Precise USNG coordinates from your mobile browser
In support of the USNG Emergency Location Marker (ELM) system, a FREE Progressive Web App (PWA) has been developed which uses the GPS chip of smartphones and tablets (models since approximately 2011) to generate a USNG position display. Unlike traditional apps, there's nothing to download from an app store - simply visit USNGApp.org in your mobile browser to instantly access precise location coordinates. The display mimics Emergency Location Markers (ELMs) used by first responders nationwide and works on both iOS and Android devices.
Example display
To access and use the application, use the following steps:
1
Enable GPS/GNSS location services on your mobile device in the settings.
2
Allow your browser (Safari, Chrome, etc.) to access location services when prompted.
3
Move outside for optimal GPS satellite reception.
4
Open your browser and navigate to USNGApp.org (requires internet for first use).
5
Save the page as a bookmark/favorite for offline access later.
6
Wait for GPS fix. Blue numbers indicate high confidence while red numbers are lower confidence estimates. Check the orange status text for current accuracy.
Example display highlighting the blue and red numbers along with the orange status text referred to in Step 6.
Understanding Your Cooridnates
The table below shows how USNG coordinates provide different levels of precision depending on how many digits you use. More digits mean greater accuracy.
| Number of digits | Accuracy level | Best use case |
|---|---|---|
| 8 digits | 10 m | 911 location reporting and Emergency Location Markers (ELMs) |
| 6 digits | 100 m | Helicopter landing zones, search area coordination, and tactical operations |
| 4 digits | 1,000 m | USGS topographic maps and multi-team coordination across terrain |
| 2 digits | 10,000 m | Regional planning maps and state-level overview for broad area reference |