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Making Usable Data Available and Available Data Usable: The Application of Geospatial Standards in Near Real-Time Sensor Networks. Daniel Getman Aaron Myers Geographic Information Science and Technology Group Oak Ridge National Laboratory April 20, 2007. What is SensorNet.
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Making Usable Data Available and Available Data Usable: The Application of Geospatial Standards in Near Real-Time Sensor Networks Daniel Getman Aaron Myers Geographic Information Science and Technology Group Oak Ridge National Laboratory April 20, 2007
What is SensorNet • Much more than what is presented here • Stand Alone Sensor Networks • Mobile Sensor Systems • Weigh Station Systems • Port Systems • Military Base Systems • Distributed Sensor Networks • Connecting stand alone systems in a larger network • Overarching Concepts • Interoperability/Standards • Real Time Data Distribution and Alerting • Ubiquitous Data Access • Development of Global Scale Sensor Networks
Describing the Stand Alone Systems • Multiple Sensors • Chemical – Radiation – Biological – Weather • Video with real time analysis capabilities • Multiple Viewers • ArcMap • Google Earth • Browser based viewers • Integration with Models • HPAC • Data Distribution Capabilities • Mobile systems communicating with operations centers and other systems
Defining The Goals • Minimum System Goal • Provision of near real-time data within the stand alone system while also providing access to data to external users including Operation Centers and other emergency response personnel • Maximum System Goal • Develop an open standards based system within which a variety of sensors, viewers, and complete stand alone systems can plug-and-play can use and share near real-time sensor data • Stretch Goal • Make the openness of the system transparent to all users
Standards Used in the Stand Alone Systems • Open Geospatial Consortium (OGC) • Sensor Web Enablement (SWE) • Includes Sensor Observation Service (SOS), Sensor Alert Services (SAS), and Sensor Planning Service (SPS) • Web Feature Service (WFS) • Geography Markup Language (GML) • U.S. Department of Homeland Security (DHS) • ANSI N42.42 (Radiation Data Representation) • Organization for the Advancement of Structured Information Standards (OASIS) • Common Alerting Protocol (CAP) • National Institute of Standards and Technology (NIST) • IEEE 1451 (Sensor Plug-n-play) Courtesy: David Resseguie, ORNL
Why Standards are Great • Standards are great once they are adopted • Data sharing is not only easier but can be easily automated • Everything is less expensive…eventually • Creativity is stimulated in application development
Why Standards Can Be Difficult to Use • Querying differences • Data Size Differences • Data Structure Differences Traditional Database Query WFS Database Query
WFS and SQL Queries • Traditional SQL Query SELECT Col1, Att1, Val1 FROM TABLE1 WHERE Val2 = “SomeValue” • WFS Query<wfs:GetFeature service="WFS" version="1.0.0" xmlns:gml="http://www.opengis.net/gml" xmlns:ogc="http://www.opengis.net/ogc" xmlns:snet="http://www.sensornet.gov/snet" xmlns:wfs="http://www.opengis.net/wfs"> <wfs:Query typeName=“snet:Table1"> <ogc:Filter xmlns:ogc="http://www.opengis.net/ogc"> <ogc:PropertyIsLike> <ogc:PropertyName>//snet:Val2</ogc:PropertyName> <ogc:Literal>SomeValue</Literal> <ogc:PropertyIsLike> </ogc:Filter> </wfs:Query> </wfs:GetFeature>
Practical Difficulties • Clients can have conflicting expectations • Things that are difficult with Standards Based Systems • Legacy Software and Data • Few software packages will natively access standards based data sources • Familiar/Robust/Highly Functional Interface • It has to be as good as the proprietary system • Near Real-Time Dynamic Data • Lots of queries, some very specific (alerting) • Database Design Limitations • Designed for support of standard rather than support of user activities • Large Data Capacity can be problematic • Keeping all of the data without impeding system speed • Data Integration • Leveraging of existing proprietary data
The Duct Tape Approach • Implement standards where the technology and client requirements allow • Implement component based solutions that handle the places in the system where standards either do not exist or are not fully implemented • Plan to remove the duct tape when the standards are implemented and adopted
Tale of Two Deployments • JFHQ SNAPS in Washington DC • Mobile SensorNet System (Actually in a trailer) • JOC System designed to receive data from Mobile and Base systems • GPS enabled Radiation, Chemical, Weather, Video • HPAC Integration • SRRPP at the Port of Charleston • Land and Marine based SensorNet Systems • Vehicle and Officer GPS Tracking • GPS enabled Radiation, Video
Lessons Learned with the SMRSS • Intrinsic problems include • Data is duplicated • Two conversion processes to maintain • Performance Issues • Both WFS and ArcSDE are bottlenecks compared to direct database interaction. Together, they can really hinder performance • The conversion to ArcSDE caused a large number of reads on the WFS. This had a negative impact on the overall performance of the system. More reads per second means less writes per second • Inserting data into ArcSDE is significantly slower than inserting data directly into a database • We found that ArcObjects inserts were faster than SDE API inserts • Querying against the data tables directly in Oracle to gather data used in the conversion process, rather than going through SDE, is a good shortcut • Conversion process can be used for other tasking that would otherwise require an additional WFS call • Alerting and interfacing with other systems (cameras for example)
Realistic Idealistic SensorNet System Everyone Gets What They Want Single Conversion Utility No pounding the WFS with SDE Inserts
Evolution of the RISS Times They Are A-Changin'
- Questions and Comments - Daniel Getmangetmandj@ornl.gov865-241-1745