/// <summary>
/// Returns all polygon points from given airspace polygon object
/// </summary>
/// <param name="polygon">airspace polygon</param>
/// <param name="floor">floor altitude</param>
/// <returns>position list object with all polygon points</returns>
private static Czml.PositionList GetPolygonPointsFromAirspacePolygon(Airspace.Polygon polygon, Altitude floor)
{
double height = HeightFromAltitude(floor);
var positions = new Czml.PositionList();
foreach (var segment in polygon.Segments)
{
if (segment is Airspace.Polygon.PolygonPoint point)
{
positions.Add(point.Point.Latitude, point.Point.Longitude, height);
}
if (segment is Airspace.Polygon.PolygonArc arc)
{
var convertedArcSegment = ConvertPolygonArcToArcSegment(arc, height);
AddArcSegmentPolygonPoints(convertedArcSegment, positions, height);
positions.Add(arc.End.Latitude, arc.End.Longitude, height);
}
if (segment is Airspace.Polygon.PolygonArcSegment arcSegment)
{
AddArcSegmentPolygonPoints(arcSegment, positions, height);
}
}
return(positions);
}
/// <summary>
/// Creates a Czml.Object from given airspace
/// </summary>
/// <param name="airspace">airspace to use</param>
/// <returns>created CZML object</returns>
private static Czml.Object CzmlObjectFromAirspace(Airspace.Airspace airspace)
{
double height = HeightFromAltitude(airspace.Ceiling) - HeightFromAltitude(airspace.Floor);
if (airspace.Geometry is Circle circle)
{
return(new Czml.Object
{
Name = airspace.Name,
Description = DescriptionFromAirspace(airspace),
Position = PositionFromCoord(circle.Center, airspace.Floor),
Cylinder = new Czml.Cylinder
{
BottomRadius = circle.Radius,
TopRadius = circle.Radius,
Length = height,
HeightReference = HeightReferenceFromAltitude(airspace.Floor),
Material = MaterialFromAirspace(airspace),
Outline = true,
OutlineColor = ColorFromAirspace(airspace, outlineColor: true),
},
});
}
if (airspace.Geometry is Airspace.Polygon polygon)
{
Czml.PositionList positions = GetPolygonPointsFromAirspacePolygon(polygon, airspace.Floor);
if (!positions.CartographicDegrees.Any())
{
return(null);
}
return(new Czml.Object
{
Name = airspace.Name,
Description = DescriptionFromAirspace(airspace),
Polygon = new Czml.Polygon
{
Positions = positions,
Height = HeightFromAltitude(airspace.Floor),
ExtrudedHeight = HeightFromAltitude(airspace.Ceiling),
HeightReference = HeightReferenceFromAltitude(airspace.Floor),
Material = MaterialFromAirspace(airspace),
Outline = true,
OutlineColor = ColorFromAirspace(airspace, outlineColor: true),
},
});
}
throw new FormatException("invalid airspace geometry");
}
/// <summary>
/// Generates all points for a PolygonArcSegment object and adds it to the positions
/// </summary>
/// <param name="arcSegment">arc segment to use</param>
/// <param name="positions">positions to add to</param>
/// <param name="height">height value</param>
private static void AddArcSegmentPolygonPoints(
Airspace.Polygon.PolygonArcSegment arcSegment,
Czml.PositionList positions,
double height)
{
var center = arcSegment.Center.ToMapPoint(height);
bool isClockwise = arcSegment.Direction == Airspace.Polygon.ArcDirection.Clockwise;
double endAngle = arcSegment.EndAngle;
double startAngle = arcSegment.StartAngle;
// adjust angles so that we don't have to deal with wrap around
if (isClockwise && startAngle > endAngle)
{
endAngle += 360.0;
}
if (!isClockwise && startAngle < endAngle)
{
startAngle += 360.0;
}
bool isAtEnd;
double step = (isClockwise ? 1.0 : -1.0) * ArcSegmentAngleStepByRadius(arcSegment.Radius);
double bearing = startAngle;
do
{
var point = center.PolarOffset(arcSegment.Radius, -bearing, height);
positions.Add(point.Latitude, point.Longitude, height);
bearing += step;
isAtEnd = isClockwise
? bearing > endAngle
: bearing < endAngle;
}while (!isAtEnd);
// add end point when the step angle didn't hit the end angle directly
if (Math.Abs(bearing - arcSegment.EndAngle) > 1e-6)
{
var point = center.PolarOffset(arcSegment.Radius, -arcSegment.EndAngle, height);
positions.Add(point.Latitude, point.Longitude, height);
}
}