Navigation School

Direction is a door, Navigation is the key.

Directions. Our lives are spent giving and receiving them. Here, there. Right, left. Forward, back. Checking our bearings, making sure.
We humans have always navigated through our world: by landmark and water, sun and stars. The technology we employ changes, but wayfinding knowledge does not: if you don’t understand how to navigate, you’re still lost. Thus, the skill to navigate by map and compass—neither of which depends on advanced electronics or batteries—is crucial. Whether exploring a wild mountain range where the only available information is a printed map or the confusion of a foreign city. It can also be fun.
Over the years, Silva has become a reliable and trusted navigation partner among defense forces, expeditions to the remotest parts of the globe, and the orienteering and adventure racing communities. One reason for this vote of confidence is the Silva 1-2-3 System® that enables you to take and walk a bearing in an easy and accurate way. The popular system evolves this year with colour-coding on the Field 1-2-3 Compass, a new memory tool for both educational use and the infrequent navigator.
Whichever Silva product you choose, the first question is always the same: where are you going?

Magnetic Declination

When compass and map are used ­together it’s important to know the local magnetic declination (i.e. the difference between true North—where the map meridians point—and magnetic North—where the compass needle points). In areas with significant declination, adjustments must be made to walk a ­correct bearing; information concerning magnetic declination is found on the topographic map.

Positioning with Cross-bearings

It’s simple to plot a compass ­bearing onto a map by following the Silva 1-2-3 System® in reverse order. Take a bearing to an object in the field that you can also locate on the map. Place the compass on the map with the baseplate’s long side intersecting the object to which the bearing was taken. Draw a line along the baseplate, and your position is somewhere along this line. Repeat the procedure using another object that you can see from your current location and you’ll be at the intersection of the two lines. For best accuracy, use objects that are on a 90-degree angle from each other versus your location. For even greater accuracy, use three lines.

GPS Coordinate Scales

Use the GPS coordinate scales on the base plate to determine the coordinates of a known position on the map (or to determine the position of known coordinates on the map).

Planning a Route

Before heading out it is important to ­always plan your route. Your navigational skills, physical condition and choice of terrain will all affect your plan. Make sure you create a plan that fits you—it’s always better to play it safe than to take unnecessary risks.

Mirror Sighting Compasses

A mirror-sighting compass is at its best in open terrain where you must determine direction over long distances. Because you needn’t lift your eyes from the compass in order to look into the terrain, the direction determined with the Silva 1-2-3 System® becomes more ­accurate.

Judging Distance / Time

It’s good to have an understanding of how far along your route you’ve traveled, especially when walking a ­bearing according to the Silva 1-2-3 System®. This is normally done by checking ­objects that you pass, but in terrain where these don’t exist there are two other methods for judging distance: 1) clock—if you know your approximate speed (e.g., 4 km/h) you can easily calculate how long it should take to travel 3 km (45 minutes); 2) counting steps—if you know your approximate stride length (e.g. 0.8 m) count each step with your right foot; in this case it would take 62 steps to travel 100 ­meters, or 620 steps/km.

Attack Point

An “attack point” is a position on the map after which you have no ­significant terrain objects to follow—either to the ­final goal or to a new “hand rail” to ­follow. At this point you should use the Silva 1-2-3 System® to travel a bearing from the map.

Keeping Track of Position

By checking terrain objects you can ­easily keep track of position and also be ready when it’s time to change direction If you keep the map oriented North and your thumb on your current position, it will be easy (and quick) to find your last known ­position the next time you look at the map.