Gps坐标(在C#中解析Xml文件)

我必须编写一个WebService方法.并且此方法将采用纬度"，经度"和距离"参数.如果距离接近我们的节点，它将向我们显示最近的节点.
所以我写了一些东西，但我无法使它更清晰，更详细.你能帮我么??而且我也有一个XML文件.文件中有地址和分支...
谢谢！

I have to write a WebService Method. And this method going to take a Latitude, a Longitude and distance parameters. If the distance is close to our node, it is going to show us the nearest nodes.
So I wrote something but I cannot make it clear and more detailed. Can you please help me?? And also I have got a XML file too. There are addresses and Branches in the file ...
Thanks !

using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Xml;
namespace Proje
{
    public class DistanceHelper
    {
        private double GetDistanceBetweenPoints(double lat1, double long1, double lat2, double long2)
        {
            double distance = 0;
            double dLat = (lat2 - lat1) / 180 * Math.PI;
            double dLong = (long2 - long1) / 180 * Math.PI;
            double a = Math.Sin(dLat / 2) * Math.Sin(dLat / 2)
                        + Math.Cos(lat2) * Math.Sin(dLong / 2) * Math.Sin(dLong / 2);
            double c = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));

            double radiusE = 6378135;
            double radiusP = 6356750;

            double nr = Math.Pow(radiusE * radiusP * Math.Cos(lat1 / 180 * Math.PI), 2);
            double dr = Math.Pow(radiusE * Math.Cos(lat1 / 180 * Math.PI), 2)
                            + Math.Pow(radiusP * Math.Sin(lat1 / 180 * Math.PI), 2);
            double radius = Math.Sqrt(nr / dr);
            distance = radius * c;
            return distance;
        }

        public DataTable GetAppropriateBranches(int longtitude, int latitude, decimal distance)
        {
            DataTable dTable = new DataTable();
            XmlDocument xmlDoc = GetXmlDocument();
            DataTable returnValue = CreateDataTable();

            XmlNode mainNode = xmlDoc.ChildNodes[1];
            foreach (XmlNode childNode in mainNode.ChildNodes)
            {
                DataRow dRow = returnValue.NewRow();
                dRow["Adres"] = childNode.Attributes["Address"];
                dRow["Sube"] = childNode.Attributes["Branch"];
                returnValue.Rows.Add(dRow);
            }



            return dTable;
        }

        private DataTable CreateDataTable()
        {
            throw new NotImplementedException();
        }
        private XmlDocument GetXmlDocument()
        {
            throw new NotImplementedException();
        }
    }
}</pre>


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<pre lang="cs">using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Xml.Linq;
using System.Xml;
namespace Proje
{
    /// &lt;summary&gt;
    /// Summary description for Service1
    /// &lt;/summary&gt;
    [WebService(Namespace = &quot;http://tempuri.org/&quot;)]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
    // [System.Web.Script.Services.ScriptService]
    public class Service1 : System.Web.Services.WebServicec
    {
        [WebMethod]
        public DataTable GetAppropriateBranches(int longtitude, int latitude, decimal distance)
        {
            return new DistanceHelper().GetAppropriateBranches(longtitude, latitude, distance);
        }
    }
}