withinDistance (Function)

Two available sets of parameters:

• First set returns true if the specified coordinates are within a given distance of the geo.json.geometry.fence.
• Second set returns true if the area specified by geo.json.geometry is within a given distance of the geo.json.geometry.fence.

Syntax

<BOOL> geo:withinDistance(<DOUBLE> longitude, <DOUBLE> latitude, <STRING> geo.json.geometry.fence, <DOUBLE> radius)
<BOOL> geo:withinDistance(<STRING> geo.json.geometry, <STRING> geo.json.geometry.fence,  <DOUBLE> radius)

Query Parameters

Name	Description	Possible Data Types	Optional	Dynamic
longitude	Longitude of the geo location.	Double	Yes	Yes
latitude	Latitude of the geo location.	Double	Yes	Yes
geo.json.geometry	String that contains geometry type and coordinates for a GeoJSON geometry.	String	Yes	Yes
geo.json.geometry.fence	String that contains geometry type and coordinates for a GeoJSON geometry fence.	String	No	Yes
radius	The distance parameter.	DOUBLE	No	Yes

Example 1

geo:withinDistance( 0.5 , 0.5, {'type':'Polygon','coordinates':[[[0, 0],[0, 1],[1, 1],[1, 0],[0, 0]]]}, 110574.61087757687)

In this example, the geo:withinDistance() function checks if the given point (0.5, 0.5) is within a certain distance from the specified polygon defined by the coordinates [[[0, 0],[0, 1],[1, 1],[1, 0],[0, 0]]]. The distance specified is 110574.61087757687 meters. As the point lies within the polygon, it is indeed within the given distance, therefore the function returns true.

Example 2

geo:withinDistance( {'type':'Polygon','coordinates':[[[0.5, 0.5],[0.5, 1.5],[1.5, 1.5],[1.5, 0.5],[0.5, 0.5]]]} , {'type':'Polygon','coordinates':[[[0, 0],[0, 1],[1, 1],[1, 0],[0, 0]]]}, 110574.61087757687)

In this example, the geo:withinDistance() function checks if the first polygon, defined by the coordinates [[[0.5, 0.5],[0.5, 1.5],[1.5, 1.5],[1.5, 0.5],[0.5, 0.5]]], is within a certain distance from the second polygon defined by the coordinates [[[0, 0],[0, 1],[1, 1],[1, 0],[0, 0]]]. The distance specified is 110574.61087757687 meters. Given that the two polygons overlap, they are indeed within the specified distance of each other, so the function returns true.

Example 3

CREATE STREAM InputGeoStream (longitude double, latitude double, geoJsonFence string, radius double);
CREATE SINK STREAM OutputGeoStream (withinDistanceStatus bool);

@info(name = 'WithinDistanceStatusCheck')
INSERT INTO OutputGeoStream
SELECT geo:withinDistance(longitude, latitude, geoJsonFence, radius) AS withinDistanceStatus
FROM InputGeoStream;

In this stream worker example, the WithinDistanceStatusCheck query processes events from the InputGeoStream, which includes geographical coordinates (longitude, latitude), a GeoJSON fence (geoJsonFence), and a radius. The query uses the geo:withinDistance(longitude, latitude, geoJsonFence, radius) function to check if the given point is within the specified distance from the GeoJSON fence. The distance status is then sent to the OutputGeoStream for each processed event.