GeoConnections

What is Sensor Web Enablement (SWE)?

A framework of two sets of specifications that define the information and service model for:

1. Discovering sensor systems, observations and observation processes;

2. Determining sensor's capabilities and quality of measurements;
3. Accessing sensor parameters that automatically allow software to process and geo-locate observations;
4. Retrieving real-time or time-series observations and coverages in standard encodings;
5. Tasking sensors to acquire observations of interest; and
6. Providing notifications from sensors or sensor services based upon user-specified criteria.

These functions are being enabled through the establishment of several encodings for describing sensors and sensor observations and through the definition of standard interfaces implemented as web services.  Figure 1 illustrates the role of the SWE framework.

Figure 1: Role of SWE

OGC members are specifying interoperability interfaces and metadata encodings that enable real time integration of heterogeneous sensor webs into the information infrastructure. Developers will use these specifications in creating applications, platforms, and products involving Web-connected devices such as flood gauges, air pollution monitors, stress gauges on bridges, mobile heart monitors, Webcams, and robots as well as space and airborne earth imaging devices.

OGC members have developed and tested the following candidate specifications. Others are planned.

1. Observations & Measurements (O&M) - Standard models and XML schema for encoding observations and measurements from a sensor, both archived and real-time.
2. Sensor Model Language (SensorML) - Standard models and XML schema for describing sensors systems and processes; provides information needed for discovery of sensors, location of sensor observations, processing of low-level sensor observations, and listing of taskable properties.
3. Transducer Model Language (TransducerML or TML) - The conceptual model and XML schema for describing transducers and supporting real-time streaming of data to and from sensor systems.
4. Sensor Observations Service (SOS) - Standard web service interface for requesting, filtering, and retrieving observations and sensor system information. This is the intermediary between a client and an observation repository or near real-time sensor channel.
5. Sensor Planning Service (SPS) - Standard web service interface for requesting user-driven acquisitions and observations. This is the intermediary between a client and a sensor collection management environment.
6. Sensor Alert Service (SAS) - Standard web service interface for publishing and subscribing to alerts from sensors.