Requirement
Title | Need for information definitions |
Identifier | SWIM-INFO-001 |
Requirement | Exchanged information shall be documented in an information definition. |
Rationale | The requirement for information definitions is essential in order to facilitate semantic interoperability. Without information definitions, there are no resources to allow the meaning of the information to be clearly defined, understood and harmonised between stakeholders. |
Verification | Completeness |
Examples/Notes | Example: Standardised information exchange models such as the Aeronautical Information Exchange Model (AIXM) [RD10], the Flight Information Exchange Model (FIXM) [RD 11], the Weather Information Exchange Model (WXXM) [RD 13] and the ICAO Meteorological Information Exchange Model (IWXXM) [RD 14]. Example: Descriptions of information exchanged by services. Example: Data catalogues used to list details on the exchanged information. Example: Information exchanges captured as part of a business process model. |
Level of Implementation | Mandatory |
Guidance
The specification gives examples of types of information definitions:
- standardised information exchange models
- descriptions of information exchanged by services
- data catalogues
- information exchanges captured as part of a business process model
The following section gives an overview of these.
Standardised information exchange models
Standardised information exchange models include:
- Aeronautical Information Exchange Model (AIXM)
- Flight Information Exchange Model (FIXM)
- Weather Information Exchange Model (WXXM)
- ICAO Meteorological Information Exchange Model (IWXXM)
- Aerodrome Mapping Exchange Model (AMXM)
They are agreed and published by a particular community of interest. There may be multiple versions of an exchange model e.g. IWXXM 1.1 was used by the SESAR programme but a v2.1 is now available and v3 is open for testing.
The examples above relate to three ICAO business domains. However, other exchange models exist.
A service description may refer to one of these exchange models in order to define its payload.
The figure below provides an extract of the AMXM XML schema. It details "element name", "documentation" and "type" information.
Description of information exchange by services
Services are used to exchange information. Often, the service makes use of a standardised information exchange model as the format for the information exchange. However, other services will develop a more particular payload model. This can be done in the Unified Modeling Language (UML) as given in the figure below.
The figure is taken from a service description for a service exchanging METAR information. It shows the names and definitions of the "EntityItems" that will form the exchanged information.
Data catalogues
Data catalogues are used to list details on the exchanged information. They are often used as a way of agreeing the information that is to be captured and exchanged as part of a publication process. The figure below is taken from the ICAO PANS-AIM Data Catalogue. It is in tabular format and details "subjects", "properties", "types" and their "descriptions". A data catalogue can contain many more items such as requirements on the accuracy of the data to be collected.
Information exchanges captured as part of a business process model
Business process modelling is a key art the service oriented approach. It is used to identify information exchange requirements, including the names and definitions of the elements being exchanged throughout the process.
Verification Support
Completeness
Check that:
- There is an information definition.
- The information definition covers all of the information that is exchanged between the actors.
Notes:
- The information definition can be a standalone document or embedded into another document such as a service description
- The information definition can be made up of a set of documents. This is common practice when designing XML schemas.
Examples
Example information definitions are:
- Aeronautical Information Exchange Model (AIXM)
- EUROCAE ED-252 - this contains a chapter defining the information. It also includes a AIRM conformance statement.
- Flight Information Exchange Model (FIXM)
- Aerodrome Mapping Exchange Model (AMXM)
- ICAO Meteorological Information Exchange Model (IXWWM)