[AIXM-433] Route availability

Description

The possibility to specify the availability of a complete Route is introduced in the model, as a complement to the existing possibility to specify the availability of each individual RouteSegment.

Rationale for change

See https://aixmccb.atlassian.net/browse/AIXM-271 

There are frequent situations where all segments of a route published by an ANSP have the same conditions of usage (availability).

The current model does not support the coding of the availability for a whole route, only at the level of each RouteSegment.  This requires an unnecessary duplication of the data from the ANSP point of view (ICAO AIP Dataset). Therefore, a new association is proposed to be introduced in the model allowing to indicate that RouteAvailability is applicable directly to a Route.

Reminder about “Route direction” information: A Route is composed of several RouteSegments, each one described as “starting” from a SignificantPoint and “ending” at another SignificantPoint.  This gives implicitly a “direction” to the whole route, even if the RouteSegments are communicated in random order, and assuming they describe the complete route part published by the ANSP: the order of the segments can be resolved automatically and as a consequence, the Route direction can be deduced from a “global” starting point to a “global” ending point.

Impact assessment

[FWD_MAP_1:1] Data mapping is possible 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.

Mapping example

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

AIXM 5.2	AIXM 5.1(.1)