var gpsBdUtils = function () {

    var pi = 3.14159265358979324;
    var a = 6378245.0;
    var ee = 0.00669342162296594323;
    var x_pi = 3.14159265358979324 * 3000.0 / 180.0;

    function transformLat(lat, lon) {
        var ret = -100.0 + 2.0 * lat + 3.0 * lon + 0.2 * lon * lon + 0.1 * lat * lon + 0.2 * Math.sqrt(Math.abs(lat));
        ret += (20.0 * Math.sin(6.0 * lat * pi) + 20.0 * Math.sin(2.0 * lat * pi)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(lon * pi) + 40.0 * Math.sin(lon / 3.0 * pi)) * 2.0 / 3.0;
        ret += (160.0 * Math.sin(lon / 12.0 * pi) + 320 * Math.sin(lon * pi / 30.0)) * 2.0 / 3.0;
        return ret;
    }

    function transformLon(lat, lon) {
        var ret = 300.0 + lat + 2.0 * lon + 0.1 * lat * lat + 0.1 * lat * lon + 0.1 * Math.sqrt(Math.abs(lat));
        ret += (20.0 * Math.sin(6.0 * lat * pi) + 20.0 * Math.sin(2.0 * lat * pi)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(lat * pi) + 40.0 * Math.sin(lat / 3.0 * pi)) * 2.0 / 3.0;
        ret += (150.0 * Math.sin(lat / 12.0 * pi) + 300.0 * Math.sin(lat / 30.0 * pi)) * 2.0 / 3.0;
        return ret;
    }

    return {
        wgs2bd: function (lat, lon) {//gps转百度坐标
            var wgs2gcj = gpsBdUtils.wgs2gcj(lat, lon);
            var gcj2bd = gpsBdUtils.gcj2bd(wgs2gcj.latitude, wgs2gcj.longitude);
            return gcj2bd;
        },

        gcj2bd: function (lat, lon) {
            var x = lon, y = lat;
            var z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * x_pi);
            var theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * x_pi);
            var bd_lon = z * Math.cos(theta) + 0.0065;
            var bd_lat = z * Math.sin(theta) + 0.006;
            return {"longitude":bd_lon,"latitude":bd_lat};
        },

        bd2gcj: function (lat, lon) {
            var x = lon - 0.0065, y = lat - 0.006;
            var z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * x_pi);
            var theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * x_pi);
            var gg_lon = z * Math.cos(theta);
            var gg_lat = z * Math.sin(theta);
             return {"longitude":gg_lon,"latitude":gg_lat};
        },

        wgs2gcj: function (lat, lon) {
            var dLat = transformLat(lon - 105.0, lat - 35.0);
            var dLon = 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);
            var mgLat = lat + dLat;
            var mgLon = lon + dLon;
            return {"longitude":mgLon,"latitude":mgLat};
        }

    }
}();