SensorWeb-Based Prototype for Air Quality Reporting Systems
by Katharina Schleidt and Denis Havlik
Two European research projects, SANY (Sensors Anywhere) and the Austrian INSPIRE CAFE prototype are currently testing the usability of the Open Geospatial Consortium (OGC) Sensor Web Enablement (SWE) suite for CAFE (Clean Air For Europe) and INSPIRE (Infrastructure for Spatial Information in the European Community), by developing a prototype air quality reporting system in accordance with the CAFE directive. Unlike the Web Feature Service, which excels at geographic features, the SWE services and encodings help to model the world from a sensor-centric view, with each observed value being associated with a geographic and temporal position, as well as the unit of measurement, data quality value, and process description.
The INSPIRE directive requires exchange of geospatial data relevant to the environment between public authorities, as well as provision to the research community and to the general public, according to international standards within the next decade. In addition, the Shared Environmental Information System (SEIS) foresees the acquisition and integration of environmental data from distributed sources across Europe for reporting and policy purposes as well as for provision of the information to the public.
Four INSPIRE CAFE prototype projects contracted by Joint Research Center are currently testing possible technical solutions for open standards-based INSPIRE networks suitable for air quality reporting in accordance with the CAFE directive (Clean Air For Europe) in Austria, Poland, Slovakia and the United Kingdom.
CAFE will report annually on the following:
- air quality monitoring zones
- air quality monitoring stations
- validated air quality monitoring data
- threshold exceedances for zones and stations.
In addition, the CAFE directive requires access to the near real time air quality data for general public.
To date, INSPIRE has been driven by the Spatial Data Infrastructure community, relying on traditional OGC Web Feature Service (WFS) services for data provision. Based on an analysis of the requirements of the CAFE directive, the Austrian development team realized that a much stronger focus on the measurements obtained at the monitoring sites would be required than can be served by WSF-based solutions.
In the meantime, the SANY Sensor Anywhere FP6 Integrated Project published the 'Sensor Service Architecture' (SensorSA) specifications. SensorSA advocates the use of the OGC Sensor Web Enablement (SWE) suite for accessing sensors and similar data sources. Unlike other OGC standards, which focus on the spatial aspects of the data, the SWE suite has been designed specifically to interact with sensor networks and allows explicit description and efficient handling of the sensor-related data, metadata and operations.
In addition, SANY developed a number of services for processing and visualization of sensor data, including the 'Cascading SOS' service developed by Austrian Institute of Technology. Cascading SOS can extract the information from available SOS services and produce various indicators, including those required for CAFE reporting, on the fly. Finally, the SANY SP4 air quality demonstrator has already integrated some of the Austrian air quality data in a SensorSA/SWE-compliant network.
This led to the idea of basing the Austrian INSPIRE CAFE prototype on SANY technology. On the SANY side, the air quality use cases, data models and functionality were extended based on the INSPIRE-CAFE requirements. The Umweltbundesamt Austria, which is participating in both projects, provided the concrete requirements for the air quality reporting in accordance with the CAFE directive. These include metadata and data according to the INSPIRE directive, as well as transformed and aggregated data as required by the CAFE directive.
Figure 2: SANY air quality pilot (Linz) use cases and data provision services.
Preliminary results of this work, which will be presented at the final SANY event, confirmed the superiority of OGC SWE-based solutions as compared to classical WFS services, not only for INSPIRE/CAFE affine modelling of the immission and emission sensor data but also for the results of the data fusion, modelling and reporting services ('soft sensors'). In addition, the INSPIRE-compliant version of the SANY catalogue service illustrates that the INSPIRE-relevant meta-information can be harvested from SWE services.
All parties interested in the use of SensorSA and OGC SWE in the context of CAFE and INSPIRE are invited to join the final SANY event and SP4 demonstration on November 19th in Linz. Participation in this event is free of charge, but the registration is required. Instructions for registration are available on the SANY Web site.
OGC SWE: http://www.opengeospatial.org/projects/groups/sensorweb
SANY IP: http://sany-ip.eu
Umweltbundesamt GmbH (Governmental Environmental Agency), Austria
Tel: +43-(0)1-313 04/5363
Austrian Institute of Technology, Safety and Security Division (AARIT)
Tel: +43 50550 3157