[AIXM-600] Add slope to RunwayDirection

Description

A new slope property is added to RunwayDirection.

Rationale for change

See https://aixmccb.atlassian.net/browse/AIXM-594

Originally the runway slope was published in AD2.12 of the printed AIP. Over the years it became a common practice to publish runway profile points with elevations on the OC Type A, allowing to determine a detailed runway profile. Adding a slope attribute to the runway direction will allow states to publish the slope in accordance with the data catalogue. The coding guideline, however, should recommend the definition of profile points instead.

Impact assessment

[FWD_1:1] No data mapping is necessary and no data loss occurs when data is exchanged from a system (A) that uses AIXM 5.1.1 for output towards a system (B) that uses AIXM 5.2 for input.

[BWD_MAP_LOSS] Data mapping is possible, but some data would be lost (or converted into Notes) when data is exchanged from a system (B) that uses AIXM 5.2 for output towards a system (A) that uses AIXM 5.1.1 for input.

Change Proposal details

In the UML model:

• Add the attribute slope of type ValSlopeType to the RunwayDirection Definition: “The average slope of the physical runway from approach end to departure end”

The following UML class diagram shows the new attribute. For information, this diagram also shows the RunwayCentrelinePoint class, which may be used for coding in detail the runway centreline elevations profile.

Mapping AIXM 5.1.1 to AIXM 5.2 (forward)

• Not applicable

Mapping AIXM 5.2 to AIXM 5.1.1 (backward)

[MAPC-02] For each RunwayDirection that has the specified slope child element, from the three backward mapping options available, the first two (discard the value or use an extension) are straightforward and do not need any further details. The 3rd option (backward mapping into a Note) is detailed in order to provide a complete description of this case and its conversion option. The following mapping into Note algorithm is proposed:

• Remove the slope element
• Add an annotation.Note associated with the RunwayDirection class having:

• purpose=“OTHER:BACKWARD_MAPPING”
• LinguisticNote.note=”slope: <value of slope>”.

Note: In both model versions, the runway slope could be modeled more precisely using runway centreline (profile) points with their elevation. However, this cannot be used for backward mapping, since the original algorithm to determine the slope is not known. Application of a different algorithm (if there are more than two points in the profile) could result in another slope than the originally published one.

Mapping example

(Note: for mapping test data see: https://github.com/aixm/mapping_52_511/tree/master/AIXM-600) 

AIXM Input	AIXM Output