Why You Can't Rely on GPS Alone

GPS devices are remarkable tools — but they are tools, not substitutes for foundational navigation skills. Batteries fail in extreme cold. Devices get dropped in rivers. Satellites lose signal in deep canyons. The expeditioner who cannot navigate without a screen is an expeditioner who is one dead battery away from a serious emergency.

The following skills form the backbone of reliable wilderness navigation and should be practised until they are second nature.

1. Reading a Topographic Map

A topographic map represents the three-dimensional landscape in two dimensions using contour lines. Each line connects points of equal elevation, and the spacing between lines tells you the steepness of the terrain.

  • Close contour lines = steep terrain (cliffs, ravines)
  • Widely spaced lines = gentle slopes or flat ground
  • V-shapes pointing uphill = valleys or stream gullies
  • V-shapes pointing downhill = ridgelines or spurs

Spend time before any expedition studying your map until you can visualise the terrain it depicts. Practice correlating what you see on the map with what you see in the field.

2. Using a Baseplate Compass

A quality baseplate compass (Silva, Suunto, or similar) should be part of every expedition kit. The core skill is taking and following a bearing:

  1. Place the compass on the map with the direction-of-travel arrow pointing from your current location to your destination.
  2. Rotate the compass housing until the orienting lines align with the map's north lines.
  3. Add or subtract magnetic declination for your region (check your map legend).
  4. Hold the compass level, rotate your body until the red needle aligns with the orienting arrow.
  5. Walk in the direction the travel arrow points, using intermediate landmarks to stay on bearing.

3. Triangulation: Knowing Exactly Where You Are

If you're unsure of your location, triangulation lets you pinpoint it using two or more visible landmarks:

  1. Identify a visible landmark (peak, tower, lake edge) and take a compass bearing to it.
  2. Convert to a back-bearing (add or subtract 180°) and draw a line from that landmark on your map.
  3. Repeat with a second landmark at a different angle.
  4. Your position is at the intersection of the two lines.

4. Terrain Association

Terrain association is navigation by reading the land itself — matching what you see around you to the map. As you walk, continuously track your progress: note when you cross a stream, climb a rise, enter a forest. This running awareness of your position is the single most valuable navigation habit you can build.

5. Pacing and Timing

Know your pace count — how many steps it takes you to travel 100 metres on flat ground. Then adjust for slope and terrain. Combined with elapsed time and your known walking speed, you can estimate distance travelled with surprising accuracy when visibility is poor.

6. Natural Navigation Cues

As a last resort or useful supplement:

  • Sun position: In the northern hemisphere, the sun is due south at midday. In the southern hemisphere, due north.
  • Stars: Polaris (North Star) sits almost directly over the North Pole. In the southern hemisphere, use the Southern Cross.
  • Prevailing wind and vegetation: In many regions, trees lean consistently away from the prevailing wind direction — useful as a directional cue in whiteout or fog.

Practice Before You Need It

Navigation skills degrade rapidly without use. Before any expedition, run orienteering sessions in local terrain. Practice taking bearings, identifying your position, and navigating to waypoints. The time invested will pay off when conditions deteriorate and your GPS is at the bottom of a river.