The European Organisation for the Safety of Air Navigation OGC Aviation Domain Working Group - GML Guidelines / Profile -

2 Guidance and Profile of GML for use with Aviation Data Published: MAY 2012 by OGC (produced by the Aviation Domain WG) Status: OGC Discussion Paper ( ) 1 st part - Encoding guidelines for aviation specific data srsName (WGS 84 is imposed in aviation) Surface and lines - specials Parallels Arcs Embedded curves/points Geographical borders re-used in Surface definitions In relation with the use of AIXM for aeronautical data encoding 2 nd part - GML Profile

3 Why guidelines AIXM 4.5 – non GML AIXM 5.1– GML

4 Positions - encoding … … First latitude, then longitude

5 Straight lines gml:Geodesic gml:GeodesicString … …

6 Parallels Linear interpolation -> parallel Longitude axis Latitude axis (NORTH) Lat 1 Long1 Lat 1 Long2 Linear interpolation in a geodetic CRS

7 Arc by centre point lat_P3 long_P3 radius calculated_start_angle calculated_end_angle gml:ArcByCenterPoint

8 Point references * Edge point * Centre point * Etc. “E) AIR DISPLAY WILL TAKE PLACE WI LATERAL LIMITS: N E (NDB OBR) N E (VILLAGE JAKOVO) N E N E (NDB OBR). gml:pointProperty

9 With annotation VILLAGE JAKOVO information provided is “for human consumption”

10 With xlink:href Local Or with remote references to the feature! Looking into other xlink attributes… include xlink:title for display purpose

11 AIXM 5.1 Guidelines 2 nd part: GML Profile

12 GML Profile Table 2 – AIXM Conceptual Types and the relevant XSD Implementation to document AIXM Conceptual Type AIXM XSD Implementation (Element and Type) Section Reference Pointaixm:Point, -Type9.3.2 ElevatedPointaixm:ElevatedPoint, -Type9.3.3 Curveaixm:Curve, -Type9.3.4 ElevatedCurveaixm:ElevatedCurve, -Type9.3.5 Surfaceaixm:Surface, -Type9.3.6 ElevatedSurfaceaixm:ElevatedSurface, -Type9.3.7

13 GML Profile ISO TypeISO / GML Implementation (Element and Type) Section Reference DirectPositiongml:pos, gml:DirectPositionType9.4.2 GM_Pointgml:Point, -Type9.4.3 GM_Envelopegml:Envelope, -Type9.4.4 GM_PointRefgml:pointProperty, gml:PointPropertyType9.4.5 GM_PositionDefined in GML as a group, not as an element/type: gml:geometricPositionGroup GM_PointArraygml:posList, gml:DirectPositionListType gml:AbstractCurve, -Type9.4.8 GM_Curvegml:Curve, -Type9.4.9 GM_CurveSegmentgml:AbstractCurveSegment, -Type9.4.10

14 GML Profile -gml:ArcByCenterPoint, -Type gml:CircleByCenterPoint, -Type GM_Arcgml:Arc, -Type GM_Circlegml:Circle, -Type GM_GeodesicStringgml:GeodesicString, -Type GM_Geodesicgml:Geodesic, -Type GM_LineStringgml:LineStringSegment, -Type GM_Surfacegml:Surface, -Type GM_SurfacePatchgml:AbstractSurfacePatch, -Type GM_Polygongml:PolygonPatch, -Type gml:AbstractRing, -Type GM_Ringgml:Ring, -Type GM_OrientableCurvegml:OrientableCurve, -Type GM_CompositeCurvegml:CompositeCurve, -Type9.4.24

15 GML Profile – example of an element XSD Elementgml:Curve Typegml:CurveType BaseTypegml:AbstractCurveType Restrictionnone UsageTo represent spatial properties of aeronautical features with 1D shape (e.g. the centerline of an airspace corridor) but also the boundaries of a 2D shape (e.g. the exterior of an airspace). DefinitionA curve is a 1-dimensional primitive. Curves are continuous, connected, and have a measurable length in terms of the coordinate system. A curve is composed of one or more curve segments. Each curve segment within a curve may be defined using a different interpolation method. The curve segments are connected to one another, with the end point of each segment except the last being the start point of the next segment in the segment list. The orientation of the curve is positive. The element “ segments ” encapsulates the segments of the curve. Comments The orientation of a curve can be inverted using an OrientableCurve as wrapper – see section for further details. Used inUsed as parent type for AIXM Curve (see section 9.3.4). Can be used in the definition of a surface boundary (see Figure 22 and section ).

16 GML Profile – example of an element XML Schema File(./ISO_19136_Schemas/) geometryPrimitives.xsd XML Schema Component Example lat_P1 long_P1 lat_P2 long_P2 lat_P3 long_P3 radius calculated_start_angle calculated_end_angle lat_P4 long_P4 lat_P5 long_P5

The European Organisation for the Safety of Air Navigation