private static int Wind(GeographicalPoint location, Edge edge, Position position)
{
if (edge.RelativePositionOf(location) != position)
{
return(0);
}
return(1);
}
public bool LocationInRange(GeographicalPoint location, Orientation orientation)
{
if (orientation == Orientation.Ascending)
{
return(_endPoint.Latitude > location.Latitude);
}
return(_endPoint.Latitude <= location.Latitude);
}
private static int DescendingIntersection(GeographicalPoint location, Edge edge)
{
if (edge.AscendingRelativeTo(location))
{
return(0);
}
if (!edge.LocationInRange(location, Orientation.Descending))
{
return(0);
}
return(Wind(location, edge, Position.Right));
}
public bool Contains(GeographicalPoint location)
{
GeographicalPoint[] polygonPointsWithClosure = PolygonPointsWithClosure();
int windingNumber = 0;
for (int pointIndex = 0; pointIndex < polygonPointsWithClosure.Length - 1; pointIndex++)
{
Edge edge = new Edge(polygonPointsWithClosure[pointIndex], polygonPointsWithClosure[pointIndex + 1]);
windingNumber += AscendingIntersection(location, edge);
windingNumber -= DescendingIntersection(location, edge);
}
return(windingNumber != 0);
}
public Position RelativePositionOf(GeographicalPoint location)
{
double positionCalculation =
(_endPoint.Longitude - _startPoint.Longitude) * (location.Latitude - _startPoint.Latitude) -
(location.Longitude - _startPoint.Longitude) * (_endPoint.Latitude - _startPoint.Latitude);
if (positionCalculation > 0)
{
return(Position.Left);
}
if (positionCalculation < 0)
{
return(Position.Right);
}
return(Position.Center);
}
public Edge(GeographicalPoint startPoint, GeographicalPoint endPoint)
{
_startPoint = startPoint;
_endPoint = endPoint;
}
public bool AscendingRelativeTo(GeographicalPoint location)
{
return(_startPoint.Latitude <= location.Latitude);
}
