18 Copyright © 2011 Open Geospatial Consortium,
Inc. All Rights Reserved.
1. Simplifying data retrieval requiring multiple queries
Although GO Publisher WFS implements many of the optional query parameters and filter expressions defined in the WFS specification however, it emerged that to
successfully retrieve AIXM 5.1 data based on the scenarios requires the implementation of: i Local resolve and wfs:valueOf and ii join query predicates. Both of these query
parameters enable users to place queries that traverse properties containing xlink references to generate the response. Such queries are important in AIXM 5.1 as the
relationships between features are one-directional so they should remove the requirement for reverse associations. It should also remove the requirement to submit multiple
requests to obtain a result.
2. Retrieving specific timeslices
The WFS specification supports versioning which enable users to retrieve specific versions of a feature from within a data store, however, it does not support the ability to
support the retrieval of specific timeslices from dynamic features. This is currently a serious issue; proposals for the support of timeslice retrieval are being developed in the
WFS Guidance ER.
7.1.2 Comsoft
7.1.2.1 Overview
COMSOFT’s Aeronautical Information Management Database CADAS-AIM
DB
is a fully featured AIXM 5 database. It has been especially developed to natively support all
concepts of AIXM 5. It is designed to serve as a base for integrating AIM products and components such as electronic AIP, Charting, NOTAM Office, or Briefing with a central
Aeronautical Database.
A design principle is the interoperability with other systems. As the database is the core of any integrated AIM solution an open interface that can be used independently from
any platform and programming language is one of the key features. For an optimal support of AIXM 5 CADAS-AIM
DB
provides the CAW-interface. In OWS-7, support for the emerging WFS 2.0 standard was added and further improved in OWS-8.
7.1.2.2 Purpose in OWS-8
In OWS-8, the CADAS-AIM
DB
is used as WFS data store and DNOTAM event source. As a WFS data store, it hosts static BASELINE and PERMDELTA time slices and
dynamic data TEMPDELTA time slices. Time slices can be retrieved from and stored to the WFS. The retrieval operations support complex filters built of logical, spatial,
temporal and comparison operators.
When TEMPDELTA time slices are inserted, corresponding DNOTAM events are created and sent to interested parties by a Web Service message.