首先需要有基本的经纬度文件

    1. /// <summary>
    2.         /// 保存kml文件
    3.         /// </summary>
    4.         /// <param name="overlayname"></param>
    5.         private void SaveKml(string overlayname)
    6.         {
    7.             string filePath = FilePaths.Find(a => a.Contains(overlayname.Trim()));
    8.             List<string[]> latlngs = new List<string[]>();
    9.             ReadFormatTxt(filePath, ref latlngs);//读格式的文件返回经纬度
    10.             filePath = filePath.Substring(0, filePath.LastIndexOf(".")) + ".kml";
    11.             string s = "";
    12.             foreach (string[] ss in latlngs)
    13.             {
    14.                 s += string.Format("{0},{1},{2}", ss[0], ss[1], 0) + " ";
    15.             }
    16.             if (!string.IsNullOrEmpty(s))
    17.             { SaveKml(filePath, s); }
    18.         }
    20.         private void SaveKml(string filepath, string xml)
    21.         {
    22.             //生成KML文件，注意大小写
    23.             FileStream fs = new FileStream(filepath, FileMode.Create);
    24.             XmlTextWriter w = new XmlTextWriter(fs, Encoding.UTF8);
    25.             // 开始文档
    26.             w.Formatting = System.Xml.Formatting.Indented;
    27.             w.WriteStartDocument();
    28.             w.WriteStartElement("kml", "http://www.opengis.net/kml/2.2");
    29.             //开始一个元素
    30.             w.WriteStartElement("Document");
    31.             //添加子元素
    32.             w.WriteElementString("name", "Paths");
    33.             w.WriteElementString("description", "Examples of paths.");
    35.             w.WriteStartElement("Style");
    36.             //向先前创建的元素中添加一个属性
    37.             w.WriteAttributeString("id", "yellowLineGreenPoly");
    39.             w.WriteStartElement("LineStyle");
    40.             w.WriteElementString("System.Drawing.Color", "7f00ffff");
    41.             w.WriteElementString("width", "4");
    42.             w.WriteEndElement();
    44.             w.WriteStartElement("PolyStyle");
    45.             w.WriteElementString("System.Drawing.Color", "7f00ffff");
    46.             w.WriteEndElement();
    47.             // 关闭style元素
    48.             w.WriteEndElement();
    50.             w.WriteStartElement("Placemark");
    51.             w.WriteElementString("name", "Absolute Extruded");
    52.             w.WriteElementString("description", "Transparent green wall with yellow outlines");
    53.             w.WriteElementString("styleUrl", "#yellowLineGreenPoly");
    55.             w.WriteStartElement("LineString");
    56.             w.WriteElementString("extrude", "1");
    57.             w.WriteElementString("tessellate", "1");
    58.             w.WriteElementString("altitudeMode", "clampedToGround");
    60.             w.WriteStartElement("coordinates");
    62.             // 将路径坐标写在这里           
    63.             w.WriteString(xml);
    65.             // 关闭所有元素
    66.             w.WriteEndDocument();
    68.             // 关闭流
    69.             w.Close();
    70.             fs.Close();
    71.         }

    这句比较重要，可以把xml文件从一行的形式，改成正常的多行形式
    xmlWriter.Formatting = System.Xml.Formatting.Indented;