Gps坐标转换成火星坐标的两种方法

各个坐标系的概况：请参考：http://blog.csdn.net/findsafety/article/details/12442639

一、坐标转换算法的实现。

    /// <summary>
    /// WGS84坐标转GCJ02坐标
    /// </summary>
　　　public class GDMapChange
    {
        public GDMapChange(float lat, float lon)
        {
            this.latitude = lat;
            this.longitude = lon;
        }
        const double pi = 3.14159265358979324;
        static double a = 6378245.0;
        static double ee = 0.00669342162296594323;
        public double latitude { get; set; }
        public double longitude { get; set; }
        private Boolean outOfChina(double lat, double lon)
        {

            if (lon < 72.004 || lon > 137.8347)
                return true;
            if (lat < 0.8293 || lat > 55.8271)
                return true;
            return false;
        }

        private double transformLat(double x, double y)
        {
            var ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.Sqrt(Math.Abs(x));
            ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
            ret += (20.0 * Math.Sin(y * pi) + 40.0 * Math.Sin(y / 3.0 * pi)) * 2.0 / 3.0;
            ret += (160.0 * Math.Sin(y / 12.0 * pi) + 320 * Math.Sin(y * pi / 30.0)) * 2.0 / 3.0;
            return ret;
        }
        private double transformLon(double x, double y)
        {
            var ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.Sqrt(Math.Abs(x));
            ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
            ret += (20.0 * Math.Sin(x * pi) + 40.0 * Math.Sin(x / 3.0 * pi)) * 2.0 / 3.0;
            ret += (150.0 * Math.Sin(x / 12.0 * pi) + 300.0 * Math.Sin(x / 30.0 * pi)) * 2.0 / 3.0;
            return ret;
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="lat"></param>
        /// <param name="lon"></param>
        /// <returns></returns>
        private GDMapChange delta(float lat, float lon)
        {

            //var a = 6378245.0;
            //var ee = 0.00669342162296594323;
            var dLat = this.transformLat(lon - 105.0, lat - 35.0);
            var dLon = this.transformLon(lon - 105.0, lat - 35.0);
            var radLat = lat / 180.0 * pi;
            var magic = Math.Sin(radLat);
            magic = 1 - ee * magic * magic;
            var sqrtMagic = Math.Sqrt(magic);
            dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
            dLon = (dLon * 180.0) / (a / sqrtMagic * Math.Cos(radLat) * pi);
            GDMapChange gps = new GDMapChange((float)dLat, (float)dLon);
            return gps;
        }

        public GDMapChange gcj_encrypt(float wgsLat, float wgsLon)
        {
            GDMapChange d = this.delta(wgsLat, wgsLon);
            d.latitude = wgsLat + d.latitude;
            d.longitude = wgsLon + d.longitude;
            return d;
        }


    }
 此方法通过算法算出具体偏移量，再与原Gps坐标相加，就是转换之后的坐标结果，经验证，偏差不大。

 二、调用坐标转换接口。（更多的信息详情请查阅GPSspg API）

http://www.gpsspg.com/api/convert/latlng/

#region 偏移处理(将设备上传的GPS坐标转换为火星坐标)
        /// <summary>
        /// 偏移处理
        /// </summary>
        /// <param name="lng">经度</param>
        /// <param name="lat">纬度</param>
        /// <returns></returns>
        public BaiduMapGps GetBaiduMap(float lng, float lat)
        {
            Encoding encoding = Encoding.GetEncoding("UTF-8");
 
             //oid和key 通过申请可以得到 参数说明请看API文档
            string url = "http://api.gpsspg.com/convert/latlng/?oid=yout OID&key=your key&from=0&to=3&latlng=" + lat + "," + lng;

            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
            //也可以是post请求
            request.Method = WebRequestMethods.Http.Get;
            //发送http请求及得到请求响应
            using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
            {
                //使用读取流读取响应结果
                using (StreamReader reader = new StreamReader(response.GetResponseStream()))
                {
                    BaiduMapGps baidumapgps = new BaiduMapGps();
                    string content = reader.ReadToEnd();
                    var jobject = JObject.Parse(content);
                    JArray jarry1 = JArray.Parse(jobject["result"].ToString());
                    for (var k = 0; k < jarry1.Count; k++)
                    {
                        JObject jk = JObject.Parse(jarry1[k].ToString());
                        baidumapgps.y = (float)Convert.ToDecimal(jk["lat"].ToString());
                        baidumapgps.x = (float)Convert.ToDecimal(jk["lng"].ToString());
                    }
                    return baidumapgps;
                }
            }
        }
        #endregion