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.

Digital Data Sets (ICAO Annex 15)

A revised Annex 15 and PANS-AIM document are in the final Proposal for Amendment (PfA) adoption process by ICAO. These are expected to become applicable in November 2018. Under the revised ICAO Standards and Recommended Practices (SARPS), the Aeronautical Information Services (AIS) of the ICAO Member States will have to provide digital data organised in the form of the following data sets:

  • AIP Data Set - containing the core "en-route" data (points, navaids, routes, airspace) and also selected airport and runway data
  • Obstacle Data Sets - containing data about obstacles located at or in the vicinity of the aerodromes or within the State territory
  • Instrument Flight Procedures Data Sets - containing data about IFR departure, arrival and approach procedures
  • Airport Mapping Data Sets - containing the digital encoding of the aerodrome layout

Detailed coding guidelines for provision of such data sets in AIXM format are being developed, with priority for the AIP Data Set. 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 these data sets. The coding guidelines that reach 'Proposed' status are provided for public review and further collaborative maintenance through the following pages:

         Coding guidelines for the ICAO Data Sets

"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)

Mappings

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)