Hello,I am facing a problem when trying to find intersection points between a donut like polygon and a line using ITopologicalOperator.Intersect method:
// The polygon has already been casted to ITopologicalOperator4 outside the method
private static IPointCollection5 ComputeIntersectionPoints(ITopologicalOperator4 topologialOperator, ILine normalLine) {
object obj = Type.Missing;
ISegmentCollection segCollection = new PolylineClass() as ISegmentCollection;
segCollection.AddSegment((ISegment)normalLine, ref obj, ref obj);
IGeometry resultingGeometry = segCollection as IGeometry;
topologialOperator.Simplify();
var intersectionPoints = topologialOperator.Intersect(resultingGeometry, esriGeometryDimension.esriGeometry0Dimension);
return intersectionPoints.IsEmpty ? new Point() as IPointCollection5 : (IPointCollection5)intersectionPoints;
}
I am receiving a successful intersection (intersection point) on the other boundary of the polygon but I do not get a hit on the interior border (the result of topologialOperator.Intersect(...) is always null). I have attached a sketch showing the situation. The line starts within the polygon and crosses either the exterior or interior border.Does anyone can tell me why I do not get the second intersection point. Any help would be very much appreciated! Thank you very much!
