We all know that the Earth is not flat
nor is the Earth round. Those two facts make the map-makers job
difficult. The Earth is however more round than flat and we all
know that smart people long ago figured out various ways to peel
the skin of the Earth to make flat maps, each with it's own distinctive
distortion. Fortunately for backpackers the mapping distortion
from specific map projections don't matter much (at least in the
lower 48 states.)
The problem of concern, is how backpackers can
get from where they are now to where they desire to be. Let us
call that backcountry navigation. Basically backpackers need to
know where they are now relative to their map and how to use the
map and compass to guide them to where they want to get to. GPS
can make part of the job easier but it is suggested that one should
first learn to use compass and map. The compass and map do not
require batteries and are not fragile, at least compared to the
GPS. It is wise never to rely on a GPS operating when you get
into a survival situation, therefore backcountry navigation skills
with a compass and map are essential.
The compass is the most basic tool. Even if
your don't have a map or don't know where you are, the compass
can help keep you from walking in circles and can keep you aimed
towards your chosen direction. There are many excellent compasses
available for backcountry navigation. To learn about considerations
in using compasses and features in different compasses, go
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
and cover every part of the entire United States. You can learn
more about acquiring and using the topo maps (pronounced "toe-Poe"),
as well as the exciting new capability of getting them on your
computer, and printing your own specialized topo maps, go
The GPS is a navigational tool produced by the
U.S. military but now available to all civilians. 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 it 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. To learn more about backpacker GPS's, their
use and special cautions that you need to know, go
Back to Top
We all know a compass has a needle that points
to the North. What else do we need to know about compasses to
allow us to buy and use them in the backcountry? Here are some
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
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.
- 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.
- There are some simple additions to the compass that are extremely
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
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.
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
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
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
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
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
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
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
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
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.
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.