Geofence around an area
A fence a set distance around a point, route, or area, with an optional inner warning fence, its area and perimeter, and any waypoint that falls outside.
Planning and education aid. Not for primary navigation. Full disclaimer
Experimental: not yet fully verified. How results are checked
The fence encloses 0.070008 km². 1 waypoint is outside it.
- Caution:Outside the geofence: waypoint 3 by 12.0 m.
| Waypoint | Status | Beyond the fence |
|---|---|---|
| 2 | past the warning fence | 7.8 m |
| 3 | outside the geofence | 12.0 m |
- Fence perimeter
- Waypoints outside
- Waypoints in the warning zone
- Largest measured fence error
Provenance
- Computed by
- drone.mission.geofence 1.0.0, core 0.1.0
- Model
- The fence is the round geodesic buffer of the area (geometry.buffer.geodesic): every point within the distance of it. A waypoint is outside when its geodesic distance to the area exceeds the fence distance, and by exactly the difference (Karney 2013)
- Accuracy
- The fence is within 0.1% of the distance or 0.5 m, as measured; waypoint distances are exact geodesic distances to the area
- Notes
- 2 shown with the answer
- Cites
- Karney, C. F. F., Journal of Geodesy, Algorithms for geodesics
Something look off?
How we got thisFormula, worked example, sources, and proof
Model: The fence is the round geodesic buffer of the area (geometry.buffer.geodesic): every point within the distance of it. A waypoint is outside when its geodesic distance to the area exceeds the fence distance, and by exactly the difference (Karney 2013)
Accuracy: The fence is within 0.1% of the distance or 0.5 m, as measured; waypoint distances are exact geodesic distances to the area
Worked example: A 50 m fence around a field, with a waypoint 12 m outside. Source: add-drone-suite waypoint-outside-fence scenario.
You enter
- Area, route, or point
- 40, -105 40, -104.998 40.0015, -104.998 40.0015, -105
- Fence distance
- 50 m
- Warning fence
- 30 m
- Waypoints to check
- 40.00075, -104.999 39.99966, -104.999 39.999442, -104.999
You get
- Fence area
- 0.070008 km²
- Fence perimeter
- 0.989 km
- Waypoints outside
- 1
- Waypoints in the warning zone
- 1
- Largest measured fence error
- 0.122 m
Review: Not yet independently reviewed by a Part 107 remote pilot.
Last verified: 2026-09-18, when a maintainer last confirmed this tool's sources at the issuer. See the sources ledger.
Status: version 1.0.0, core 0.1.0. See this tool in the verification report.
Checked against: 10 golden test vectors (download the test vectors, each with its source and tolerance). See how results are checked and every source.
Sources
- Algorithms for geodesics, Karney, C. F. F., Journal of Geodesy, Vol. 87, No. 1. pp. 43-55 (direct and inverse geodesic problems).
Experimental means this tool has not yet met the stable bar: at least 20 golden vectors, differential tests, and an independent worked example.