C#根据经纬度请求返回坐标实际地址

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Globalization;
using System.Net;
using System.IO;
using System.Configuration;
using System.Xml;
namespace WSGPSGateway.BLL
{
    public class LocationAPI
    {
        private static string GeoCodeUrl = ConfigurationManager.AppSettings["GeoCodeUrl"];
        private static string GoogleGearUrl = ConfigurationManager.AppSettings["GoogleGearUrl"];
        private static string UseGoogleReverse = ConfigurationManager.AppSettings["UseGoogleReverse"];
        /// <summary>
        /// Initializes a new instance of the <see cref="LocationAPI"/> class.
        /// </summary>
        public LocationAPI()
        {
        }
        public static string GetAddressFromLL(string Lat, string Lng)
        {
            string url = "http://ws.geonames.org/findNearestAddress?lat=" + Lat + "&lng=" + Lng;
            WebResponse response = null;
            Stream stream = null;
            StreamReader reader = null;
            try
            {
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
                request.UserAgent = @"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 2.0.40607; .NET CLR 1.1.4322)";
                request.Timeout = 1;
                response = request.GetResponse();
                stream = response.GetResponseStream();
                reader = new StreamReader(stream, System.Text.Encoding.UTF8);
                XmlDocument xDoc = new XmlDocument();
                xDoc.Load(stream);
                XmlNode xStreet = xDoc.SelectSingleNode("geonames/address/street");
                XmlNode xStreetNumber = xDoc.SelectSingleNode("geonames/address/streetNumber");
                XmlNode xPlacename = xDoc.SelectSingleNode("geonames/address/placename");
                XmlNode xCountryCode = xDoc.SelectSingleNode("geonames/address/countryCode");
                string address = xStreet.InnerText + " " + xStreetNumber.InnerText + ", " + xPlacename.InnerText + ", " + xCountryCode.InnerText + " ";
                return address;
            }
            catch(Exception ex)
            {
                DAL.Log.Write(DateTime.Now.ToString() + "\0" + ex.Message.ToString() + "\r\n");
                return "UnKnown";
            }
            finally
            {
                if (reader != null) reader.Close();
                if (stream != null) stream.Close();
                if (response != null) response.Close();
            }
        }
    }
}