ID: | AIXM-584 |
target version: | AIXM 5.2 |
version: | 1.0 |
last updated: | 23 NOV 2022 |
status: | APPROVED |
Description
The SafeAltitudeArea and SafeAltitudeAreaSector classes are renamed MinimumAltitudeArea and MinimumAltitudeAreaSector respectively. Additional attributes and associations are added so that these classes also support the coding of minimum vectoring altitudes, area minimum altitudes and minimum en-route altitudes. The AMA value for Airspace type is removed.
Rationale for change
See https://aixmccb.atlassian.net/browse/AIXM-128
In the current model there is no dedicated class to model the minimum altitudes in an area, such as:
- minimum radar vectoring altitudes around aerodromes (see https://skybrary.aero/articles/minimum-vectoring-altitude-mva);
- area minimum altitudes published on en-route charts in 1x1 degree grids;
- minimum enroute altitudes published in the context of free route airspace.
The Airspace class can be used to a certain extent for coding such data, but it is missing the possibility to indicate the meaning of the altitude (such as “minimum vectoring altitude”). It is also missing the possibility to indicate that such an area is designed in a circular sector shape. Initially, a dedicated class with more specific properties was proposed (see AIXM-562 Change Proposal). However, the resulting model was very similar to the existing SafeAltitudeArea and SafeAltitudeAreaSector model. Therefore, a simplified approach is proposed, which consists in the renaming of the existing classes and the addition of the necessary attributes and coded values so that these classes also support MVA, AMA and MEA values:
- an type attribute that identifies the kind of minimum altitude (MSA, ESA, AMA, MVA, MEA)
- dedicated attributes for altitude and corrected altitude below the low temperature threshold
- an association between the area and the Airspace (typically an FIR) for which the minimum altitudes are defined.
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.
Change Proposal details
In the UML model:
- Rename the class SafeAltitudeArea into MinimumAltitudeArea and modify it as follows:
- change definition into “A specified area within which a set of minimum altitudes is prescribed for specific flight operations, such as instrument approach, radar vectoring, enroute navigation, etc.”
- rename the attribute safeAreaType into type = “The type of flight operations to which the minimum altitude specified for the area is applicable”;
- add a new attribute lowestTemperature, definition = “The seasonal or annual minimum temperature considered for altitude correction at cold temperatures, if applicable”, type ValTemperatureType;
- add an association MinimumAltitudeArea isDefinedWithin Airspace with:
- Airspace role name “concernedAirspace” (definition = ‘The ATS airspace within which the flight operations associated with the minimum altitude take place”), multiplicity 0…*, navigable;
- MinimumAltitudeArea multiplicity 0…*, non-navigable;
- Rename the class SafeAltitudeAreaSecror into MinimumAltitudeAreaSector and modify it as follows:
- change definition into “An area with a specified geometry and minimum altitude values”;
- add a new name attribute, definition = “A pronounceable name that is used to identify the minimum altitude area sector” , type TextNameType
- add a new altitude attribute, definition = “The value of the minimum altitude in the area”, type ValDistanceVerticalType;
- add a new altitudeLowTemperature attribute, definition = “A second value of the minimum altitude in the area, used below the minimum temperature”, type ValDistanceVerticalType;
- Rename the CodeSafeAltitudeBaseType into CodeAreaAltitudeBaseType and modify it as follows:
- definition = “The coded identifier of a type of minimum altitude in relation with a specific category of flight operations to which it applies”;
- add new allowable values:
- AMA_1 = “Area Minimum Altitude with 1 degree gridded sectors”
- AMA_05 = “Area Minimum Altitude with 0.5 degree gridded sectors”
- MVA = “Minimum Vectoring Altitude”
- MEA = “Minimum En-route Altitude ”
- Rename the CodeSafeAltitudeBaseType into CodeAreaAltitudeType
- In the CodeAirspaceBaseType class
- delete the value AMA
The following UML class diagram indicates the modified classes and the new or changed attributes and data types:
Mapping AIXM 5.1.1 to AIXM 5.2 (forward)
The following algorithm shall be applied:
- [MAPC-01] For each Airspace that has a child type element equal-to ‘AMA’:
- replace the value “AMA” with ‘OTHER:AMA”
Note: This simplified mapping takes into consideration two aspects:
- it is unlikely that the current AMA value for Airspace type was actually used in practice
- if AMA was used as Airspace type, an automatic mapping of AirspaceVolumes into the new MinimumAreaSector would be in general quite complicated. The safest option is to re-code the data using the new model. However, if a regular grid of 1 x 1 degree or 0.5 x 0.5 degree rectangles are used for the AMA, an automatic mapping is possible and could be decided in an implementation.
Mapping AIXM 5.2 to AIXM 5.1.1 (backward)
The following algorithm shall be applied:
- For each MinimumAltitudeArea
- [MAPC-00] rename the element SafeAltitudeArea
- [MAPC-01] if has one of the following values, change its value as indicated:
- AMA_1 into OTHER:AMA
- AMA_05 into OTHER:AMA
- MVA into OTHER:MVA
- MEA into OTHER:MEA
- OTHER into OTHER
- [MAPC-07] if there exists a lowestTemperature child element, from the three backward mapping options discussed for this case, 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 lowestTemperature element
- Add an annotation.Note associated with the owner class having
- purpose=“OTHER:BACKWARD_MAPPING”;
- LinguisticNote.note=”lowestTemperature: <lowestTemperature> <uom>
- [MAPC-07] if there exists a concernedAirspace child element, from the three backward mapping options discussed for this case, 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 concernedAirspace element
- Add an annotation.Note associated with the owner class having
- purpose=“OTHER:BACKWARD_MAPPING”;
- LinguisticNote.note=”concernedAirspace: <concernedAirspace.xlink:href>;
- If there exist MinimumAltitudeSector child elements:
- [MAPC-00] rename each MinimumAltitudeSector child elements into SafeAltitudeAreaSector and:
- [MAPC-07] if there exists a name child element, from the three backward mapping options discussed for this case, 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 name element
- Add an annotation.Note associated with the owner class having
- purpose=“OTHER:BACKWARD_MAPPING”;
- LinguisticNote.note=”name: <name>
- [MAPC-07] if there exists an altitude child element, from the three backward mapping options discussed for this case, 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 altitude element
- Add an annotation.Note associated with the owner class having
- purpose=“OTHER:BACKWARD_MAPPING”;
- LinguisticNote.note=”altitude: <altitude> <uom>
- [MAPC-07] if there exists an altitudeLowTemperature child element, from the three backward mapping options discussed for this case, 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 altitudeLowTemperature element
- Add an annotation.Note associated with the owner class having
- purpose=“OTHER:BACKWARD_MAPPING”;
- LinguisticNote.note=”altitude: <altitudeLowTemperature> <uom>
- [MAPC-00] rename each MinimumAltitudeSector child elements into SafeAltitudeAreaSector and:
- If there exist MinimumAltitudeSector child elements:
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) |
|---|---|
... | ... |