Compass Triangulation

Find a position on the map from nothing but compass bearings.

Triangulation is the art of estimating an unknown position by measuring the bearing and/or distance of two or more locations. This technique has been used for thousands of years and has many applications ranging from estimating the position of spacecrafts to finding the epicenter of an earthquake, locating distress beacon signals, and is also used in land navigation to estimate one's location.

Compass Triangulation is a resection tool: take two or more magnetic compass bearings from known observation points toward the same distant object, and the app calculates exactly where that object is — with a confidence rating and an uncertainty radius, not just a single guessed point. It's built for search-and-rescue teams, land surveyors, wildland firefighters, hunters, and anyone else who needs to turn "I saw it from here, at this heading" into an actual set of coordinates.

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Compass Triangulation User Manual

By accessing this application you hereby agree to the terms of our Software Disclaimer and of our Privacy Policy.

Free Features

Unlimited bearings. Add as many sight lines as you have observation points — there's no cap encouraging you to upgrade.
Multiple ways to add a bearing: type it in manually, capture it live from GPS + device compass, or import one someone else shares with you via QR code or link.
Automatic intersection calculation. With two or more non-parallel bearings, the app computes the averaged intersection point, a triangulation confidence rating (based on the crossing angle between bearings — shallow angles mean less certainty, and the app tells you so), and an estimated uncertainty radius in real-world units.
UTM and MGRS coordinates, alongside plain latitude/longitude, since that's what many field teams actually work in.
Nearest-address lookup for the computed intersection point.
JSON export/import of your full bearing set, for backup or moving between devices.
QR code and link sharing, including magnetic declination, so a triangulation computed on one device resolves to the same real-world point on another — regardless of what declination is set there.
Manual magnetic declination entry.
Street and satellite base maps.
Full data backup and restore, exportable as a file you control — not dependent on whatever your device's backup settings happen to be.
Tap a shared link and, if you already have the app installed, it opens directly with the data loaded — no detour through a browser.

Pro Features — What You're Unlocking (only available in IOS Application)

Compass Triangulation Pro is a one-time purchase. No subscription, no recurring charge. Here's what it actually buys you, and why each piece matters:

GPX Export Your bearings and computed target, in a format every serious mapping and GPS tool already understands — Garmin devices, Gaia GPS, CalTopo, QGIS, whatever your team already uses. Triangulation inside the app is the start of the workflow, not the end of it; GPX export is what lets the result actually go somewhere.

Saved Session Library Save a full triangulation session — bearings, computed intersection, everything — under a name, and come back to it later. Useful the moment you're running more than one search or survey at a time, or need to revisit a prior result without re-entering every bearing from scratch.

PDF Field Report A generated, shareable report: the map with all bearing lines and the computed intersection drawn on it, a table of every bearing (with both the raw compass heading and the true-north-corrected heading — you don't have to do that math by hand), coordinates in three formats, the confidence rating, the uncertainty radius, and the nearest address. This is the difference between "I have a point on a map" and "I have something I can hand to an incident commander or attach to a report."

Live Magnetic Declination Declination isn't a fixed number — it drifts over years and varies by location. Instead of looking it up and typing it in by hand, Pro fetches the current value automatically from a live geomagnetic model based on your GPS position, and re-fetches it if you move. One less thing to get wrong under pressure.

CAP Search Grid Overlay Standard Civil Air Patrol search-grid lines, overlaid directly on the map. If your team already coordinates using CAP grid references, this puts that reference system right where you're already working instead of a separate paper chart.

Offline Maps Draw a rectangle over the area you're about to operate in, pick how much extra zoom detail you want, and download it — tiles and all — before you lose signal. This isn't a passive cache that might or might not have what you need; it's a deliberate "I'm going here, prepare this area" action, with a real size estimate before you commit and a live readout of what's actually stored on your device afterward.

Keep Screen Awake Locks the screen on while you're actively triangulating, so a timeout doesn't interrupt you mid-fieldwork.

By accessing this application you hereby agree to the terms of our Software Disclaimer and of our Privacy Policy.

Open Source Acknowledgments

This app uses the following open-source libraries:

html5-qrcode — mebjas (Minhaz Av). Apache License 2.0. https://github.com/mebjas/html5-qrcode

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