Geofences
A geofence is a boundary the app watches for you. Cross it and your phone tells you — useful for staying inside a work area, keeping clear of a hazard, or knowing when you have reached a site.
Three shapes
| Type | Defined by | Typical use |
|---|---|---|
| Circle | A centre and a radius (10–1 000 m) | A site, a well, a base station |
| Polygon | Three or more corners | A plot, a concession, a no-go area |
| Corridor | A line and a buffer width (10–1 000 m) | A road, a pipeline, a transect |
Creating and editing
Data › Geofences › Add Geofence opens the editor: a map with a panel you can pull up. Pick the type on the map toolbar, then place the shape by tapping the map, from your GPS position, from a GPS average, from the crosshair, or by pasting coordinates. Polygon corners and corridor points can be dragged; the hollow handle between two points inserts a new one; double-tap a handle to remove it. Undo and Reset are in the panel.
Below the geometry, choose whether to alert on entering, leaving, or both, and optionally write the message for each. Tapping a geofence card in the list opens its options: edit, activate or deactivate, delete.
Monitoring
Turn on Background Monitoring at the top of the Geofences tab. Tavak then watches your position even when the app is in the background or the screen is off, and raises a notification when you enter or leave an active geofence.
- Monitoring needs location permission, and on Android 13 and later notification permission; the app asks for both when you turn it on.
- Fixes with poor accuracy are ignored, and a boundary has to be crossed by a small margin before the state changes, so standing near an edge does not produce a stream of alerts.
- If you turn monitoring on while already inside a geofence, that is not reported as an entry.
- Monitoring resumes by itself after the phone restarts, as long as the switch was on.
- You can always turn it off, even after every geofence has been deactivated or deleted.
Import and export
Geofences can be downloaded or shared as GeoPackage, Shapefile (ZIP) or GeoJSON, and imported from the same formats — from Tavak or from QGIS. Circles are exported as points with a radius attribute, corridors as lines with a buffer, polygons as polygons; enter/exit settings and messages travel with them. Importing a file you exported earlier recognises the geofences already on the device and skips them.
Projected shapefiles are transformed using their .prj. Out-of-range radii are clamped to 10–1 000 m. Up to 1 000 geofences are read from one file.
When it doesn’t work
- The switch will not turn on
- The message under it says why: location permission, or notification permission on Android 13+. Grant it in system settings and try again.
- No alert arrived
- Check the geofence is active and that its trigger (enter/leave) is on. Battery optimisation on some phones stops background services — exclude Tavak from it.
- Alerts fire repeatedly at the edge
- You are within GPS error of the boundary. Move a few metres in; the margin handles normal jitter but not standing exactly on the line.