Some of the best detecting spots are in places where your phone gets zero signal. Old farmland, remote beaches, woodland — no bars, no data, no map loading. Offline maps solve this by downloading the tiles you need while you still have Wi-Fi.
USGS Maps for Offline Use
Pro offers two sources for new offline downloads in the United States. Download your map while you have an internet connection, then use it on the detecting trip.
- USGS Imagery provides aerial imagery for viewing field shapes and the surrounding terrain.
- USGS Topo provides the current USGS topographic basemap.
The available sources depend on the area you select. The app shows which sources you can download for that location. Packs already stored on your phone can be viewed in Offline Maps.
How to Download a Map Pack
- Open the Offline Maps screen from the More tab
- Pan and zoom the map to the area you want to detect
- The download radius adjusts automatically based on your zoom level — zoom in for a focused pack, zoom out for a wider area
- Select which tile source you want (you can download multiple sources for the same area)
- Tap download and wait for the tiles to cache
Managing Your Map Packs
Each download is saved as a named pack. You can see how much storage each one uses, rename them to match your detecting sites, and delete old ones you no longer need. Maps are stored locally on your device, so they survive app restarts and don't count against any cloud storage.
Storage Considerations
The estimated download size depends on the selected source, area, and quality. Check the estimate before downloading and use Wi-Fi for larger packs. You can delete packs from Offline Maps to free storage.