Mapbar POI 转 经纬度坐标的各个版本

参考 这个的php和java版本：https://code.google.com/p/freebsd-help/source/browse/Mapbar%E7%BB%8F%E7%BA%AC%E5%9D%90%E6%A0%87%E5%81%8F%E7%A7%BB%E7%9A%84%E5%8A%A0%E8%A7%A3%E5%AF%86%E7%AE%97%E6%B3%95

出来C# 版，后面需要服务端的JAVA版本再贴上来，先上C#版

PHP版本

View Code

 1 function pos_decode($pos) {

 2     $index = -1;

 3     $count = 0;

 4     $code = "";

 5     $len = strlen($pos);

 6     $apiKey = ord($pos[$len - 1]);

 7     $pos = substr($pos, 0, $len - 1);

 8     $len--;

 9     for ($i = 0; $i < $len; $i++) {

10         $hash = intval($pos[$i], 36) - 10;

11         if ($hash >= 10) {

12             $hash = $hash - 7;

13         }

14         $code .= base_convert($hash, 10, 36);

15         if ($hash > $count) {

16             $index = $i;

17             $count = $hash;

18         }

19     }

20     $subLL = intval(substr($code, 0, $index), 16);

21     $addLL = intval(substr($code, $index + 1), 16);

22     $lng = ($subLL + $addLL - intval($apiKey)) / 2;

23     $lat = ($addLL - $lng) / 100000.0;

24     $lng /= 100000.0;

25 

26     return array($lat, $lng);

27 }

JavaScript版本

View Code

 1 function (poi) {

 2         if (DP.isObject(poi)) {

 3             return poi;

 4         };

 5         var _options = this.options,

 6             index = -1,

 7             count = 0,

 8             code = "",

 9             len = poi.length,

10             apiKey = poi.charCodeAt(len - 1),

11             hash,

12             subLL, addLL,

13             lng, lat;

14         poi = poi.substring(0, len - 1);

15         len--;

16         for (var i = 0; i < len; i++) {

17             hash = parseInt(poi.charAt(i), _options.settings.cha) - _options.settings.add;

18             if (hash >= _options.settings.add) {

19                 hash = hash - _options.settings.plus;

20             };

21             code += (hash).toString(_options.settings.cha);

22             if (hash > count) {

23                 index = i;

24                 count = hash;

25             };

26         }

27         subLL = parseInt(code.substring(0, index), _options.settings.digi);

28         addLL = parseInt(code.substring(index + 1), _options.settings.digi);

29         lng = (subLL + addLL - parseInt(apiKey)) / 2;

30         lat = (addLL - lng) / 100000.0;

31         lng /= 100000.0;

32         return { "lat": lat, "lng": lng };

33     }

增加一个C#版本

        static int ConvertToInt32(char c)

        {

            if (c >= 48 && c <= 57) { return c - 48; }

            if (c >= 97 && c <= 122) { return c - 87; }

            if (c >= 65 && c <= 90) { return c - 55; }

            return 0;

        }



        static string ConvertToString(int v, int fromBase)

        {

            if (fromBase < 2 || fromBase > 36) throw new ArgumentException();

            List<char> cs = new List<char>(36);

            while (v > 0)

            {

                int x = v % fromBase;

                int c = 48;

                if (x >= 10) { c = 87; }

                cs.Add((char)(x + c));

                v /= fromBase;

            }

            cs.Reverse();

            string s = new string(cs.ToArray());

            return s;

        }

        private Location Decode(string poi)

        {

            int index = -1;

            int count = 0;

            string code = "";

            int len = poi.Length;

            char apiKey = poi[len - 1];

            int hash = 0;

            int subLL = 0;

            int addLL = 0;

            double lng = 0;

            double lat = 0;

            poi = poi.Substring(0, len - 1);

            len--;

            for (int i = 0; i < len; i++)

            {

                hash = ConvertToInt32(poi[i]) - 10;

                if (hash >= 10)

                {

                    hash = hash - 7;

                }

                code += ConvertToString(hash, 36);

                if (hash > count)

                {

                    index = i;

                    count = hash;

                }

            }

            subLL = Convert.ToInt32(code.Substring(0, index), 16);

            addLL = Convert.ToInt32(code.Substring(index + 1), 16);

            lng = (subLL + addLL - Convert.ToInt32(apiKey + "", 16)) / 2.0d;

            lat = (addLL - lng) / 100000.0d;

            lng /= 100000.0;

            return new Location()

            {

                lat = lat,

                lng = lng

            };

        }

 

Java版本请听下回分解