How to get all self-intersecting points in polygon

[Raimond]

Hi,

Maybe someone can help me, how can I get all self-intersection points in polygon?

I wrote this simple C# function:

private void CollectAlIntersections(IGeometry g)

        {

            List<ICoordinate> invalidPoints = new List<ICoordinate>();

            GeometryGraph geomGraph = new GeometryGraph(0, g);

            LineIntersector li = new RobustLineIntersector();

            SegmentIntersector intersector = geomGraph.ComputeSelfNodes(li, true);

            if (intersector.HasProperIntersection)

            {

                ICoordinate invalidPoint = intersector.ProperIntersectionPoint;

                invalidPoints.Add(invalidPoint);

            }

        }

Problem is that I'm always getting only one intersection point althought polygon has at least 4 self-intersecting points. Can anyone help me?

[FObermaier]

The following lines should work:

private void CollectAllIntersections(IGeometry g, out IList<Coordinate> invalidPoints)

{

    invalidPoints = null;

    var iif = InteriorIntersectionFinder.CreateAllIntersectionsFinder(new RobustLineIntersector());

    var noder = new MCIndexNoder(iif);

    noder.ComputeNodes(SegmentStringUtil.ExtractNodedSegmentStrings(g));

    if (iif.Count > 0)

        invalidPoints = iif.Intersections;

}