Navigation and Signaling

Most wilderness emergencies begin as navigation failures. This chapter covers the map and compass skills that keep you found — including the one declination rule to learn — natural navigation for when the compass is gone, and how to signal rescuers so the search ends quickly.

Map and compass — the parts and the bearings

Know your compass: the BASEPLATE (with a ruler edge), the ROTATING BEZEL marked 0–360 degrees, the MAGNETIC NEEDLE (the red end points north), the DIRECTION-OF-TRAVEL ARROW, the INDEX MARK where you read bearings, and the ORIENTING ARROW and LINES (the 'shed' the needle sits in).

Taking a bearing FROM A MAP: lay the baseplate's long edge from your position to your destination with the travel arrow pointing AT the destination; holding the baseplate still, rotate the bezel until the orienting lines run parallel to the map's north–south grid lines with the bezel's N toward map north; read the index line — that is your map bearing.

Taking a bearing TO A VISIBLE TARGET: point the travel arrow at the target; rotate the bezel until the red needle is 'in the shed' (boxed by the orienting arrow); read the index line.

FOLLOWING a bearing: set the bearing at the index line, turn your whole body until the red needle is in the shed, and walk the travel arrow — re-checking often (every hundred paces or so), picking intermediate landmarks, and expecting lateral drift, because humans veer without references.

Two more tools: the BACK AZIMUTH (your bearing plus or minus 180 degrees — the way back), and PACE COUNTING (count double steps; calibrate on a known 100-meter course — typically 60–68 double paces — so roughly 1,000 double paces per kilometer).

Illustration: Baseplate compass aimed at a distant landmark: bezel, needle, orienting lines, and direction-of-travel arrow.

Declination — the one rule (NOAA)

Declination is the angle between magnetic north (where your needle points) and true north (where your map's grid points). It changes with location AND over time — never trust an old map's declination diagram; check NOAA's magnetic declination calculator for your area before the trip.

The rule, per NOAA: TRUE bearing = MAGNETIC bearing + DECLINATION, treating east declination as positive and west as negative. In plain words: going from a COMPASS bearing to a MAP (true) bearing, ADD east declination and SUBTRACT west declination. Going the other way — from a map bearing to the compass bearing you will walk — do the reverse: SUBTRACT east, ADD west.

Worked example: your map gives a true bearing of 90 degrees (due east) to the trailhead. Your local declination is 12 degrees WEST. The compass bearing to walk: 90 + 12 = 102 degrees. Set 102 at the index line and walk the travel arrow. If instead you sight a landmark at a compass bearing of 60 degrees with that same 12-degree-west declination, the true bearing to plot on your map is 60 − 12 = 48 degrees.

If your compass has adjustable declination, set the orienting arrow to the local value once per trip and read bearings directly as true — no math in the field.

Natural navigation — finding direction without a compass

These are standard land-navigation techniques (see U.S. Army FM 3-25.26, Map Reading and Land Navigation, and NOLS wilderness curricula) — approximate, but far better than guessing.

NORTH STAR (Northern Hemisphere): Polaris sits almost directly above true north. Find it with the Big Dipper's pointer stars — extend the line through the two outer stars of the bowl about five times their separation to reach Polaris.

SOUTHERN CROSS (Southern Hemisphere): extend the cross's long axis about 4.5 times to the south celestial pole, then drop vertically to the horizon — that point is due south.

SUN: it rises approximately in the east and sets approximately in the west; at local noon it stands due south (Northern Hemisphere) or due north (Southern Hemisphere). The WATCH METHOD: point the hour hand at the sun, then bisect the angle between the hour hand and 12 o'clock (1 o'clock during daylight saving) — that bisector runs north–south; in the Northern Hemisphere the direction away from the sun is north.

DEAD RECKONING: from a known point, record every leg you travel — bearing plus distance by pace count. Errors accumulate, so confirm against terrain features whenever you can.

MYTH CORRECTION: 'moss always grows on the north side of trees' is FALSE. Moss grows where it is damp and shady — often, but NOT reliably, on the north side. It is not a compass. Treat it as an unreliable folk indicator, and extend the same skepticism to moon-horn and anthill orientation claims.

Signaling for rescue — be findable

WHISTLE: the international distress signal is 3 BLASTS, pause, repeat (one standard: 3 blasts for one minute, one minute of silence, repeat until rescued). A whistle carries a kilometer or more at ~120 decibels and saves your voice. (Alpine regions use 6 signals per minute with a one-minute pause; rescuers answer with 3 per minute.)

SIGNAL MIRROR: the best daytime signal in sun — flashes have been spotted from aircraft at 35,000 feet. Hold the mirror near your eye, look through the sighting hole, and tilt it to flash your target (aircraft or the horizon); get to high ground. Only flat surfaces work — improvise with a CD, a phone screen, or a belt buckle.

GROUND-TO-AIR: lay out large geometric shapes in contrasting material — V means require assistance, X means require medical assistance, N means no/negative, Y means yes/affirmative; an arrow shows direction of travel. To a helicopter: both arms raised (Y) = need help; one arm up, one down (N) = no help needed.

FIRES: at night, 3 fires in a triangle about 75 feet apart on high, clear ground is the international distress signal; by day, make them smoky (green leaves or wet moss for white smoke; oil or rubber for black — calm, clear days only). WARNING: fire signals are dangerous in dry or windy country — genuine emergencies only.

TECHNOLOGY: a 406 MHz personal locator beacon (PLB) works globally via COSPAS-SARSAT and summons rescue directly; satellite messengers add two-way texting. Carry one in remote country.

Know how searchers work: searches expand outward from your last known position, and hasty teams check trails, roads, and watercourses first — so stay near one. Helicopters fly 500–1,000 feet up with line-of-sight only. If you hear aircraft or voices, signal IMMEDIATELY and CONTINUOUSLY — the window is short.

Illustration: Rescue signaling: signal mirror flashing at an aircraft, whistle, and V / X / Y / N / SOS ground symbols.