Data coding guidelines

Why necessary

The AIXM logical data model uses meaningful names for classes, attributes and associations and it provides definitions for each class, property and data type. Aeronautical information domain experts should be able to "decode" most of the model by recognising the information items that are in the scope of AIXM. However, not all AIXM users are likely to have a deep knowledge of the aeronautical information domain and certain parts of the model (such as instrument approach procedures, services, etc.) are by their nature relatively complex. In addition, AIXM version 5 comes with a complex temporality concept and it uses GML, which is general-purpose geographical information coding standard.

These aspects increase the risk that various implementations come with their own local interpretation of the model, with negative impact on interoperability. Therefore, there is a need for globally agreed coding guidelines. This should be supported as much as possible by precise business rules, which can be used to actually verify if an AIXM data set complies with the common coding guidelines.

This page provides information about coding guidelines dedicated to the latest AIXM version (5.1/5.1.1). For the AIXM 4.5 version, further information (AICM 4.5 Manual, AIXM 4.5 Primer, etc.) is available in the AIXM 4.5 Specification section.

"Technical" coding guidelines

The AIXM 5.1/5.1.1 Specifications include a series of "technical" coding guidelines, that are generally applicable, regardless of the kind of data (routes, runways, navaids, etc.) that is encoded. This includes the following:

AIXM Temporality Concept (version 1.0)

AIXM feature Identification and Reference (version 1.0)

Guidance and Profile of GML for use with Aviation Data (OGC 12-028r1)

Through the Aviation Domain Working group of OGC, a series of other guidelines documents have been developed and published as OGC Discussion Papers:

Requirements for Aviation Metadata (OGC 10-195)

Guidance on Aviation Metadata (OGC 10-196r1)

Web Feature Service (WFS) Temporality Extension (12-027r3)

"Content specific" coding guidelines

There are two forms in which coding guidelines for specific aeronautical data items can be provided:

  • mapping documents, which relate the AIXM model elements to aeronautical information publication/provision standards and specifications, such as the AIP content and structure (ICAO Annex 15, Appendix 1)
  • coding documents dedicated to a specific topic, such as procedures, airspace, etc.

The following mapping documents exist to date:

AIP - AIXM Mapping, working draft 

Airport Mapping Requirements (as defined in the EUROCAE/RTCA documents ED-99A/DO-272A), proposed release

AIXM 4.5 to AIXM 5.1 mapping, version 1.1 (an updated version is in preparation)

Topic coding guidelines

A dedicated Focus Group was launched in May 2016 by Eurocontrol. The objective of this group is to develop globally applicable coding guidelines for the following topics:

  • Routes
  • Airspace
  • SID/STAR/Approach
  • Airport infrastructure
  • Airport usage restrictions
  • Navaids and points (including VFR reporting points)
  • Units/Services
  • Obstacles

For this purpose, the group will work in cooperation with the global AIXM community, in particular with the AIXM Change Control Board members. The finalisation of the Digital NOTAM Event Specification 2.0 and the development of further Digital  NOTAM coding scenarios is also in the terms of reference of the group.

Information about the progress made by this group will be provided regularly and the draft coding guidelines will be provided for public review, through the AIXM Forum.