How to: Navigation
How to: Navigation
“Be sure you are right, and then go ahead,”
-Daniel Boone, one of the greatest of American wilderness travelers knew this as all wilderness travelers must and phrased it in an epigram that has become classic.
Navigation is one of the most basic elements of life. Without the skill of navigation we would literally be stuck in one place, never able to make it from one place to the other. Many people never really think about this skill, which is an awful shame. Obviously you are not one of those people, because you are reading this now. Navigation can be as simple as being orientated with your sorroundings, or as complex as a satellite network that is backing up a hand held GPS device that does all the work for you. In the article that follows you will learn the basics of navigation, which I feel is the only way to go. If you are lost in the woods, you most likely will not have a compass or a map, or even a GPS, so it’s best to know how to make your own compass. The best knowledge that you can gain from this is that being prepared is the only way to go. If you are going into the wilderness it’s best to bring a map and compass, but if you can’t at least take the time to know where you are, what land marks to keep an eye out for and where the nearest help will be if you get into trouble.
USING MAP AND COMPASS
Since the compass needle points to the magnetic pole, you must compensate for the difference between the positions of the true North Pole and the magnetic north. This difference is called declination and it varies from nearly zero degrees to twenty-five degrees east or west depending on what part of the continent the reading is being taken from. The near zero degrees applies if the reading is taken when the magnetic north and the true north are in line. However, the only time declination is of concern is when you are trying to follow a map that has both magnetic-variance lines and grid lines based on the true north. Declination needs to be known for navigation. Both Geodetic Survey and U.S. Coast Gaurd maps show magnetic variance as dotted lines and grid lines as solid lines. Declination is always given in degrees east and west. But more about this later. The elementary way of using a compass is as a direction finder. No one should venture into a wilderness area without a map, a good compass, and a knowledge of how to use both. To do this, you must simply wait until the needle stops, turn the dial until the north arrow and the needle are aligned, and then use whatever bearing will bring you to your destination. In such elementary compassing, declination is ignored. However, this technique works well only when short distances are involved or when the objective is large such as a road or a river and you don’t care where you hit it. A variation of this technique can also be used to reach an objective that is visible only at times. In this case you simply take a compass heading and use it whenever you lose sight of the objective. However, for more sophisticated compassing such as hitting a bay on a small lake many miles away, a map is needed on which the location of the camp is pinpointed. The technique here depends on the type of compass.
Determining a course with a simple compass:
1. Draw a line from your starting point to the objective.
2. If the map has no north-south line running across your intended line of travel, then draw one by joining two points of the same longitude.
3. Place a protractor along the north-south line with the center point at the junction of your path of travel and the north-south line.
4. Read the bearing of the path of travel in degrees at the outer margin of the protractor. Let us say that it is eighty degrees.
5. Now you must convert the map’s true north bearing to a magnetic north bearing by applying the declination shown on the map. Let us assume that the declination is ten degrees E. Then the bearing you have to follow to reach your objective is seventy degrees E the declination (ten degrees E) minus the reading of your path of travel as shown by the protractor (eighty degrees).
Determining a course with a Sylva or other good quality compass:
1. Place your map on a flat, level surface. If you wish, you can draw a line from the objective to the starting point, but this is not necessary.
2. Align the transparent plate of your compass along the path of travel so that the line of sight is pointing in that direction.
3. Turn the compass until the lines on the housing are parallel to the north-south lines on the map. If the map does not have north-south lines, you will have to draw one crossing your path of travel. The north arrow on the housing will now be pointing to true north.
4. Turn the compass housing the number of degrees of declination marked on the map. (If the declination is east, this means a clockwise turn; if the declination is west, an anti-clockwise turn.) The index pointer now reads the magnetic bearing of the path of travel.
5. To travel the line of direction required, turn the whole compass without moving the housing so that the north end of the needle points over the north end of the engraved arrow. The course to travel will be the line of sight or the direction of the sides of the transparent plate. Occasionally someone gets lost in spite of having a compass and knowing how to use it, usually because the traveler lacked confidence in the compass. He “knew” that the compass was wrong and that his sense of direction was right. Compasses seldom lie. They may be affected by something outside the magnetic influence, but that’s up to the compassman to discover ahead of time. The compassman may also make mistakes. If he reads the headings incorrectly, he cannot blame the compass for getting him lost. Learning how to use a compass can be great fun. The way to start is in territory that you know. If you can follow bearings with good accuracy in familiar country, you are ready for the wilderness.
