest to you.

The ease of entering alpha-numeric names to the way-points and ease in editing the way-points is important but may add to the cost. Take a look at the manual, the clearer it is written and the more comprehensive it is the easier you will learn to use it but that may also add to the cost.

The cost may go up slightly for the above mentioned items, but it can go up significantly for high performance such as: 1) being the lightest, smallest, longest lasting on a set of batteries; 2) having sensitivity to operate well in less than ideal radio conditions; 3) ability to most rapidly acquire the satellite information and develop a location both when it has a reasonable initialization and when it is has not been initialized; and other performance resulting from superior technical design.

There is no advice in that regard given here. The best advice can come from someone who owns a model, has tested it well and is willing to show or tell you about its performance. Comparing this information between models of various costs will really help, just as you might do in buying an automobile. An alternative it to find a cheap GPS, buy it, learn about the subject and test it enough to be an informed buyer when you are ready to get one that will really meet your needs. Good luck in this adventure.