How Emergency Services Use GPS Coordinates

When a hiker calls 911 from a wilderness location, the single most useful thing they can provide is a GPS coordinate. Emergency dispatchers, search and rescue teams, and air medical services all use GPS coordinates to locate and respond to incidents — but the format matters.

What Format Does 911 Dispatch Use?

In the United States, Enhanced 911 (E911) systems that receive a location from your phone transmit coordinates to dispatch in Decimal Degrees. Dispatchers typically relay this to field units in whatever format that agency uses — often DMS or MGRS for military-trained SAR teams.

Search and Rescue: MGRS and UTM

Many SAR teams in the US and NATO countries use MGRS or UTM for operational coordination. These grid systems make it easy to communicate distances and define search sectors on topo maps. A SAR team leader might say "the subject's last known is 10TER502548" and everyone immediately knows the zone and grid square.

What You Should Know Before Going Into the Backcountry

1. Know how to read your coordinates — before you need them. Turn on your GPS app, find the coordinates display, and know what format it's showing.
2. Know how to read them aloud — practice saying a coordinate out loud so you don't stumble under stress.
3. Have a backup — a Garmin inReach or SPOT device sends your coordinates automatically even without cell service.
4. Verify your location — cross-reference your app coordinate with a topo map before entering remote terrain.

The Most Important Thing to Remember

If you can only communicate one thing to emergency services, give them the coordinate in whichever format your device shows. Any format can be converted. Use our converter to translate any coordinate between DD, DMS, DDM, UTM, MGRS, Geohash, and Plus Codes instantly.