NDBG_LCS/Kingo.PluginServiceInterface/Helper/PartiallyNarrow.cs

using System;
using System.Collections.Generic;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;
using KGIS.Framework.AE.ExtensionMethod;
using KGIS.Framework.AE;

namespace Kingo.PluginServiceInterface.Helper
{
    public class PolygonNarrowCheck
    {
        public static bool CheckNarrowArea1(IGeometry geometry)
        {
            bool isSharpAngle = false;
            try
            {
                if (geometry == null || geometry.IsEmpty) return isSharpAngle;
                ITopologicalOperator topo = geometry as ITopologicalOperator;
                IPolyline line1 = topo.Boundary as IPolyline;
                double length1 = line1.Length;
                int pointCount1 = (geometry as IPointCollection).PointCount;
                IGeometry geo = topo.Buffer(-0.05);
                ITopologicalOperator topo2 = geo as ITopologicalOperator;
                IPolyline line2 = topo2.Boundary as IPolyline;
                double length2 = line2.Length;
                double delta_length = length1 - length2;
                double avg_halfangle = 180 * (pointCount1 - 1 - 2) / (pointCount1 - 1) / 2;
                double conner_normal_length = 2 * 0.05 / Math.Tan(avg_halfangle * (Math.PI / 180));
                if (delta_length > 8 * conner_normal_length * (pointCount1 - 1))
                    return true;
            }
            catch (Exception)
            {

            }
            finally
            {
                //GC.Collect();
            }
            return isSharpAngle;
        }

        // 经验阈值判断（8倍安全系数）
        const double safetyFactor = 8.0;
        const double bufferDistance = -0.05; // 单位取决于空间参考
        public static bool CheckNarrowArea(IGeometry geometry)
        {
            // 返回值表示是否检测到狭窄区域，默认为false
            bool isNarrowAreaDetected = false;
            try
            {
                // 输入校验：确保几何体非空且有效
                if (geometry == null || geometry.IsEmpty)
                    return isNarrowAreaDetected;
                // 类型检查：确保支持拓扑操作
                if (!(geometry is ITopologicalOperator topoOperator))
                    return isNarrowAreaDetected;
                // 获取原始边界并验证类型
                var originalBoundary = topoOperator.Boundary as IPolyline;
                if (originalBoundary == null)
                    return isNarrowAreaDetected;
                // 计算原始几何参数
                double originalLength = originalBoundary.Length;
                int vertexCount = (geometry as IPointCollection)?.PointCount ?? 0;
                // 顶点数不足3时无法构成有效多边形
                if (vertexCount < 3)
                    return isNarrowAreaDetected;
                // 执行负缓冲操作（缩小几何体）
                IGeometry bufferedGeometry = topoOperator.Buffer(bufferDistance);
                // 检查缓冲后几何有效性
                if (bufferedGeometry?.IsEmpty != false)
                    return isNarrowAreaDetected;
                // 获取缓冲后边界并验证类型
                if (!(bufferedGeometry is ITopologicalOperator bufferedTopo))
                    return isNarrowAreaDetected;
                var bufferedBoundary = bufferedTopo.Boundary as IPolyline;
                if (bufferedBoundary == null)
                    return isNarrowAreaDetected;
                // 计算缓冲后长度差异
                double deltaLength = originalLength - bufferedBoundary.Length;
                // 计算平均内角半角（几何修正）
                double avgHalfAngle = 90.0 * (vertexCount - 2) / vertexCount;

                // 角度接近直角时跳过计算（避免tan(90°))
                if (avgHalfAngle >= 89.999)
                    return isNarrowAreaDetected;
                // 计算拐角缩短长度
                double tanValue = Math.Tan(avgHalfAngle * Math.PI / 180.0);
                double cornerReduction = 2 * Math.Abs(bufferDistance) / tanValue;
                // 计算总预期缩短长度
                double totalExpectedReduction = cornerReduction * vertexCount;
                isNarrowAreaDetected = deltaLength > safetyFactor * totalExpectedReduction;
            }
            catch (Exception ex)
            {
                // 异常处理（建议记录日志）
                // Debug.WriteLine($"几何检测异常: {ex.Message}");
                return false;
            }

            return isNarrowAreaDetected;
        }
    }
}