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FieldGrid

How can I use my phone as a search and rescue GPS?

FieldGrid shows your live position as an MGRS or UTM grid, the same systems a paper topographic map and most SAR teams already use, and lets you save, share and import waypoints between phones as GPX files. The position itself needs no signal at all; only the map picture sitting behind it does.

4 min read · Updated 2026-09-23

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SAR runs on grids, never addresses

A search area gets described on a topographic map with MGRS or UTM grid lines, not street addresses. A phone that only gives you a generic map pin leaves you unable to plot it on that same map or call it over the radio the way everyone else on the team already does. FieldGrid just gives you the number the map is already printed with.

Give your position as a grid

  1. On the Map tab, open the gear then Settings > Coordinate format and set Primary to MGRS or UTM, whichever your team uses.
  2. Read the top line once the ± accuracy figure settles, then tap it to Copy, or press and hold to Share it.
  3. For a radio call, open Tactical tools > POSITION — RADIO FORMAT, or tap the speaker icon on the map, to get your 8-digit MGRS spelled out in the NATO alphabet, ready to Copy or Share.

Mark a point and pass it on

  1. Press WP+ at a point you want to record, such as a last-known position or a clue, or press and hold the map to drop one where you are looking.
  2. Give it a Name and a Category (General, OP, LZ, HQ, CP, Rally, contact, hazard, medic, supply) in the Waypoints tab.
  3. Tap the point's Copy or Share button to pass the grid as text, or use Select then Share to send several as a GPX file.

Exchange waypoints between phones as GPX

GPX is a plain file format that most mapping tools, and any other FieldGrid phone, can read without fuss. One teammate exports, the other imports, and that's the entire mechanism.

  1. Sender: Waypoints > ••• menu > Select, pick the points, then Share (or, with Pro, Export all (GPX)).
  2. Send the .gpx file over AirDrop, a messaging app, or any share sheet.
  3. Receiver: open the file with FieldGrid, then use Select all and Import in the Import GPX sheet. Only waypoints come across, not tracks or routes, and it still respects the free waypoint limit.

Base grid, LKP grid

Say your base sits at one grid, and a last-known position (LKP) report comes in with another.

Base and last-known position
PointMGRSUTM
Base11SMT 3366 845611N 433665 3784566
LKP11SMT 3545 865811N 435454 3786586

Save the LKP as a waypoint from the grid you were handed, and back at Base the Waypoints list shows it at a true bearing of 041° and a distance of 2.7 km, the same great-circle maths FieldGrid runs for any saved point.

Limits to know before relying on this in a real search

  • No live sharing between phones. FieldGrid has no account and no iCloud sync, so a GPX file, or someone reading a grid aloud, is how a point actually moves from one person to another, never automatically.
  • Free holds 5 waypoints, plus one per rewarded ad; a team logging clues across a long search will want Pro's unlimited waypoints fairly quickly.
  • The map background is Apple Maps, needs a connection, and has no offline topographic layer, so away from signal you trust the grid numbers, not the drawn map underneath them.
  • GPX import only brings in waypoints, never tracks or routes, and there's no in-app import button at all: you open the file with FieldGrid from Files, AirDrop or a share sheet.
  • Positions read to the accuracy of the phone's own GPS fix, shown as ± metres next to the grid, never a surveyed or professionally calibrated reading.

Questions and answers

What's the best GPS for search and rescue?
No single answer; dedicated handheld units exist for exactly this reason. FieldGrid's pitch is simpler: the phone already in your pocket can show the same MGRS or UTM grid your map uses, work with no signal for the position itself, and hand points to teammates as GPX, no extra device required.
Can I track my team members' GPS positions in real time?
No. No account, no server, no live sharing between phones at all. Each person's position stays on their own device until somebody deliberately shares a grid as text or a GPX file.
Does a search and rescue GPS app need cell signal?
Not for the position itself; that comes off GPS satellites and gets calculated on the phone. The map picture behind it is Apple Maps and only shows tiles already cached once you lose the connection.
Can I bring in a coordinate a teammate sends me?
Yes. Type it in by hand if it's a single grid or lat/long, or import a .gpx file they exported from their own FieldGrid or another mapping tool; import only reads waypoints, never tracks or routes.

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