A bounded offline map
Download one supported regional package over Wi-Fi on iPhone before leaving. Grat validates the package and transfers a simplified copy to the Watch.
Grat is a focused hiking companion. Prepare a regional map on iPhone, then use the Watch for your position, walked track, elevation, distance, and recording controls—even when the phone stays in your pack.
Product status
Grat – Offline Watch Maps is preparing for App Store review. The Swiss Central Alps map package and source ledger are published; physical-device field and battery validation remain pending, and simulator results are not presented as hardware evidence. Existing /cairn web paths and Cairn technical map identifiers remain in place for continuity.
Read the privacy policyBuilt for one job
Grat keeps the trail essentials close and deliberately leaves out feeds, leaderboards, and training clutter.
Download one supported regional package over Wi-Fi on iPhone before leaving. Grat validates the package and transfers a simplified copy to the Watch.
See the map, current position, heading, and the line you have walked. Use the Digital Crown to move through a small set of useful zoom levels.
Start, pause, resume, and finish on Apple Watch. Once its map is installed, the Watch records location independently of the iPhone.
Switch to a clear metrics view for elapsed time, distance, and ascent. Barometric altitude is preferred when the Watch supports it.
Completed hikes sync back to iPhone for a track preview, summary, deletion, and GPX export through the system file exporter.
Grat lowers location and display work when paused or in Low Power Mode while keeping the map and track available.
Before, during, after
Allow location access, download the supported map over Wi-Fi, and let iPhone transfer it to the paired Watch.
Start a hike, follow your position and recorded path, then pause or finish without reaching for your phone.
When the devices reconnect, review the completed activity and export a standard GPX file if you want a copy elsewhere.
Quiet software
The v1 scope is intentionally narrow: a Watch map and a dependable record of one hike.
Location, altitude, and hike records are handled on your Apple devices. Grat uses Apple WatchConnectivity for the paired-device transfer and asks before writing a completed hiking workout to Apple Health. iCloud activity backup is optional and off by default.
See exactly how data is handledThe Swiss Central Alps package uses OpenStreetMap data and contour lines produced from Copernicus DEM GLO-30. Its exact package, manifest, source ledger, licences, transformations, and source offer are public.