1. AIXM 5 UML to XSD

2. Aspects of the AIXM UML Model GML Concepts
Dynamic Features
Object-Property Model
Example Mapping
Aeronautical Information Exchange Model (AIXM) is an XML exchange standard based on a subset of GML.
This presentation follows on from the AIXM UML Modelling Presentation.

3. Abstract Model The building blocks for the AIXM XML Schema
The XSD implements the Abstract Model. For example, each Feature will have a TimeSlice and an Extension.
The model should contain a set of abstract AIXM classes that are used as the building blocks for the AIXM XML Schema. However, for simplicity, these relationships are not shown on any diagram.
The UML below shows how each and every <<feature>> inherits from the abstract AIXMFeature class. The concrete features are described by TimeSlices which are composed of properties. The TimeSlice inherits from the abstract AIXMFeatureTimeSlice class.

4. Nil Reason
Nil Reason – not shown on UML but is in the XSD

5. Aspects of the AIXM UML Model GML Concepts
Dynamic Features
Object-Property Model
Example Mapping
Aeronautical Information Exchange Model (AIXM) is an XML exchange standard based on a subset of GML.

6. Dynamic Feature Change over time Timeslice
Features change over time. This concept is called “dynamic features” and is captured as timeslices in GML. In AIXM all attributes and relationships are said to change over time and therefore are captured in the Feature timeslice object. GML timeslices were extended in AIXM to include interpretation, sequence number, correction number and metadata (compliance with metadata standards).

7. Object Property Model
No GML object may be the immediate child of a GML object - no element may be both a GML object and a GML property
An association between two features (or a feature and an object) is implemented over a property of the feature, e.g.
<AirportHeliport> <!-- feature --> <hasReferencePoint> <!-- property --> <ElevatedPoint> <!-- object -->
This explains some of the complexity of the XSD.

8. Aspects of the AIXM UML Model GML Concepts
Dynamic Features
Object-Property Model
Example Mapping
Example mapping will use the Runway feature. Objects are mapped in a similar manner.

9. Example Mapping (1)
An XML Schema group is generated for each feature containing all of the properties (attributes and relationships) of the feature

10. Example Mapping (2)
For each feature a TimeSlice property is created that contains an array of feature TimeSlice objects

11. Example Mapping (3)
The FeatureTimeSlice object is of type FeatureTimeSliceType

12. Example Mapping (4)
A GML property type containing a FeatureTimeSlice objects is created

13. Example Mapping (5)
Continuing with the object-property model, the Runway feature type is created extending the AbstractAIXMFeatureType with the RunwayTimeSlice object

14. Example Mapping (6)
The Runway feature is then defined by the RunwayType.

15. Example Mapping (7)
When a property of a feature is a relationship, the relationship must be associated to another feature or object. This is done through the creation of the FeaturePropertyType
In AIXM, when the relationship or association points to another feature the feature is referenced using the xlink:href attribute. When the relationship points to an object, the object is included inside the parent
When generating the AIXM schema definition we use xlink:href when the relationship points to a feature.
When the relationship points to an object, we include the object inside the parent. In this example the relationship “isEffective” points to the object Timetable so when creating the TimetablePropertyType the object was included. (Objects can not exist without the parent.)

16. Example Mapping (8)
All Features and Objects can be extended

17. Resources
AIXM UML to XSD Mapping document is online at:
The document included mappings for the enumerations, codelists and objects.

18. Thank you