This example shows how the AIP information about for the geometry of an airspace (TMA AQUITAINE part 2-1) is used to calculate for computing the AIXM/GML digital representation of the horizontal projection of that Airspace.
...
- distance from center to point A: 22.942 NM (0.25% difference to 23 NM)
- distance from center to point B: 22.941 NM (0.26% difference to 23 NM)
Therefore, the official AIP radius value of 23 NM, as declared in the AIP, may be safely directly used in the GML encoding. If the difference was higher than 1%, the data originator should be contacted in order to provide a more accurate value for the arc radius.
...