NTS-NetTopologySuite中判断线是不是闭合的线

		/// <summary>
        /// 每条线都是闭合的线-首尾相连
        /// </summary>
        /// <param name="lyrPath"></param>
        /// <param name="fieldName">过滤字段</param>
        /// <param name="fieldVal">过滤值</param>
        /// <returns></returns>
        public List<IFeature> LineStringIsLinearRing(string[] lyrPaths, string fieldName, string fieldVal)
        {

            var fsAll = new List<IFeature>();
            foreach (var path in lyrPaths)
            {
                foreach (var shapefileFeature in ShpUtils.FS(path))
                {
                    fsAll.Add(shapefileFeature);
                }
            }
            var fsResult = InnerLineStringIsLinearRing(lyrPaths[0],fsAll, fieldName, fieldVal);
            return fsResult;
        }

InnerLineStringIsLinearRing方法实现：

		private List<IFeature> InnerLineStringIsLinearRing(string lyrPath, List<IFeature> fsAll, string fieldName, string fieldVal)
        {
            var tol = 0.0001;
            var dataName = Path.GetFileNameWithoutExtension(lyrPath);
            var fsResult = new List<IFeature>();
            foreach (var f in fsAll)
            {
                var fieldObj = DbaseFileHeaderEx.Attr(lyrPath, fieldName, f.Attributes);
                var coveredStart = false;
                var coveredEnd = false;
                if (f.Geometry == null || f.Geometry.IsEmpty) 
                { 
                    continue; 
                }
                Coordinate start = null;
                Coordinate end = null;
                GeometryStartEndPoints(f.Geometry, ref start, ref end);
                if(start == null || end == null)
                {
                    Commons.LogHelper.Warn(lyrPath + "几何对象不正确，无法检查");
                }
                start = f.Geometry.Coordinates[0];
                end = f.Geometry.Coordinates[f.Geometry.Coordinates.Length - 1];
                //var fieldObj = f.Attributes[fieldName];
                if (fieldObj != null && fieldObj.ToString() == fieldVal)
                {
                    if (start.Equals2D(end)) continue;
                    foreach (var f1 in fsAll)
                    {
                        if (f == f1)
                            continue;
                        if (f1.Geometry == null || f1.Geometry.IsEmpty) continue;
                        if (f1.Geometry.Distance(new Point(start)) < tol)
                            coveredStart = true;
                        if (f1.Geometry.Distance(new Point(end)) < tol)
                            coveredEnd = true;
                        if (coveredStart && coveredEnd) break;
                    }
                }
                else
                {
                    continue;
                }
                if (!(coveredStart && coveredEnd))
                {
                    fsResult.Add(f);
                }
            }
            return fsResult;
        }