Purpose and Scope
These pages contain the coding guidelines for the minimum and conditional data items related to the "Waypoint - en-route" subject as defined in PANS-AIM.
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At the beginning of this page the different terms Designated Point, Significant Point and Waypoint which are used in the avaition domain shall be discussed.
Sigificant Point
A Significant Point is defined by ICAO Annex 11
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In AIXM the SignificantPoint class could be seen as a 'placeholder' for a Navaid, Runway Point (e.g. a Threshold Position), Airport Reference Point, Aiming Point of a TLOF, Designated Point or a simple Point in space. At a conceptual level, it simplifies the model by significantly reducing the number of relationships.
Designated Point
A term that is only defined by AIXM. The 'Designated Point' definition is derived from the Significant Point definition, by difference:
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In AIXM a DesigantedPoint is a specialisation of a SignificantPoint.
Waypoint
The term waypoint is not used in AIXM but in ICAO documents:
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In AIXM the class DesignatedPoint is used in order to model points that have an official (5 letter) designator, have specified coordinates and do not mark the position of a Navaid. This includes, but is not limited to, 'waypoints' as many Designated Points are used for purposes other than defining a RNAV route.
Summary
The term significant point is the most generic one. It includes designated points but also Navaids, etc. The term designated point excludes navaids. It includes but is not limited to waypoints. Often, a designated points will have an official (5 letter) designator. The term waypoints are exculsivly used in the RNAV context.
AIXM Model Overview
The figure below shows the main AIXM 5 classes used for the Designated Point concept:
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