The GPS Location operation checks whether a coordinate falls within a circular geofence. The geofence is defined by a centre point (latitude, longitude) and a radius in kilometres. Distance is calculated using the Haversine formula.
Inputs
| Port | Type | Required | Description |
|---|---|---|---|
| > (Gate) | Any | No | When connected, a false or Nil value stops the path. See Gate Inputs. |
| Latitude | Integer or Float | Yes | Latitude of the point to check (-90 to 90). |
| Longitude | Integer or Float | Yes | Longitude of the point to check (-180 to 180). |
Outputs
| Port | Type | Default | Description |
|---|---|---|---|
| Out | Boolean | (unset until first valid run) | true if the point is within the geofence, false otherwise. |
Properties
| Name | Type | Default | Description |
|---|---|---|---|
| Radius (km) | Number | 1.0 | Geofence radius in kilometres (0.01—1000). |
| Latitude | Number | 51.509865 | Latitude of the geofence centre. |
| Longitude | Number | -0.118092 | Longitude of the geofence centre. |
| On Error | Combo | Stop this branch | Per-op On Error verb (Stop this branch / Continue with the last value / Continue with the fallback). See the Error Handling guide. |
State on Reload
The last computed Out value is preserved across restarts.
Gate check — If the Gate is connected and false or Nil, the execution path stops; outputs remain unchanged.
Validate inputs — Latitude must be a finite number in [-90, 90]; longitude in [-180, 180]. Out-of-range or non-finite values, or an unconnected Mandatory input, invoke the On Error verb.
Calculate distance — The Haversine formula computes the great-circle distance between the input point and the geofence centre.
Compare — If the distance is less than or equal to Radius, Out is true; otherwise false.
Assume the geofence centre is London: Latitude 51.509865, Longitude -0.118092.
Radius: 5.0 km
| Input | Value |
|---|---|
| Latitude | 51.507351 (Trafalgar Square) |
| Longitude | -0.127758 |
Output: true — the point is within 5 km of the centre.
Radius: 5.0 km
| Input | Value |
|---|---|
| Latitude | 51.2588 (Brighton) |
| Longitude | -0.1509 |
Output: false — Brighton is well beyond 5 km from London.
Radius: 5.0 km
| Input | Value |
|---|---|
| Latitude | 91.0 |
| Longitude | 0.0 |
Output: unchanged; the path stops.
GPS Location can hit these errors: an unconnected Mandatory Latitude/Longitude input, a non-numeric value (the Type mask catches most of these earlier), latitude outside [-90, 90], longitude outside [-180, 180], or any non-finite value.
Any of these triggers the On Error verb you picked. See the Error Handling guide for the common On Error model; GPS Location’s options are:
| Verb | What it does |
|---|---|
| Stop this branch (default) | This Node and its dependents stop; Out keeps its value and reads as a failed update. |
| Continue with the last value | Dependents run on the value Out already holds, not stamped as new; it reads as a failed update. |
| Continue with the fallback | Dependents run on Out’s per-output Fallback, stamped as this run’s value; it reads as a failed update. The Editor refuses a Task where the Fallback is unset. |
Out carries the per-output Fallback you set in Settings under the Out port, like any other Output — Nil until you set one, and a Boolean false is the usual choice for a location test.
Gate closure is not an error — a closed Gate stops the Path and consults no verb.
