2继续NTS库学习（读取shapefile）

引用库如下：

读取shapefile代码如下：

namespace IfoxDemo
{public class Class1{[CommandMethod("xx")]public static void nts二次学习(){Document doc = Application.DocumentManager.MdiActiveDocument;var ed = doc.Editor;string shpPath = @"C:\Users\Administrator\Desktop\1.shp";var shpPath2 = @"C:\Users\Administrator\Desktop\2.shp";foreach (var feature in NetTopologySuite.IO.Esri.Shapefile.ReadAllFeatures(shpPath2)){foreach (var attrName in feature.Attributes.GetNames()){ed.WriteMessage($"\n字段名为：\"{attrName,10}\" \n 字段内容为： \"{feature.Attributes[attrName]}\"\n");}ed.WriteMessage($"    形状和xy为\"{feature.Geometry}\"\n");break;}ed.WriteMessage("下一个：\n");foreach (var feature in NetTopologySuite.IO.Esri.Shapefile.ReadAllFeatures(shpPath)){foreach (var attrName in feature.Attributes.GetNames()){ed.WriteMessage($"字段名为：\"{attrName,10}\" \n 字段内容为： \"{feature.Attributes[attrName]}\n");}ed.WriteMessage($"     SHAPE: 形状和xy为\"{feature.Geometry}\"\n");break;}}}
}

 读取结果如下：

读取dbf文件如下：

          var ed = Env.Editor;var shpPath = @"C:\Users\Administrator\Desktop\新建文件夹 (2)\zd.shp";var dbfPath = @"C:\Users\Administrator\Desktop\新建文件夹 (2)\zd.dbf";using var dbf = new DbfReader(dbfPath);int id = 0;foreach (var record in dbf){ed.WriteMessage($"\n第{id}条记录： \n");foreach (var fieldName in record.GetNames()){ed.WriteMessage($"\n字段名为：{fieldName,10} ，字段记录内容为{record[fieldName]}。\n");}id++;}

读取shp文件的几何信息：

            var ed = Env.Editor;var shpPath = @"C:\Users\Administrator\Desktop\新建文件夹 (2)\zd.shp";var dbfPath = @"C:\Users\Administrator\Desktop\新建文件夹 (2)\zd.dbf";using var dbf = new DbfReader(dbfPath);int id = 0;foreach (NetTopologySuite.Geometries.Geometry geometry in Shapefile.ReadAllGeometries(shpPath)){id++;ed.WriteMessage($"\n第{id}个geometry:"+geometry.ToString());ed.WriteMessage("\ngeometry的类型为："+geometry.GetType().ToString()+"\n");// 根据几何类型提取坐标点List<Point3d> points = new List<Point3d>();if (geometry is Point point){// 如果是点类型points.Add(new Point3d(point.X, point.Y, point.Z)); // 假设 Z 坐标为 0}else if (geometry is LineString lineString){// 如果是线类型foreach (Coordinate coord in lineString.Coordinates){points.Add(new Point3d(coord.X, coord.Y, coord.Z)); // 假设 Z 坐标为 0}}else if (geometry is Polygon polygon){// 如果是面类型foreach (Coordinate coord in polygon.ExteriorRing.Coordinates){points.Add(new Point3d(coord.X, coord.Y, coord.Z)); // 假设 Z 坐标为 0}}// 其他几何类型（如 MultiPoint、MultiLineString、MultiPolygon 等）可以类似处理else if (geometry is  MultiPolygon multiPolygon){// 遍历 MultiPolygon 中的每个 Polygonforeach (Polygon polygon1 in multiPolygon.Geometries){// 提取外环的坐标点foreach (Coordinate coord in polygon1.ExteriorRing.Coordinates){points.Add(new Point3d(coord.X, coord.Y, coord.Z)); // 假设 Z 坐标为 0}// 提取内环的坐标点foreach (LineString interiorRing in polygon1.InteriorRings){foreach (Coordinate coord in interiorRing.Coordinates){points.Add(new Point3d(coord.X, coord.Y, coord.Z)); // 假设 Z 坐标为 0}}}}int j = 0;foreach(var pt in points){j++;ed.WriteMessage($"\n第{j}个坐标\n");ed.WriteMessage($"x:{pt.X},y:{pt.X}\n"); }}

double.NaN 是 C# 中表示 非数字（Not a Number） 的特殊值。它是 double 类型的一个常量，用于表示无效或未定义的数值结果。以下是关于 double.NaN 的详细说明：

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1. 什么是 double.NaN？

• 定义：
  NaN 是 IEEE 754 浮点数标准中定义的一个特殊值，表示 非数字。

• 特点：

  • 它不是任何具体的数值。

  • 它用于表示无效的数学运算结果（如 0 / 0 或 Math.Sqrt(-1)）。

  • 它与任何值（包括它自己）的比较结果都是 false。