Specifying events OWS-7 Event Architecture Engineering Report

Copyright © 2010 Open Geospatial Consortium, Inc. 105 Table 40: Template for tabular listing of names for an event Event Identifier a Name Label codeSpace a optional Value event identifier-code space optional and value URI defining the codeSpace of the name label – for example http:your- domain.netevents String representing the actual value of the name or label – for example “Result Available” codeSpace X value X codeSpace Y value Y … … a Although some values listed in the column appear to contain spaces, they shall not contain spaces. Table 41: Template for tabular listing of suitable encodings for an event Event Identifier a Encoding Namespace a UML Class XML Element Name a Constraints optional event identifier- code space optional and value identifier of the application schema where the class element is defined – for example “http:www.o pengis.netswe s2.0” Name of the class element that is used to encode the event – for example “SWESEvent” Textual description of further encoding constraints – for example to define required values for encoded properties ”code = CAPABILITIESCHANGE” etc. namespace X class element name X … namespace Y class element name Y … … … … event identifier Z namespace Z class element name Z … a Although some values listed in the column appear to contain spaces, they shall not contain spaces. 106 Copyright © 2010 Open Geospatial Consortium, Inc. 10.2 Specifying event channels For specifying new event channels, the relevant information is: required: o a unique identifier for the channel o a listing of the events that can be published on the channel and the encoding of these events optional: o an indication whether unknown events can be posted on the channel or not default is true Like an event, an event channel is identified by a unique string value. We recommend using a single URL as identifier e.g. http:www.opengis.netows7aimchannelsWeather . Another option is to use a combination of a code space given as URI, e.g. http:www.opengis.netows7aimchannels and a string value e.g. Weather . The following table can be integrated in specifications to define which event is published on a given channel in which encoding. Table 42: Template for defining an event channel Event Channel Identifier a Unknown Events Published Event Identifier Encoding codeSpace optional a value a Namespace a UML Class XML Element Name a Constrai nts option al event channel identifier- -code space optional and value example: http:ww w.opengis. netows7 aimchann elsWeath er false http:www.o pengis.net ows7aime vents Forec ast http:www.e urocontrol.i ntwx1.1 Forecast none http:www.o pengis.net ows7aime vents Obse rvat ion http:www.e urocontrol.i ntwx1.1 Observatio n … … … … … … … … … … … … … … … … … … a Although some values listed in the column appear to contain spaces, they shall not contain spaces. Copyright © 2010 Open Geospatial Consortium, Inc. 107 11 Application of the Event Architecture in OWS-7 This section provides a brief overview of the OWS-7 use cases where Event Architecture aspects played a role.

11.1 Geosynchronization

The Geosynchronization service allows publication of the availability of new data or updates to existing data. The information about these events is encoded and published to interested subscribers. Different event types and channels are defined to support the controlled revision of feature updates and replication of feature stores. A possible use case is to synchronize the feature stores at different government levels from local to national stores – see the following figure. Figure 35: Synchronizing feature data on various government levels – a use case for Geosynchronization More detailed information about Geosynchronization can be found in OGC document 10- 069. 108 Copyright © 2010 Open Geospatial Consortium, Inc.

11.2 Dynamic Sensor Tracking and Notification

The Sensor Fusion Enablement thread in OWS-7 investigated how the tracking of moving sensors and detection of changes in video streams can be realized using OGC standards, especially the SWE standards. One important component of the resulting service architecture is the Tracking and Notification Service. This is a web service that offers publish subscribe functionality. Its purpose is to continuously monitor the stream of GPS position events of a vehicle and notify the client when it detects that the vehicle entered an Area Of Interest AOI. The change detection process offered by a WPS would then be invoked and clients notified of any detected changes – see the following figure. Figure 36: Dynamic sensor tracking and notification – use case of the OWS-7 SFE thread More detailed information about dynamic sensor tracking and notification can be found in OGC document 10-061.

11.3 Aviation

The aviation thread in OWS-7 used Event Service functionality to notify subscribed clients – flight dispatchers and pilots – of events that were of interest to a planned or ongoing flight. Aeronautical events e.g. of runway closures and special use airspace activations as well as weather events e.g. severe thunderstorms that are located within a certain distance of an aircraft’s flight path were detected and delivered to the respective clients. These events were then visualized and appropriate actions taken – for example to