高德地图：地理/逆地理编码

高德API：http://lbs.amap.com/api/webservice/guide/api/georegeo/

http://restapi.amap.com/v3/geocode/geo?key=7de8697669288fc848e12a08f58d995e&s=rsv3&city=杭州市&address=杭州市天成路87号现代大厦

这里边的key是别人开放的key，用起来感觉还可以。基本上没有太大的限制，使用上边的接口获取经纬度是基本上100%成功，但是这个坐标系是GCJ02坐标。

按照上边的接口可以返回的结果信息为：

{"status":"1","info":"OK","infocode":"10000","count":"1","geocodes":[{"formatted_address":"浙江省杭州市江干区现代大厦","province":"浙江省","citycode":"0571","city":"杭州市","district":"江干区","township":[],"neighborhood":{"name":[],"type":[]},"building":{"name":[],"type":[]},"adcode":"330104","street":[],"number":[],"location":"120.204319,30.287145","level":"兴趣点"}]}

 根据GPS格式的经纬度，调用高德API返回具体地址信息：

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            string address = GetAddressByGcjLngLat("120.204319", "30.287145");

            Console.WriteLine(address);
            Console.ReadKey();
        }

        /// <summary>
        /// 根据GPS经纬度，返回对应位置的地址信息。
        /// 请求API:http://restapi.amap.com/v3/geocode/regeo?output=json&location=120.204319,30.287145&key=7de8697669288fc848e12a08f58d995e&radius=100&extensions=base
        /// </summary>
        /// <param name="longitude"></param>
        /// <param name="latitude"></param>
        /// <returns></returns>
        public static string GetAddressByGcjLngLat(string longitude, string latitude)
        {
            Tuple<bool, string, string> gcjLngLat = TransformGPS2GCJ(longitude, latitude);
            // Console.WriteLine("{0}:{1}:{2}", gcjLngLat.Item1, gcjLngLat.Item2, gcjLngLat.Item3);

            if (false == gcjLngLat.Item1)
                return string.Empty;

            string address = string.Empty;

            try
            {
                // 格式：http://restapi.amap.com/v3/geocode/regeo?output=json&location=120.204319,30.287145&key=7de8697669288fc848e12a08f58d995e&radius=100&extensions=base
                string content = HttpGet("http://restapi.amap.com/v3/geocode/regeo?output=json&location=" + gcjLngLat.Item2 + "," + gcjLngLat.Item3 + "&key=7de8697669288fc848e12a08f58d995e&radius=200&extensions=base");
                // 返回值格式：{"status":"1","info":"OK","infocode":"10000","regeocode":{"formatted_address":"浙江省杭州市江干区闸弄口街道万家花园(天城路)","addressComponent":{"country":"中国","province":"浙江省","city":"杭州市","citycode":"0571","district":"江干区","adcode":"330104","township":"闸弄口街道","towncode":"330104007000","neighborhood":{"name":"万家花园(天城路)","type":"商务住宅;住宅区;住宅小区"},"building":{"name":[],"type":[]},"streetNumber":{"street":"天城路","number":"87号","location":"120.204319,30.2871444","direction":"南","distance":"0.0617778"},"businessAreas":[{"location":"120.20604745161295,30.28125106451613","name":"火车东站","id":"330104"}]}}}

                string[] adddressItems = content.Replace(""", string.Empty).Split(new char[] { '{', ',', '}', '[', ']' });
                if (adddressItems != null && adddressItems.Length > 0)
                {
                    foreach (string addressItem in adddressItems)
                    {
                        if (addressItem.StartsWith("formatted_address:", StringComparison.OrdinalIgnoreCase))
                        {
                            address = addressItem.Replace("formatted_address:", string.Empty);
                            break;
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                // 出现异常，返回转化失败且不扑捉异常信息。
            }

            // Console.WriteLine(address);
            return address;
        }

        /// <summary>
        /// 接口地址
        ///         http://api.zdoz.net/transmore.ashx
        /// 接口说明
        /// 批量纠偏，一次最大可纠偏1000个坐标点
        ///     参数
        /// lats:维度，多个维度用“;”隔开
        /// lngs:经度，多个经度用“;”隔开（要注意经纬度个数相等）
        /// type:转换类型 【1.WGS -> GCJ】 【2.GCJ -> WGS】 【3.GCJ -> BD】 【4.BD -> GCJ】 【5.WGS -> BD】 【6.BD -> WGS】
        ///     返回值JSON
        /// 根据次序返回一个json格式的数组
        ///     演示
        /// 参数：lats=34.123;34.332;55.231&lngs=113.123;112.213;115.321&type=1
        /// 返回：[{"Lng":113.12942937312582,"Lat":34.121761850760855},{"Lng":112.21911710957568,"Lat":34.3306763095054}, {"Lng":115.33036232125529,"Lat":55.232930158541052}]
        /// </summary>
        /// <param name="lngGPS">gps格式的经度，将会被转化为GCJ02格式的经度</param>
        /// <param name="latGPS">gps格式的纬度，将会被转化为GCJ02格式的纬度</param>
        /// <returns>(bool:是否转化成功,string:gcj02格式的经度,string:gcj02格式的纬度)</returns>
        public static Tuple<bool, string, string> TransformGPS2GCJ(string lngGPS, string latGPS)
        {
            Tuple<bool, string, string> result = new Tuple<bool, string, string>(false, string.Empty, string.Empty);
            try
            {
                // 格式：http://api.zdoz.net/transmore.ashx?lats=34.123&lngs=113.123&type=1
                string content = HttpGet("http://api.zdoz.net/transmore.ashx?lats=" + latGPS + "&lngs=" + lngGPS + "&type=1");
                // 返回值格式：[{"Lng":113.12942937312582,"Lat":34.121761850760855}]
                content = content.Replace("[{", string.Empty).Replace("}]", string.Empty).Replace(""", string.Empty);
                string[] lngLatItems = content.Split(new char[] { ',' });
                if (lngLatItems != null && lngLatItems.Length == 2 && lngLatItems[0].StartsWith("lng", StringComparison.OrdinalIgnoreCase) && lngLatItems[1].StartsWith("lat", StringComparison.OrdinalIgnoreCase))
                {
                    result = new Tuple<bool, string, string>(true, lngLatItems[0].ToLower().Replace("lng:", string.Empty), lngLatItems[1].ToLower().Replace("lat:", string.Empty));
                }
            }
            catch (Exception ex)
            {
                // 出现异常，返回转化失败且不扑捉异常信息。
            }

            return result;
        }

        /// <summary>
        /// Get访问uri并反回请求响应内容。
        /// </summary>
        /// <param name="uri"></param>
        /// <param name="timeout">请求超时时间，默认：30s超时</param>
        /// <returns></returns>
        public static string HttpGet(string uri, int timeout = 30 * 1000)
        {
            string result = string.Empty;

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
            request.Method = "GET";
            request.ContentType = "text/html;charset=UTF-8";
            request.Timeout = timeout;

            using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
            {
                using (Stream myResponseStream = response.GetResponseStream())
                {
                    using (StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.UTF8))
                    {
                        result = myStreamReader.ReadToEnd();
                    }
                }
            }

            return result;
        }
    }
}