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Copyright © 2013 Open Geospatial Consortium.
Robin Houtmeyers Luciad
Matthes Reike 52
North IfGI Claude Speed
SpeedSquared Timo Thomas
COMSOFT Debbie Wilson
Snowflake Software Stuart Wilson
Harris
1.3 Revision history
Date Release
Editor Primary clauses
modified Description
122201 2
0.1 Speed
All Incorporation of component
descriptions and incorporated ERs
124201 2
0.2 Speed
Executive Summary
Incorporation of an Executive Summary and minor edits
122120 12
1.0 Speed
All Final edit
1.4 Future work
Future work to advance the state of OGC standards, their implementation, and interoperability is addressed in this section.
1.4.1 Spatial Filtering of Non-Spatial Features
To enable spatial filtering of AIXM features that do not contain a spatial extent, rules for computing the geometry of such features based upon their constituent parts or that of
other AIXM types that have a relationship to this feature need to be developed. Within former test beds the so-called “Reverse Associations” had been introduced which provide
reverse links to associated features e.g. reverse associations on a Runway referring to its RunwayElements. But evaluation of that approach revealed that the management of such
reverse associations in the AIXM Temporality model is very complex, and the increase in complexity outweighs the benefits. An alternative approach needs to be developed. Since
most AIXM features define multiple representations of a geometry e.g. gml:boundedBy and aixm:ElevatedPoint, future work is proposed to integrate an additional parameter
Copyright © 2013 Open Geospatial Consortium.
9 into the XPath function to define the use case interpretation. This will enable a client to
retrieve different representations for specific tasks. When subscribing for an update interval, client software should be able to define if it is
interested in receiving all messages or only the latest event for the specified time window. The capability of a service to detect different features e.g. two different
Airports within a time window should be specified in the service capabilities and is proposed for future work.
1.4.2 Geometry Processing via Web Processing Service
A WPS geometry retrieval profile can be used to resolve the geometry from an AIXM feature. One specialty of AIXM is that airspaces contain surfaces AirspaceVolumes that
can be formed using geometric operations difference, union, intersection. The WPS server is able to return a set of disjoint GML surfaces that represent the original airspace.
Additionally, airspaces contain altitude data. This is currently not modeled by GML. Proposed future work includes:
Altitude modeling – Proposed future work is to create a custom GML schema that explicitly models the altitude to enable WPS profiles to integrate altitude
calculations into geometry intersection calculations. 2.5D and 3D calculations – Current implementations of the WPS only support the
horizontal extent of AIXM features. One future work item should focus on the integration of the vertical extent to determine whether a general approach for
transforming AIXM 2.5D geometries into GML 3D geometries should be developed.
Additional WPS Profiles – Proposed future work includes development of additional profiles calculate actual altitudes e.g. based on barometric pressure,
DEMs, calculate the containing circle for an Airspace border used for a Digital NOTAM’s Q line, and metadataprovenance resolution.
1.5 Forward
