【WebAPI】高德地图根据GPS获取地址

【WebAPI】高德地图根据GPS获取地址：通过调用高德的WebApi，将经纬度转换为地址描述。

        const string KEY = "这个地方填写你申请的高德WebAPIKey";
        /// 

        /// 根据GPS地址获取中文详细地址
        /// 
        ///经度
        ///维度
        ///匹配半径，单位为米
        /// 中文详细地址
        public static string GPSToPositionString(double lon, double lat, int radius = 1000)
        {
            WebClient server = new WebClient();
            string url = String.Format("https://restapi.amap.com/v3/geocode/regeo?location={0},{1}&key={2}&radius={3}&extensions=base", lon, lat, KEY, radius);
            var replyBuffer = server.DownloadData(url);
            var reply = System.Text.Encoding.UTF8.GetString(replyBuffer);
            if (String.IsNullOrEmpty(reply))
                return "";
            JObject result = (JObject)JsonConvert.DeserializeObject(reply);
            if (result["status"].Value() == "1")
            {
                var regeocode = result["regeocode"];
                var formatted_address = regeocode["formatted_address"];
                return formatted_address.Value();
            }
            else
                return "";
        }