Airspace boundaries may be based on national borders or on other geographical features.
The GeoBorder class is used for a physical or political border. In general, it will be the border between two countries or states but could also be a coastline, the description of the bank of an important river, or any other geographical shape which can be named and used to describe the border of an airspace. If two countries/states have more than one common border, each one will be an occurrence of this entity.
A particularity of this situation is that official definitions of the airspace, as provided in the Aeronautical Information Publication (AIP) or in NOTAM messages, do not include the actual geometry of the referenced geographical border. It is left for the end users to derive the actual geometry of the airspace by using a source of geographical border data.
The UML model of AIXM shows a “dependency” association between Surface and GeoBorder to cater for such situations.
The encoding is possible in two ways: either with a simple annotation (and copy of all necessary points) or by reference.
For the detailed AIXM/GML encoding, see the document Guidance and Profile of GML for use with Aviation Data.
Open Question Geoboder
Is there a common set (AIXM 5.1) of geoborders to be used?
Coding Examples
More examples TBD in the scope of the DONLON AIXM AIP data set.