Can you get from your current location back home without using a GPS? What if your regular route is blocked off and you need to go around? And worse, what if you can’t use your car at all? Pretty much anybody can use the Maps app on their phone to follow a GPS-created route from your current location to your destination. But if you have no service or worse – if the networks are all down, you should know how to follow a map on the roads, and using a compass if you need to go off-road. This article will discuss the basics of land navigation, which is defined as “the discipline of following a route through unfamiliar terrain on foot or by vehicle, using maps with reference to terrain, a compass, and other navigational tools.” I will follow this up with more advanced skills as I am able to find time to put my thoughts down on paper.
Definitions
Azimuth: The direction you are heading, measured in degrees from 0 to 360 on the compass. The opposite direction, to return to your starting point, is called a Reverse Azimuth, or Back Azimuth.
Cardinal Points: The main four directions on a map (North, South, East, West).
Compass: A compass is an instrument used for navigation and orientation that shows direction relative to the geographic cardinal directions.
Baseplate Compass or Orienteering Compass: Often used while placed flat on top of a map, so you can align the compass to your direction of travel and plan your route.
Geometric Compass: Used often in Geometry class in high school or college, and by engineers, but are also used for orienteering to measure distances.
Lensatic Compass: Used mainly while on the move, can use the slit in the lid to line up your destination while using the lens to view the directional markings on the compass body.
Compass Rose: Used to identify direction. On a map, this shows orientation layout, where on a compass, this moves to show the direction you are traveling.
Contour Lines: Marks elevation on a map. Every 5th line is darker and has a marking with the elevation in feet above sea level.
Grid North: The direction on a map that is listed as North on the compass rose.
Intermediate or Ordinal Points: The points in between the Cardinal points (Northeast, Southeast, Southwest, Northeast).
Latitude: Lines drawn on a map going east to west, and measure distance from the equator.
Longitude: Lines drawn on a map going north to south, intersecting at the poles.
Magnetic North: The direction a compass shows as North. In Rhode Island, this is approximately 14 degrees West from True North. This moves often and you should make sure your maps are recent so the value is closer to accurate.
Map Legend or Map Key: The area of a map that contains the compass rose, scale, and other markings.
Navigational Charts: A map used for either water or air travel that indicates travel hazards, like submerged rocks or routine flight paths.
Scale: Shows the relationship between distances on the map to distances on the ground.
Street Map: A map of a city, town, or state, showing the positions and names of roads.
Topographic Map: A map that shows large scale details and elevation changes. Primary mapping agency in the US is the US Geological Survey (USGS).
True North: The direction on a map that points directly at the north pole of the planet.
Basic Processes
Orient a map: Line the paper up to the real world
In order to know what direction you need to go, you will need to make sure your map is aligned North to South. If you just put a map flat on a table and start taking readings, how will you know that 110° on your map is actually 110° in the real world? To do this, we need to orient the map, which is a fancy way of saying we are aligning the map with the real world. This is a pretty simple process, if you understand what we are doing, and know what the provided markings tell us.
As shown above, there is a map legend with the compass rose that identifies true north and magnetic north (and sometimes grid north). We need to ensure that, before we read our azimuths, we ensure magnetic north on the map is the same as magnetic north in the real world as measured on the compass. To do this, start by placing the map on a flat surface with no metal pieces. Since a compass reads magnetic waves, the steel or aluminum frame of a table can actually throw off a reading. Next, locate the Magnetic North indicator arrow and alight the side of the compass next to this lne. Finally, spin the entire map and compass together until the M.N. arrow on the map is pointing in the same direction as the North arrow on the compass.
Once you have your Magnetic North marking aligned with your Magnetic North compass reading, your map is now set up so any readings you take will now be accurate.
Navigate: Getting from point A to point B
Draw a line from your starting point to your end point, which is your direction of travel. Find the azimuth in degrees you need to walk by using your baseplate/orienteering compass. Without moving the map out of alignment from the step above, line the compass up with your travel line. Turn the dial on the top of the compass so that the arrow is aligned with the compass needle. Now that the compass is set, you can read the number at the top of the compass.
