Using own geometries

Example

Discussion - copying geometries

This is a particular solution that may be applied when fully 'digested' geometries need to be provided to a client system (e.g. for graphical visualization, spatial calculations, etc.), while the actual geometry is defined as an aggregation of other Airspace. The method consists in effectively copying the geometry of the referenced Airspace as local AirspaceVolume.

The disadvantage of this method is that the referenced geometry might also change in time. This is not a problem when the aggregation is used for the provision of SNAPSHOT data (valid at a time instant), but it might become problematic when providing BASELINE data (which is valid for a period). Future changes of the geometry of referenced airspace needs to be propagated to the AirspaceVolume of the aggregated airspace.

The advantage is that this method provides complete geometrical data for the aggregated Airspace and does not require further calculations by the client system.

For this method, the AirspaceGeometryComponent class is used to define the aggregation, and the Surface class to define the lateral limits of the child airspace (viz. the copies of the lateral limits of the 'parent airspace').

The figure below illustrates a simple copying of geometry, using as an example the BRUSSELS TMA, which is a union of two parts: TMA one and TMA two:

There is an additional option here. Instead of coping the geometry of the existing parts, the parts may be defined as integral part of the geometry of the child airspace. In this case, the parent airspace does not exist as own instance of the airspace feature.