Geometry (Overview)

The geometry package of the AIXM 5.1(.1) conceptual model (UML) contains the definition of the classes that model general geometrical aspects. These classes are based on the ISO 19107 Spatial schema.

3D geometries are represented as 2D projections with additional AIXM feature properties specifying the vertical dimension, such as elevation, geoid undulation, vertical datum, upper and lower limit, upper and lower limit reference. This approach is also known as "2.5D", since the vertical dimensions/positions are actually represented as feature properties, not as genuine geometrical elements. This is mainly due to the fact that pressure-based references (such as flight levels) and geoid-based references (altitude above means sea level) are used in the definition of airspace, routes, procedures, etc.

Additional AIXM feature properties are provided for accuracy (horizontal and vertical).

In addition, AIXM 5.1(.1) also augments the ISO 1907 geometries with additional geometrical concepts specific to the aeronautical information domain, such as Bearings, Distances from Significant Points, Airspace aggregation etc.