Maps

There are several types of maps you can buy, but we will focus on the Topographic map here, because this is the most popular map used for navigation through the backcountry. The Topographic map, sometimes referred to as a 'topo' map, uses lines to portray the shape and elevation of the land. The lines on a Topographic map are "Contour lines" and these are imaginary curved lines that run along the ground at equal points of elevation. The Contour lines make it possible to represent a three-dimensional elevation (mountain) in only two-dimensions (map). The distance between the contour lines is the "Contour interval" and it shows the difference in elevation (measured in feet or meters) between the two lines. This distance in feet or meters varies between maps and a scale is always on the map showing this measurement, usually at or near the bottom of the map. In the example below, Figure 1 shows how the contour lines are laid out from mountain to the map. The yellow or horizontal lines are different measurements above sea level and all equally spaced at a distance equal to the contour interval. The green or vertical lines are used to drop the elevations to the map. The resulting lines are the brown or circular lines which are the contour lines.

Figure 2 shows an example of how the contour lines represent grades in elevation, notice the difference between a steep hill and a gradual slope. On the left side of this mountain the contour lines are tighter together representing a steeper elevation, where the right side contour lines are much farther apart representing a smaller increase in elevation. Topographic maps also show the elevation measurements, in Figure 2 notice that every fifth line has a number, this is the measurement in feet or meters above sea level to which the contour line is equal to. Topographic maps also show several kinds of information that can be helpful to a person trying to navigate across land. Such as:

• man-made and natural elevations
• ground cover (vegetation: trees, bushes- usually green-shaded areas; water: rivers, lakes- usually areas and lines of blue; sparse vegetation: desert, rocks-usually white-shaded areas).
• map revisions: shown in purple-shaded areas or print along the bottom.
• park borders: represented by black dashed lines and shaded by brown, green, or gray.
• roads/trails: represented by varying line colors and thicknesses depending of type of road/trail.
• man-made objects: such as buildings which are usually small black squares.
• camping information: some maps have lean-to's, designated camping areas and other such information
• direction/distance: direction and distance two any two points or locations.
• angle of declination: described later.
• NOTE: be sure to check the legend for your maps coloring scheme.

An example of ground cover is shown in the upper-left corner of the contour lines. There is a small blue line that runs from the center of the contour lines (or top of the mountain) out until it leaves the diagram (or bottom of the mountain). This represents a small river or stream coming down from the mountain. Notice the contour lines around the stream, they seem to point straight downhill, they are representing a depression down to the water. Imagine walking up to the water and having to climb down a bank to get to the shore.

Compass

     There are three types of compasses, a compass that attaches to a map, a compass that attaches to your thumb (mostly used by orienteering people), and the third is a base plate or protractor compass which is hand held. We will discuss this type and it is pictured below in figure 3. On the compass, the big ring is the housing, and on the edge of the compass housing are the degrees or the bearing. North is 0°, east is 90°, south is 180°, and west is 270°. These degree marking are left off and replaced with a label of the actual direction which are called the cardinal points. In the center of the housing, you will see a red and white arrow which is the compass needle, and the red part of the arrow will always point north (as long as your compass is functioning correctly). There is a smaller circle on some compasses and this is just a magnifying glass in order to read map details easier. There is a very important line that run along the center of the compass and this line represents the direction of travel, and is called the, you guessed it, the direction of travel-arrow. Along the sides and in some cases along the front of the compass are scales that are equal to the most popular map scales so you can get distance measurements. Lastly, but not shown in Figure 3 is the string that is attached to the base plate, and it is referred to as the lanyard.

    Compasses work because the earth acts like a giant magnet, and like a magnet the earth produces magnetic lines of force. Compasses work by aligning their magnetized needle with the earth's magnetic lines. The magnetized needle has been set up such that it will point to what is referred to as magnetic north, which is not the same as geographic north or the north pole we are all familiar with. Magnetic and geographic north will be discussed later.
    As stated above a compass needle does not usually point due north, but at some angle east or west of north. This is because the earth's geographic pole is not the same as its magnetic pole. The direction to the earth's geographic pole is called true north and the direction to he earth's magnetic pole is called magnetic north. When you are using a compass you have to account for this difference between magnetic north and true north. The angle between true north and magnetic north is called the magnetic declination. On a typical topographic map, the magnetic declination is indicated as explained in the map reading page. At the bottom of the map near the center you will find a diagram with three lines and some angle information. Above one of the lines there is a star, the star indicates true north and points toward the top of virtually all maps. The line with the MN above it represents the direction to the north magnetic pole from the center of the map. Next to this line there is a degrees marking and this is the angle of declination. This angle indicates that your compass will point this number of degrees in the direction of the arrow of true north. The third line, labeled with GN, stands for grid north and will not be covered in this page.

