Geo Extension

This extension provides geo data related functionality such as checking whether a given geo coordinate is within a predefined geo-fence, etc. Following are the functions of the Geo extension.

Intersects function

Syntax	`<bool> geo:intersects (<string> geoJSONGeometry , <string> geoJSONGeometryFence )`
Extension Type	Function
Description	Returns `true` if the `geoJSONGeometry` incoming event intersects the given string (i.e., `geoJSONGeometryFence`). Returns `false` otherwise.
Example	`intersects( {'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]]]} ),` returns `true` because `geoJSONGeometry` intersects `geoJSONGeometryFence`.

Syntax	`<bool> geo:intersects (<double> longitude , <double> latitude , <string> geoJSONGeometryFence )`
Extension Type	Function
Description	Returns `true` if the location specified in terms of longitude and latitude intersects the given `geoJSONGeometryFence`. Returns `false` otherwise.
Example	`intersects(0.5. 0.5 , {'type':'Polygon','coordinates':[[[0, 0],[0, 1],[1, 1],[1, 0],[0, 0]]]}),` returns `true` because the location specified in terms of longitude and latitude intersects `geoJSONGeometryFence`.

Within function

Syntax	`<bool> geo:within (<double> longitude , <double> latitude, <string> geoJSONGeometryFence )`
Extension Type	Function
Description	Returns `true` if the location specified in terms of longitude and latitude is within the `geoJSONGeometryFence`.
Examples	`within(0.5, 0.5, {'type':'Polygon','coordinates':[[[0,0],[0,2],[1,2],[1,0],[0,0]]]} )` returns `true`. `within(2, 2, {'type':'Polygon','coordinates':[[[0,0],[0,2],[1,2],[1,0],[0,0]]]} )` returns `false`.

Syntax	`<bool> geo:within (<string> geoJSONGeometry , <string> geoJSONGeometryFence )`
Extension Type	Function
Description	Returns true if the `geoJSONGeometry` is within the `geoJSONGeometryFence`. Returns `false` otherwise.
Example	`within( {'type': 'Circle', 'radius': 110575, 'coordinates':[1.5, 1.5]} , {'type':'Polygon','coordinates':[[[0,0],[0,4],[3,4],[3,0],[0,0]]]} )` returns `true`. `within( {'type': 'Circle', 'radius': 110575, 'coordinates':[0.5, 1.5]} , {'type':'Polygon','coordinates':[[[0,0],[0,4],[3,4],[3,0],[0,0]]]} )` returns `false`.

Within Distance function

Syntax	`<bool> geo:withindistance (<double> longitude , <double> latitude, <string> geoJSONGeometryFence )`
Extension Type	Function
Description	Returns `true` if the location specified in terms of longitude and latitude is within distance of the `geoJSONGeometryFence`. Returns `false` otherwise.
Example	`withindistance( 0.5 , 0.5, {'type':'Polygon','coordinates':[[[0, 0],[0, 1],[1, 1],[1, 0],[0, 0]]]}, 110574.61087757687)` returns `true` because the location specified in terms of longitude and latitude is within the distance of the `geoJSONGeometryFence`.

Syntax	`<bool> geo:withindistance (<string> geoJSONGeometry , <string> geoJSONGeometryFence , <double> distance )`
Extension Type	Function
Description	Returns `true` if the area given by `geoJSONGeometry` is within distance of the `geoJSONGeometryFence`.
Example	`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)` returns `true` because `geoJSONGeometry` is within the distance of `geoJSONGeometryFence`.

Crosses function

Syntax	`<bool> geo:crosses (<string> id , <double> longitude, <double> latitude , <string> geoJSONGeometryFence )`
Extension Type	Function
Description	Returns `true` when the the specified object of which the location is specified in terms of `longitude` and `latitude` crosses the geographic location specified in `geoJSONGeometryFence`. Returns `false` when the object crosses out of the location specified in `geoJSONGeometryFence`.
Example	`crosses(km-4354, -0.5, 0.5, {'type':'Polygon','coordinates':[[[0, 0],[2, 0],[2, 1],[0, 1],[0, 0]]]} )` returns `true`. `km-4354, 1.5, 0.5, {'type':'Polygon','coordinates':[[[0, 0],[2, 0],[2, 1],[0, 1],[0, 0]]]} )` returns `true`.

Syntax	`<bool> geo:crosses (<string> id , <string> geoJSONGeometry , <string> geoJSONGeometryFence )`
Extension Type	StreamProcessor
Description	Returns true when the object (i.e. `geoJSONGeometry`) crosses the specified geographic location (i.e. `geoJSONGeometryFence`). Returns `false` when the object crosses out of `geoJSONGeometryFence`.

Stationary function

Syntax	`<bool> geo:stationary (<string> id , <double> longitude, <double> latitude , <string> geoJSONGeometryFence , <double> radius )`
Extension Type	StreamProcessor
Description	Returns `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.
Example	`stationary(km-4354,0,0, 110574.61087757687)` returns `true`. `stationary(km-4354,1,1, 110574.61087757687)` returns `true.` `stationary(km-4354,1,1.5, 110574.61087757687)` returns `true`.

Syntax	`<bool> geo:stationary (<string> id , <string> geoJSONGeometry , <string> geoJSONGeometryFence , <double> radius )`
Extension Type	StreamProcessor
Description	Returns `true` when the object (i.e. `geoJSONGeometry`) becomes stationary within the specified `radius``.` Returns `false` when the objects moves out of the specified radius.

Proximity function

Syntax	`<bool,string> geo:proximity (<string> id , <double> longitude, <double> latitude , <string> geoJSONGeometryFence , <double> radius )`
Extension Type	StreamProcessor
Description	Returns `true` when two objects (specified in terms of `longitude` and `latitude)` are within the specified `radius` to another object. Returns `false` when the specified object moves out of the specified `radius`. The `proximityWith` optional attribute indicates the ID of the object that the object specified is in close proximity with. `proximityID` is a unique ID for the two objects in close proximity.
Example	The following return `true` with `id 3`. `proximity(1, 0, 0, 110574.61087757687)` `proximity(2, 1, 1, 110574.61087757687)` `proximity(3, 2, 2, 110574.61087757687)` `proximity(1, 1.5, 1.5, 110574.61087757687)`

Syntax	`<bool> proximity (<string> id , <string> geoJSONGeometry , <string> geoJSONGeometryFence , <double> radius )`
Extension Type	StreamProcessor
Description	Returns `true` when an object (i.e. `geoJSONGeometry`) is within the specified `radius` from another object. Returns `false` when one or both objects move away from each other and are no longer within the specified `radiu`s of each other. The `proximityWith` optional attribute indicates the ID of the object that the object specified is in close proximity with. `proximityID` is a unique ID for the two objects in close proximity.

Geo Coordinates function

Syntax	`<double, double, string> geocode (<string> location` `)`
Extension Type	StreamProcessor
Description	Transforms a location to its geo-coordinates ( `longitude` and `latitude` ) and formatted address.
Example	`geocode(duplication rd)` returns the following data with adherring latitude, longitude, and `formattedAddress` attribute names respectively. `6.8995244d, 79.8556202d, "R A De Mel Mawatha, Colombo, Sri Lanka"`

Geo Distance function

Syntax	`<double> distance (<double> latitude1, <double> longitude1, <double> latitude2, <double> longitude2)`
Extension Type	Function
Description	Gives distance between two geo locations in meters.
Example	distance(latitude, longitude, prevLatitude, prevLongitude) returns 2322119.848252557