Skip to main content

Power safety check

Generators, fuel, heaters, batteries, and high-load devices can create fire, carbon monoxide, shock, and ventilation risks. Follow manufacturer manuals, local codes, and official safety guidance before use.

Backup Power

How to Shoot an Azimuth When GPS and Power Fail

Learn two practical azimuth methods using a baseplate compass and map so you can navigate when GPS or backup power fail. Step-by-step guidance, tradeoffs, and s

Quick Answer

Both steps you’ve seen — putting the needle 'in the shed' while pointing at a feature, and aligning the orienting lines with map gridlines after placing the compass on the map — are parts of the same overall process. One is how you capture the magnetic bearing in the field; the other is how you transfer and orient that bearing to the map. Learn them in order, practice with known reference points, and keep a charged GPS and spare power as a complementary layer, not the sole plan.

Confidence: editorial reviewSources reviewed: 1

Key Points:

  • Take the bearing in the field by pointing the compass at a feature and rotating the bezel until the needle is aligned in the shed.
  • On the map, place the compass edge through the feature and your roughly known position, then rotate the whole compass until orienting lines match map grid north; draw the line to triangulate.
  • Treat GPS and power banks as layered backups; practice map-and-compass drills regularly and test batteries and equipment.

Last updated: 2026-07-24

If your GPS or backup battery dies, a map and compass let you find your location by shooting bearings to visible features. This article explains the two common transfer steps you’ll see online, why they differ, and how to use both safely and reliably.

Direct answer — why two methods look different

The apparent discrepancy comes from two distinct steps: capturing a magnetic bearing in the field (needle in the shed) and transferring that bearing onto the map so the compass is aligned with map north (orienting lines on map gridlines). They are not mutually exclusive methods — they are consecutive actions in a single workflow.

When someone describes 'put the red in the shed' they explain how to read the bearing on the dial while pointing at the feature. When another instructor says 'align the orienting lines with the grid' they are describing how to place that bearing on the paper map so you can draw a line.

  • Step 1: Point at the feature, rotate bezel so the needle sits in the shed — read the bearing.
  • Step 2: On the map, align the compass edge through the feature, rotate the whole compass until orienting lines are parallel to map north, then draw the line.
  • Repeat with a second feature to triangulate your location.

Prioritized action sequence (what to do today)

Start simple: practice one complete bearing-transfer now at home so you understand the two-step flow.

Then add redundancy: check your GPS and backup power state and pack the following for your next trip.

  • Today’s 10-minute drill: take a paper map of your area, pick two visible distant landmarks (or use printed photos), go outside, use a baseplate compass to shoot an azimuth to one landmark, transfer it to the map, repeat for the second, and confirm where the lines intersect.
  • Verify your GPS and phone have current maps and at least one charged external battery; note how long the battery actually holds a charge under expected use.
  • Pack a small repair kit (spare compass, pencil, waterproof paper) and a printed map of your area in an accessible pocket.

How to shoot an azimuth step-by-step (field-to-map)

Follow these steps slowly until they become second nature. Use a mirrored baseplate compass or standard baseplate with clear orienting lines.

Be explicit about magnetic declination in your area and whether you are reading magnetic or grid bearings.

  • 1) Identify two or more visible features you can both see and find on the map (peaks, towers, road intersections).
  • 2) Point the direction-of-travel arrow at the feature, rotate the bezel until the magnetic needle sits in the orienting arrow ‘shed’ (red over red). Read the bearing at the index.
  • 3) On the map, place the compass edge so it passes through the map location of the feature and your estimated position (or at least through the feature).
  • 4) Rotate the entire compass (not the bezel) until the orienting lines inside the bezel run parallel to the map’s north-south gridlines (or true north if using grid bearings).
  • 5) Draw a straight line along the edge of the compass from the feature; repeat with another feature. Where the lines cross is your location.
  • 6) If your map uses grid (true) north, apply local declination corrections when converting magnetic bearings.

Equipment tradeoffs and systems thinking

Backup power changes how you prioritize tools. A fully charged GPS makes quick work of location fixes, but batteries fail and electronics can be damaged. A paper map and compass are low-cost, zero-power fallbacks, but they require skill and are slower.

Consider these tradeoffs when building a resilient navigation kit.

  • GPS + backup power: fast and accurate when charged; relies on satellites and working hardware; store backup batteries and a solar charging option if long-term use is expected.
  • Map + compass: always usable if dry; requires training in declination, bearings, and map reading; practice regularly and protect maps from moisture.
  • Redundancy: carry both and use procedures that let one system check the other (e.g., use a compass to verify a GPS waypoint).

Common failure modes and how to mitigate them

Knowing likely failures helps you plan and prioritize maintenance and drills.

Many failures are preventable with simple checks and habits.

  • Dead batteries: keep at least one separate external battery and a small solar panel for long trips; rotate and test batteries every 3–6 months.
  • Compass errors: magnetic interference from metal objects, electronics, or vehicle bodies can distort readings. Move clear of vehicles, metal backpacks, or exposed wiring before taking a bearing.
  • Map errors: carrying the wrong map scale or outdated maps can mislead you. Use the correct scale and verify map dates before travel.
  • Declination mistakes: failing to convert between magnetic and grid bearings causes consistent offset. Learn local declination and whether your compass has an adjustable declination feature.
  • User error: rushing, poor sighting, or not using obvious landmarks causes inaccurate lines. Slow down, re-sight each feature, and repeat bearings for confirmation.

How to test and maintain the system

Regular testing keeps both your equipment and your skills current.

Include hardware checks, paper checks, and skill drills in a recurring routine.

  • Monthly: check GPS device power cycles, verify external batteries hold charge, confirm phone map apps have offline maps.
  • Quarterly: practice a full navigation drill with compass and map in local terrain; shoot bearings to three landmarks and verify result against GPS or known position.
  • Annually: check compass for bubbles, smooth bezel rotation, and readable markings; replace if damaged. Replace paper maps if torn or waterlogged.
  • Before each trip: verify local magnetic declination from a reliable source and note it where you can see it on your map or compass case.
Start backup-power quiz — reader-supported PrepperDirect

Reader-supported recommendations are clearly disclosed. Buy only what fits your plan.

Continue with a backup-power comparison

Use the guidance above to decide whether this recommendation belongs in your plan. Compare fit before buying.

Check the recommendation

We may earn a commission if you buy through our link. This does not affect our recommendations.

Questions readers ask next

General educational information only. Follow current official guidance, manufacturer instructions, local rules, and qualified training for safety-critical decisions.