Geofence Generator & Builder
Create circular and polygon geofences with trigger definitions (enter/exit) and instant GeoJSON export for IoT, fleet tracking, and mobile apps.
The Geofence Generator allows developers and fleet managers to construct circular radius and custom polygon virtual perimeters on an interactive map. It generates production-ready GeoJSON boundary payloads, trigger rule definitions (enter, exit, dwell), and coordinates for AWS IoT Core, Google Cloud Fleet Engine, and Android/iOS geofencing SDKs.
Geofence Rule Definition
Ready for production export into AWS IoT Core, Google Cloud Fleet Engine, Traccar, or Android/iOS geofencing SDKs.
{
"type": "FeatureCollection",
"features": [
{
"type": "Feature",
"properties": {
"name": "Zone_Alpha",
"type": "circular_geofence",
"radiusMeters": 500,
"trigger": "enter_exit",
"centerLat": 37.7749,
"centerLng": -122.4194
},
"geometry": {
"type": "Polygon",
"coordinates": [
[
[
-122.41371750602534,
37.7749
],
[
-122.413744868787,
37.77534025147632
],
[
-122.41382669355366,
37.77577626309026
],
[
-122.41396219230808,
37.77620383581162
],
[
-122.41415006012318,
37.776618851881366
],
[
-122.41438848772921,
37.77701731446788
],
[
-122.41467517893797,
37.77739538615862
],
[
-122.4150073727564,
37.77774942591654
],
[
-122.41538186997646,
37.77807602414522
],
[
-122.41579506398517,
37.7783720355252
],
[
-122.41624297549836,
37.778634609305065
],
[
-122.4167212908833,
37.77886121675577
],
[
-122.41722540370138,
37.7790496755237
],
[
-122.41775045907056,
37.779198170647895
],
[
-122.41829140042063,
37.77930527203913
],
[
-122.41884301819066,
37.77936994825246
],
[
-122.4194,
37.7793915764206
],
[
-122.41995698180934,
37.77936994825246
],
[
-122.42050859957936,
37.77930527203913
],
[
-122.42104954092943,
37.779198170647895
],
[
-122.42157459629861,
37.7790496755237
],
[
-122.42207870911669,
37.77886121675577
],
[
-122.42255702450163,
37.778634609305065
],
[
-122.42300493601482,
37.7783720355252
],
[
-122.42341813002353,
37.77807602414522
],
[
-122.42379262724359,
37.77774942591654
],
[
-122.42412482106202,
37.77739538615862
],
[
-122.42441151227078,
37.77701731446788
],
[
-122.42464993987682,
37.776618851881366
],
[
-122.42483780769192,
37.77620383581162
],
[
-122.42497330644633,
37.77577626309026
],
[
-122.42505513121299,
37.77534025147632
],
[
-122.42508249397466,
37.7749
],
[
-122.42505513121299,
37.77445974852368
],
[
-122.42497330644633,
37.77402373690975
],
[
-122.42483780769192,
37.77359616418838
],
[
-122.42464993987682,
37.77318114811864
],
[
-122.42441151227078,
37.77278268553213
],
[
-122.42412482106202,
37.77240461384139
],
[
-122.42379262724359,
37.772050574083465
],
[
-122.42341813002353,
37.77172397585478
],
[
-122.42300493601482,
37.7714279644748
],
[
-122.42255702450163,
37.77116539069494
],
[
-122.42207870911669,
37.77093878324423
],
[
-122.42157459629861,
37.7707503244763
],
[
-122.42104954092943,
37.77060182935211
],
[
-122.42050859957936,
37.77049472796087
],
[
-122.41995698180934,
37.770430051747546
],
[
-122.4194,
37.770408423579404
],
[
-122.41884301819066,
37.770430051747546
],
[
-122.41829140042063,
37.77049472796087
],
[
-122.41775045907056,
37.77060182935211
],
[
-122.41722540370138,
37.7707503244763
],
[
-122.4167212908833,
37.77093878324423
],
[
-122.41624297549836,
37.77116539069494
],
[
-122.41579506398517,
37.7714279644748
],
[
-122.41538186997646,
37.77172397585478
],
[
-122.4150073727564,
37.772050574083465
],
[
-122.41467517893797,
37.77240461384139
],
[
-122.41438848772921,
37.77278268553213
],
[
-122.41415006012318,
37.77318114811864
],
[
-122.41396219230808,
37.77359616418838
],
[
-122.41382669355366,
37.77402373690975
],
[
-122.413744868787,
37.77445974852368
],
[
-122.41371750602534,
37.7749
]
]
]
}
}
]
}Geofence Builder Technical Specifications & Standards
WGS84 (EPSG:4326)
Standard global ellipsoidal coordinate reference system
WGS84 Geodesics
Sub-meter spatial boundary resolution
GeoJSON · KML · CSV · SVG
Compatible with QGIS, ArcGIS, Google Earth & CAD
100% Client-Side
Calculations run in-browser. Zero coordinate logging.
