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Experiences with SWE. Presentation to WGISS28 Pretoria, September 2009. Wyn Cudlip BNSC/GeoSeren. wcudlip@geoseren.com. Background. Project underway to develop prototype system for sensor management using Sensor Web Enablement (SWE) Standards from OGC Making use of
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Experiences with SWE Presentation to WGISS28 Pretoria, September 2009 Wyn Cudlip BNSC/GeoSeren wcudlip@geoseren.com
Background • Project underway to develop prototype system for sensor management using Sensor Web Enablement (SWE) Standards from OGC • Making use of • 52degree North SWE software toolkit • OSCAR SWE software package developed by ComSine (1Spatial) • Monitoring water quality in Dam in the West Country in the UK • In this presentation will concentrate on the issues of: • Definition of a SWE Node • Access control • Accessing sensor information
What is a SWE Node? • A SWE Node is a computing element with an IP address connected to the internet and understands SWE protocols (http) SOS, SAS, SPS, WNS • Could be a desktop PC, Laptop or portable computing device running appropriate software • Internally contains proprietary interface to specific sensor or sensor network • No prescribed method for communicating with sensor. Could use: • RS232; GSM; Radio; Satcom • Therefore, can be varying degrees of complexity within a SWE Node
Roles & Groups for Access Control Problem: ‘Sensors’ assigned to (multiple) groups • Improved access to the sensor services requires control over user capability • Many users might have read access (SOS) but need to restrict the ability to task a sensor (SPS) • Sensors assigned to different 'Groups' • Users are assigned different Roles for different Groups. E.g 'Viewer' or 'Sensor Controller’ • Attaching a new sensor to a group automatically allows controlled access to that sensor Agency 1 Solution Field Trial Agency 2 User 2 Role User 1 Role Agency 1 Viewer Agency 1 Viewer Agency 2 Controller Field Trial
Observation Identification • Problem: When managing multiple sensing platforms, labelling observations in a meaningful way is difficult. • Usually there is a naming hierarchy: • SWE Node1 (e.g. Tamar Lake Services) (with internet address) • SOS Service1: SAS Service1; SPS Service1 (e.g. Weather information) • Observation Offering1 (e.g. Weather at Dam) • Sensor1 (e.g. Vaisala weather station) • Observable Parameter1 (Feature of interest). (e.g. temperature) • Observable Parameter2 (e.g. Precipitation) • Sensor2 (e.g. YSI Sonde) • Observable Parameter 1 (e.g. Temperature) • ...... • Observation Offering2 (e.g. Camera observation at dam) • ........ • SOS Service2 (e.g. Water Quality) • .... • SWE Node2 (e.g. Tamar River Services) • ........ • SWIMA Solution: Concept of ‘Vstation’ or ‘MySensors’ • Observable parameters (from any SWE Node) identified as a user-defined set. • (see user interface slide for clarification)
Conclusion • 52degree North provide useful toolbox to help SWE implementations • But not yet complete, some bugs and limited documentation • Other implementations becoming available • As access to sensor services becomes easier then more effort with security is required. • Prototyping in real-life situations usually reveal additional issues