Map and Compass

• place the compass on the map
• using the side of the baseplate that is parallel with the direction of travel-arrow, move the compass to the location where you are currently, placing the side directly over your location. If you dont know where you are now, go to the section on triangulation. We will call this location X.
• now place the location of your destination along the same side of the compass. We will call this location Y.
• A very important step is to make certain the direction of travel-arrow is actually pointing in the direction of travel. Meaning this arrow is pointing from location A (your current location) to location B (your destination).
• Now, keeping the compass firmly pressed against the map we are going to align the vertical (meridian) lines of the map with the orienting lines within the compass housing. Do this by holding the compass and map firmly together and rotating the housing until the two sets of lines are running exactly parallel with each other. Read the bearing from the compass housing and remember this number. A few things to note: you dont care where the compass needle ends up in this step, double-check that the compass didn't move while you rotated the housing, and be sure north is north. The last comment means to make sure the orienting lines are pointing to the north of the map. You may now let the map and compass separate, being careful not to move the housing.
• Now here is where the Magnetic North and True North explanation comes into play. In the previous step you oriented your compass to True North or north on the map. In order to get the correct bearing to your destination you must use Magnetic North. Here is how to acheive that. Look at the diagram near the bottom-center of your map, it shows the declination angle or angle between True North and Magnetic North. It will show True North (the line with the star) as a vertical line and Magnetic North (MN) as some angle left (West) or right (East) of the True North line.
• Read how many degrees this angle is equal to.
• If Magnetic North is pointing to the Left (West) then you will subtract the value of the declination angle you found in the above step from the value of the bearing reading you took two steps ago. And on the contrary, if MN is pointing to the right (East) of True North, you will add the two values together and this will give you your magnetic north bearing. An easy way to remember when to add and when to subtract is to use a little piece of paper and put a minus sign next to the west and/or a plus sign next to the east.
• Now you have to transfer this new angle to your compass. So carefully rotate the compass housing to the new magnetic north bearing.
• You are now ready to start your travels. Remember to point at something in your bearing line and to move toward it and you will reach your destination.

Triangulation

• Here you will learn how to find where you are on a map using the land or landmarks around you.
• Look around you and find two points on the earth; such as mountain peaks, where a trail crosses a stream or river, ponds, buildings, roads, etc..., and try to keep them within 180 degrees of each other.
• Take a bearing to each of these points. Point the direction of travel-arrow to the landmark and rotate the compass housing until the red end of the compass needle is in the red orienting arrow of the compass housing. Take your bearing reading and repeat for the second landmark.
• Open your map and find the two landmarks from which you took your bearings from.
• Put the compass on the map and one side of the compass (that is parallel to the direction of travel- arrow) on the first landmark, and transfer the bearing you read earlier. Meaning move the compass until the red end of the compass needle is in the red orienting lines of the compass housing.
• Now draw a line along that side of the compass.
• Repeat the procedure explained two steps before.
• Where these two lines intersect is your location on the map.

Navigating with a compass

    There are two ways you would navigate with only a compass. The first would be to get a bearing on an object and following that bearing until you reach your destination. The second is if you need to go in a certain direction, and you align yourself to find your destination.
    In the first way, the first thing you need to know is how to take a bearing. A bearing is a degree reading or direction from your position to another object.

1. Hold the compass horizontally level, enabling the needle to move inside the compass freely.
2. Aim the 'direction of travel-arrow' toward the destination, do this by rotating your entire body and the compass until the direction of travel-arrow is pointing directly at the destination.
3. Now rotate the compass housing until the red end of the needle lines up with the red orienting lines within the compass housing.
4. You can now read the bearing (the degrees) from the housing ring.
5. You can now start moving into the direction of your destination, being careful to stay on your bearing by looking at the compass as you travel.
6. An easy way to stay on course is to, get your bearing, and then using your bearing find a intermediate destination that you can clearly identify and which is fairly close to you. An example of this may be: you are trying to get to a mountain several miles away and you have gotten your bearing to the top. Using this bearing, you look ahead and see a tree stump in your bearing, move to the stump and look ahead again for another intermediate destination in your bearing. This allows you to move fairly quick through the woods or heavy brush, because you don't necessarily have to travel in a perfectly straight line. As you do by trying to follow the compass bearing by constantly looking at the compass as you walk.

    The second way to use a compass, if you needed to head North East to get to your destination.

1. Rotate the compass housing until the needed direction meets with the end of the direction of travel-arrow. In this case that would be half way between North and East or about 45 degrees.
2. Hold the compass horizontally level, enabling the needle to move inside the compass freely.
3. Rotate your entire body and the compass until the red end of the needle lines up with the red orienting lines within the compass housing.
4. The direction of travel-arrow is now pointing in the direction you need to travel and you can set off in search of your destination.

Note:

• Any metal objects near a compass can through off your readings, be careful of metal when taking bearings.
• Always make sure you are using the red end of the needle for north, if the other end is used you will be headed in the exact opposite direction as you wanted.