using System;

using System.Collections.Generic;

using NetTopologySuite.Geometries;

using NetTopologySuite.IO;

using NetTopologySuite.Operation.Polygonize;

using NetTopologySuite.Features;

using NetTopologySuite.Operation.Union;

using NetTopologySuite;

using NetTopologySuite.Geometries.Utilities;

public class Program

{

    public static void Main()

    {

        var geometry = "GEOMETRYCOLLECTION(POLYGON((-0.328794689 50.897369966,-0.320831211 50.896106249,-0.320624681 50.896894595,-0.323505372492192 50.89326741259052,-0.328794689 50.897369966)))";

        string fixedWkt = FixSelfIntersectingGeometry(geometry);

​

        if (fixedWkt != null)

        {

            Console.WriteLine($"Fixed Geometry (WKT): {fixedWkt}");

        }

        else

        {

            Console.WriteLine("Geometry could not be fixed.");

        }

    }

    public static string FixSelfIntersectingGeometry(string wktGeometry)

    {

        try

        {

            var wktReader = new WKTReader();

            Geometry geom = wktReader.Read(wktGeometry);

​

            if (!geom.IsValid)

            {

                Geometry fixedGeom = GeometryFixer.Fix(geom);

                var wktWriter = new WKTWriter();

                return wktWriter.Write(fixedGeom);

            }

            else

            {

                return wktGeometry; //Geometry is already Valid

            }

        }

        catch (Exception ex)

        {

            Console.WriteLine($"Error fixing geometry: {ex.Message}");

            return null;

        }

    }

}