Filtering by Feature of Interest
A Feature of Interest (FOI) is the feature that a sensor is observing at a given instant. It can refer to an actual object, or something more abstract like an area, a given acquisition run, etc.
OpenSensorHub's SOS implementation supports filtering observations by specifying the ID of a feature of interest. This is what is used to obtain observations from a single node in a large sensor network for instance, or to retrieve observations of a particular object by a mobile sensor.
Below are example HTTP GET requests for filtering by FOI identifier.
GetResult Example
The table below lists parameter of a GetResult request used to retrieve location data from a given time period only for emergency vehicle with ID FE4:
| Parameter | Value |
|---|---|
| request | GetResult |
| offering | urn:mysos:avl |
| observedProperty | http://www.opengis.net/def/property/OGC/0/SensorLocation |
| featureOfInterest | urn:osh:sensor:avl:911:fleet:FE4 |
| temporalFilter | phenomenonTime,2014-03-29T06:16:12Z/2014-03-29T14:26:12Z |
On Demo Server:
GetObservation Example
The table below lists parameter of a GetObservation request used to retrieve location data from a given time period only for the same emergency vehicle with ID FE4:
| Parameter | Value |
|---|---|
| request | GetObservation |
| offering | urn:mysos:avl |
| observedProperty | http://www.opengis.net/def/property/OGC/0/SensorLocation |
| featureOfInterest | urn:osh:sensor:avl:911:fleet:FE4 |
| temporalFilter | phenomenonTime,2014-03-29T06:16:12Z/2014-03-29T06:26:12Z |
On Demo Server:
Notice that in this case we requested much less data because the response is much more verbose.
GetFeatureOfInterest Example
In order to know which ID to use, one needs to know the list of all FOIs observed by a particular sensor. This can be done by issuing a GetFeatureOfInterest request such as below: