stationary (Stream Processor)
Determines if the specified object or location becomes stationary within a specified radius. Returns false when the object moves out of the specified radius.
This function will return true when the object (defined in terms of longitude and latitude) becomes stationary within the specified radius. Returns false when the object moves out of the specified radius.
Syntax
<BOOL> geo:stationary(<STRING> id, <DOUBLE> longitude, <DOUBLE> latitude, <STRING> geo.json.geometry.fence, <DOUBLE> radius)
Query Parameters
| Name | Description | Possible Data Types | Optional | Dynamic |
|---|---|---|---|---|
| id | ID of the specified object. | STRING | No | No |
| longitude | Longitude value of the geo location. | DOUBLE | No | No |
| latitude | Latitude value of the geo location. | DOUBLE | No | No |
| geo.json.geometry.fence | String that contains geometry type and coordinates for a GeoJSON geometry fence. | STRING | No | No |
| radius | Proximity distance (radial). | DOUBLE | No | No |
Example 1
geo:stationary('km-4354', 0, 0, 110574.61087757687)
In this example, the geo:stationary() function checks if the given geofence with ID km-4354 is considered stationary within the given radius of 110574.61087757687 from the reference point (0, 0). The function returns true if the geofence is stationary.
Example 2
CREATE STREAM InputGeoStream (geofenceId string, longitude double, latitude double, radius double);
CREATE SINK STREAM OutputGeoStream (stationaryStatus bool);
@info(name = 'StationaryStatusCheck')
INSERT INTO OutputGeoStream
SELECT geofenceId AS id, stationary
FROM InputGeoStream#geo:stationary(geofenceId, longitude, latitude, radius);
In this example, a stream named InputGeoStream is created to provide input to the query, and OutputGeoStream is created to collect the output. The StationaryStatusCheck query processes events from InputGeoStream, which consists of a geofence ID, geographical coordinates (longitude, latitude), and a radius. It uses the geo:stationary(geofenceId, longitude, latitude, radius) function in the FROM clause of the query to check if each geofence is stationary within its specified radius. The result, along with the geofence ID, is inserted into OutputGeoStream.