touches (Function)

Two available sets of parameters:

• First set returns true if the incoming geo.json.geometry event touches the given geo.json.geometryFence.
• Second set returns true if the coordinates touch the given geo.json.geometryFence.

Syntax

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

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

Example 1

geo:touches( 
    {'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':[[[10, 10],[10, 11],[11, 11],[11, 10],[10, 10]]]} 
)

In this example, the geo:touches() function checks if the two given polygons share any boundary points. The first polygon is defined by the coordinates [[0.5, 0.5],[0.5, 1.5],[1.5, 1.5],[1.5, 0.5],[0.5, 0.5]], and the second polygon is defined by the coordinates [[10, 10],[10, 11],[11, 11],[11, 10],[10, 10]]. The function returns false because these two polygons do not share any boundary points - they do not touch each other.

Example 2

geo:touches(10.5, 20.5, {'type':'Polygon','coordinates':[[[0, 0],[0, 1],[1, 1],[1, 0],[0, 0]]]})

This example returns false because the point with coordinates (10.5, 20.5) does not touch the polygon defined by the coordinates [[0, 0],[0, 1],[1, 1],[1, 0],[0, 0]]. In other words, the point does not share any boundary points with the polygon.

Example 3

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

@info(name = 'TouchesStatusCheck')
INSERT INTO OutputGeoStream
SELECT geo:touches(longitude, latitude, geoJsonFence) AS touchesStatus
FROM InputGeoStream;

In this stream worker example, the TouchesStatusCheck query processes events from the InputGeoStream, which includes geographical coordinates (longitude, latitude) and a GeoJSON fence (geoJsonFence). The query uses the geo:touches(longitude, latitude, geoJsonFence) function to check if the given point shares any boundary points with the GeoJSON fence. The touch status is then sent to the OutputGeoStream for each processed event.