How to Use the Geofence Generator & Builder
Follow this step-by-step procedure to execute precise spatial measurements and export results.
- 1Choose fence geometry: Select Circular Radius or Custom Polygon.
- 2Define boundary: Adjust radius slider or click the map to add polygon boundary vertices.
- 3Set trigger rule: Specify entry, exit, or dwell event triggers.
- 4Export GeoJSON payload: Download the standard RFC 7946 GeoJSON or copy the JSON payload for your API.
Geodesic Precision vs. Competitor Mapping Approaches
Most legacy mapping utilities (such as CalcMaps and FreeMapTools) rely on planar Web Mercator projections or spherical approximations, causing significant mathematical distortion at higher latitudes. GeoMap Suite computes exact ellipsoidal geodesics on the WGS84 reference ellipsoid.
| Calculation Model | Mathematical Basis | Distortion on WGS84 | Standard Tools | Practical Application |
|---|---|---|---|---|
| Planar (Web Mercator) | Cartesian dx² + dy² | 10% to 200%+ error | CalcMaps / Simple map tools | Distorts drastically away from equator. Inaccurate for true distance. |
| Spherical Great-Circle | Haversine (R = 6,371 km) | Up to 0.5% (~5 km/1,000 km) | Basic Google Maps wrappers | Ignores Earth's polar flattening. Reasonable for rough estimates. |
| GeoMap Suite Ellipsoidal | Karney Direct/Inverse WGS84 | < 15 nanometers (<0.0001%) | GeoMap Suite | Geodetic surveying, maritime, flight paths & legal boundary analysis. |
Worked Example: Creating a 500-Meter Delivery Depot Geofence
A logistics manager configures an automated arrival trigger around an Amazon distribution center in San Francisco.
Input Parameters
- Center Coordinate
- 37.7749° N, 122.4194° W
- Radius
- 500 meters
- Trigger Event
- Enter & Exit
Computed Outputs
- Geofence Type
- Circular (64 vertices)
- Enclosed Area
- 785,398 m² (~194 acres)
- Payload Format
- Standard GeoJSON
Step-by-Step Mathematical Process
- Calculate geodesic circular polygon with 64 vertices at 500m radius.
- Assign metadata properties (fenceName: "Depot_SF_01", trigger: "enter_exit").
- Output standardized RFC 7946 Polygon FeatureCollection.
Understanding Your Results & Practical Interpretation
Circular vs. Polygon Geofencing
Circular geofences require only a center point and radius ($d \le r$), making them battery-efficient for mobile SDKs. Polygon geofences use point-in-polygon ray casting for complex property boundaries.
Practical Applications & Real-World Use Cases
Fleet Asset Tracking
Trigger automatic alerts when delivery vans arrive at loading docks.
Mobile App Location Triggers
Send push notifications when customers enter a retail store perimeter.
Mathematical Methodology & Geodetic Accuracy
WGS84 Geodesic Radius & Point-in-Polygon Ray Casting
Generates equidistant geodesic ring vertices using direct ellipsoidal solutions and standard WGS84 Cartesian coordinates.
Point_i = Geodesic.Direct(lat0, lon0, (i/N)·360°, r)Limitations & Boundary Conditions
- •Mobile device GPS battery optimization may cause a 5-30 second latency delay in triggering fence transition events.
Authoritative Reference Standards
Troubleshooting & Geographic Edge Cases
How many vertices should a circular geofence have?
Between 32 and 64 vertices provides an optimal balance of smoothness and low memory consumption on mobile devices.
Frequently Asked Questions
A geofence is a virtual perimeter for a real-world geographic area. When a location-aware mobile device or vehicle GPS tracker crosses this boundary (entering, exiting, or dwelling), software triggers automated notifications, check-ins, or telemetry events.