Generation and retrieval of SNAPSHOT time slices

Copyright © 2011 Open Geospatial Consortium, Inc. All Rights Reserved. 21

7.1.2.5 Digital NOTAM generation

CADAS-AIMDB supports the generation of DNOTAM events following the specification given in the document Digital NOTAM Event Specification, Proposed Release, Increment 1. When TEMPDELTA time slices are inserted via the Transaction operation, DNOTAMs with digital encoding are created and sent to interested parties by a Web Service message. In OWS-8 these are event brokers that themselves categorize, forward and distribute events to registered clients on a subscriber-publisher basis. In the current implementation, only a basic support for DNOTAMs is available. No scenario identification or validation of business rules is performed.

7.1.2.6 Metadata support

In OWS-8, support for the storage and retrieval of metadata on time slice level was added to CADAS-AIMDB.

7.1.3 Luciad

Luciad provided an OGC Web Feature Service to retrieve Special Activity Airspace SAA data provided by the FAA. The WFS supports filtering on properties, spatial filtering for instance, to retrieve airspaces that potentially affect a flight route, and basic temporal filtering. One of the challenges with serving the SAA data is the handling of the separate airspace components that are combined using constructive geometry operations, such as unions and subtractions. The Luciad WFS supports the additional processing required for exact spatial queries on such complex airspaces. This allows you to evaluate exactly whether a point lies inside or outside of a particular airspace. The supplied data also contained links between features, for instance from an air traffic control service to the airspace for which it provides a traffic separation service. These links pose additional issues when they are encountered by client applications. This issue is avoided by the WFS by automatically converting all links to local links to features that were included with the response.

7.1.4 WFS Service Capabilities - Summary

A Web Feature Service supports a certain set of functionality, for example operations, operation parameters, feature types, filter operations as well as operands. This section provides a summary of the respective capabilities for each WFS that is introduced in the previous sections. Table 1 – WFS Service and Operation Capabilities Snowflake GO Publisher WFS Comsoft CADAS- aimdb-WFS Luciad WFS Service Version 1.0   Compliancy tested