Using the wire on the front of the compass, locate an object directly in your path – this could be a specific tree, or a unique rock. Make sure it is something that you won’t lose sight of while you’re walking towards it, or you will start to go off course. Walk directly to the object you located, counting your paces as you go. When you get to your end point, start over with the compass, find a new point, and continue walking in that direction. Repeat as many times as necessary until you arrive at your destination.
Measuring distance on the map: How far are you going?
How far does the map say you have to go? The legend has a scale to measure distances on the map. Most baseplate compasses also have a ruler on the side that you can line up with each other, and with your path of travel. If you have one, a geometric compass can be used to measure the distance as well. If it expands to the full distance, and that is less than the maximum length on the scale, then you can do it in one go. If not, you can measure out in pieces based on a unit on the scale.
From the images above, we can see that this leg of the route is around 8500 feet (1.6 miles) at 315°, which is perfectly Northwest.
Measuring distance in the real world: Know your stride and pace
When walking outside with no electronic devices to assist, we typically measure distance based on our stride length. This is the distance you move in two steps – right foot to right foot (or left to left, if you prefer). Your pace is the time it takes you to walk a set distance. Most adults pace is around 4 to 5.5 feet per step (left foot to left foot). This will vary based on height – specifically leg length – and gender. Men typically take longer strides than women, and are also, on average, taller. Adult women, on average, have a stride length of around 51 inches, where men average closer to 60 inches. But you will want to know yours specifically. As you age, you typically shorten your stride as well.
To measure your average stride length, set up a course 100 yards long (or visit a local high school or college football field). Walk at a normal pace from one end to the other, starting with your dominant leg. Count one each time your non-dominant foot hits the ground. At the end, your total is how many strides it takes to walk 100 yards. From this, you can calculate up or down how many steps or strides in any set distance. As an example, the average man will walk this distance in 60 strides, 120 steps. This knowledge can be used to calculate that you would walk a mile in 1,056 strides (2,112 steps). Knowing this, you can measure distance by counting how many steps you are taking. This is important to know where you are on your map after you start walking and don’t have any solid landmarks to help mark your location.
Note that you will need to adjust your pacing on uneven ground. You will take shorter steps over uneven or rocky terrain where you take shorter steps. When going up or down hills, while the length of your stride may not change – unless the hill is very steep – your forward movement will be less, as some of that stride is up or down. These changes are something you will have to be able to estimate and learn over time.
Side-step: Go around a large obstacle
When you encounter a large object in your way, like a cliff or a body of water that you cannot go through, you will need to go around it. Take a note of your current location on the map, then take a compass reading along a clear path. Make note of the angle, and walk that path, keeping note of the distance you travel in that direction. When you get around the object, find and mark your new location on the map (angle plus distance from your last reading). Take another reading back towards your destination.
If you are travelling a specific distance forward, and are unsure of your ability to measure forward distance while travelling on a non-direct route, you can make a series of 90 degree turns, so that the distance walking around the obstacle will not add forward movement. Make a note of the distance walking sideways, so you can walk the same distance back once you move forward past the blockage. Once past, return to the original course by walking the same distance in the other direction. This does take more time, and you end up walking further in the end, but it will keep you on your original course. This is not normally required, unless there is a specific reason to maintain a straight line the entire way to your destination.
There are more advanced methods of creating a path from start to finish other than straight lines or basic avoidance by using waypoints. This will take you on a longer journey, but is useful for avoiding tough obstacles, making the trip easier and often faster. That is for a more advanced article, but I have included a couple sample images here to give you an idea of how that will look. Let me know if this is something you are interested in learning more about, and I’ll add it to the priority list.
Reading Map Symbols
USGS topographic maps use standard symbols and colors to designate different features. You can use this key to identify almost every ground feature that you will come across while out in the wild.
- Black – man-made features such as roads, buildings, etc.
- Blue – water, lakes, rivers, streams, etc.
- Brown – contour lines, sometimes smaller or unpaved roads
- Green – areas with substantial vegetation (could be forest, scrub, etc.)
- White – areas with little or no vegetation; white is also used to depict permanent snowfields and glaciers
- Red – major roads and highways; boundaries of public land areas
- Purple – features added to the map since the original survey. These features are typically based on aerial photographs but have not been checked on land and updated on existing maps. After a new full mapping survey, the new maps will have these in the standard colors