No one should go into an unfamiliar wilderness area without a good map. For canoe tripping, a map with a scale of two miles to one inch is fine. For hiking, a map with a larger scale is better, preferably one with contour lines. Familiarize yourself with the map first. Look at the topographical features that you will encounter along your route or path of travel. Learn the legend. To protect your map from moisture, cover it with clear, selfadhesive plastic sheeting or spray it with a clear plastic spray. There are also plastic map cases available which allow the map to be folded so that the sections that are in use are visible. These are a good idea on any trip.
WILDERNESS MAPS
Topographical maps can be a tremendous asset to any outdoorsman. A topo map is different from a road map because it shows the features of the land – the topography. Also, it shows the type of vegetation, old logging roads, foot trails, cabins, mining and lumber camps, power lines, streams, swamps, and springs. By studying a topo map, an outdoorsman can get a good picture of what an area looks like and what he can expect to find there. Of all the millions of words that have been written giving advice to outdoorsmen on virtually every form of outdoor recreation, surprisingly little has been said about the usefulness of topographical maps. I would no more dream of going on a wilderness trip of any sort – fishing, hunting, backpacking, canoeing, ski touring, or snow mobiling – without a topographical map of the area, than I would of going without an ax. The topographical map will not only show me landmarks, help me with navigation, and tell me what kind of terrain lies ahead, but it will give me an idea of the type of wildlife and fish habitats I might encounter. Marshes may hold waterfowl. Small, spring-fed mountain streams and ponds may have trout. The marshy lakes of northern Canada are ideal places to look for moose during summer and early fall because moose like to feed on aquatic vegetation. The list of possibilities is endless.
Even in settled farm country, topographical maps are of immense value. I have used them to locate tiny hidden trout streams, small marshes where other waterfowlers are seldom encountered, likely looking woodcock covers along streams, and moist swales, and high hardwood ridges with interesting snowshoeing and ski touring possibilities. By using the topo maps first and scouting the area, I am able to get away from the hordes of other outdoorsmen by finding little pockets of woodlands tucked away out of sight from roads. The key to using a topographical map lies in learning the symbols and codes. They tell the story of what actually lies on the ground. Generally the maps cover one quadrangle, one-quarter degree of latitude and longitude. The scale of the map can vary, but the larger the scale, the more detail the map shows and the more valuable it is. The most useful scale is a seven-and-ahalf-minute quadrangle series. On this scale, one inch on the map represents about two thousand feet on the ground.
NAVIGATION WITHOUT A COMPASS
Navigation without a compass is possible using several methods, but the biggest thing to remember is that the sunrise/moonrise is in the east and sunset/moonset is in the west.
First is the shadow-tip method, find a straight stick 3 feet long, and a level spot free of brush on which the stick will cast a definite shadow. This method is simple and accurate and consists of four steps:
• Step 1. Place the stick or branch into the ground at a level spot where it will cast a distinctive shadow. Mark the shadow’s tip with a stone, twig, or other means. This first shadow mark is always west-everywhere on earth.
• Step 2. Wait 10 to 15 minutes until the shadow tip moves a few centimeters. Mark the shadow tip’s new position in the same way as the first.
• Step 3. Draw a straight line through the two marks to obtain an approximate east-west line.
• Step 4. Stand with the first mark (west) to your left and the second mark to your right–you are now facing north. This fact is true everywhere on earth.
An alternate method is more accurate but requires more time. Set up your shadow stick and mark the first shadow in the morning. Use a piece of string to draw a clean arc through this mark and around the
stick. At midday, the shadow will shrink and disappear. In the afternoon, it will lengthen again and at the point where it touches the arc, make a second mark. Draw a line through the two marks to get an accurate east-west line (See figures below).
Using a wristwatch to determine general cardinal direction.
(a) Digital watches. Visualize a clock face on the watch.
(b) Northern Hemisphere. Point hour hand at the sun. South is halfway between the hour hand and 12 o’clock position.
(c) Southern Hemisphere. Point the 12 o’clock position on your watch at the sun. North is halfway between the 12 o’clock position and the hour hand.
POCKET NAVIGATOR
Gather the following necessary materials:
· Flat writing material (such as an MRE box).
· 1-2 inch shadow tip device (a twig, nail, or match).
· Pen or pencil.
Start construction at sunup; end construction at sundown. Do the following:
· Attach shadow tip device in center of paper.
· Secure navigator on flat surface (DO NOT move during set up period).
· Mark tip of shadow every 30 minutes annotating the time.
· Connect marks to form an arc.
· Indicate north with a drawn arrow.
Note: The shortest line between base of shadow tip device and curved line is a north-south line.
Do the following during travel:
· Hold navigator so the shadow aligns with mark of present time (drawn arrow now points to true north).
Remember the navigator is current for approximately 1 week.
USING THE MOON
Because the moon has no light of its own, we can only see it when it reflects the sun’s light. As it orbits the earth on its 28-day circuit, the shape of the reflected light varies according to its position. We say
there is a new moon or no moon when it is on the opposite side of the earth from the sun. Then, as it moves away from the earth’s shadow, it begins to reflect light from its right side and waxes to become a
full moon before waning, or losing shape, to appear as a sliver on the left side. You can use this information to identify direction. If the moon rises before the sun has set, the illuminated side will be the west. If the moon rises after midnight, the illuminated side will be the east. This obvious discovery provides us with a rough east-west reference during the night.
USING THE STARS
(1) North Star is used to locate true north-south line. (2) Southern Cross is used to locate true south-north line.
OTHER MEANS OF DETERMINING DIRECTION
The old saying about using moss on a tree to indicate north is not accurate because moss grows completely around some trees. Actually, growth is more lush on the side of the tree facing the south in
the Northern Hemisphere and vice versa in the Southern Hemisphere. If there are several felled trees around for comparison, look at the stumps. Growth is more vigorous on the side toward the equator and the tree growth rings will be more widely spaced. On the other hand, the tree growth rings will be closer together on the side toward the poles. Wind direction may be helpful in some instances where there are prevailing directions and you know what they are.
Recognizing the differences between vegetation and moisture patterns on north- and south-facing slopes can aid in determining direction. In the northern hemisphere, north-facing slopes receive less sun than south-facing slopes and are therefore cooler and damper. In the summer, north-facing slopes retain patches of snow. In the winter, the trees and open areas on south-facing slopes are the first to lose their snow, and ground snowpack is shallower.
ORIENTATING A MAP
Orient the map by unfolding the map and placing it on a firm, flat, level nonmetallic surface. Then align the compass on a true north-south line by rotating the map and compass until the stationary index line aligns with the magnetic variation indicated in marginal information. Easterly you will subtract variation from 360 degrees, and westerly you will add variation to 360 degrees. If there is NO compass, orient map using cardinal direction obtained by the stick and shadow method or the celestial aids (stars) method. To determine your specific location you can use one of two techniques, Triangulation (resection) with a compass is where you find 3 or more azimuths to locate your position. Positively identify a major land feature and determine a line of position (LOP). Check map orientation each time the compass is used. Plot the LOP using a thin stick, blade of grass or pencil line.
GLOBAL POSITIONING SYSTEM
Global Positioning System (GPS) has completely taken over the scene of navigation, probably for good reason. The technology behind them has become so advanced and accurate that there is little room for argument that they are a superior means of navigation, except for one. The one argument is the reason why all this other information is still valid and very worth learning. Water is everywhere in the world of outdoor sports, and there is no garauntee that a GPS will survive any amount of time in the wild. The fact of the matter is that any true survival situation will most likely not give you a convienence like a GPS unit, so learn how to navigate with AND without it. If you are in a survival situation, use GPS to confirm your position only, conserving battery life as much as possible and be sure to select area that will provide maximum satellite reception.
CONCLUSION
The more one learns about navigation, the easier it is to see that there is very little reason to ever be “lost” in the wilderness. Even if we don’t have the latest GPS unit to tell us where we are down to the foot, we can use minimal resources to find our way through most any terrain. With as little as our own two eyes, a stick or two and the elements described above, any one with the know how in this paper should have no troubles finding their way from one point to another. Whether you use the stars, the sun, a compass or a GPS, there are resources everywhere to get us from point A to point B.
