地球坐标系(WGS-84)转火星坐标系(GCJ)

/**

 * 单点坐标纠偏

 */

var pi = 3.14159265358979324;

var a = 6378245.0;

var ee = 0.00669342162296594323;

var x_pi = 3.14159265358979324 * 3000.0 / 180.0;

/**

 * 地球坐标转换为火星坐标，即WGS84（国际通用）转为GCJ02坐标系

 * 适用于腾讯地图、高德（阿里）地图或谷歌地图

 */

function transform (wgLat, wgLon) {

    var latlng = [];

    if(outOfChina(wgLat, wgLon)) {

        latlng[0] = wgLat;

        latlng[1] = wgLon;

        return latlng;

    }

    var dLat = transformLat(wgLon - 105.0, wgLat - 35.0);

    var dLon = transformLon(wgLon - 105.0, wgLat - 35.0);

    var radLat = wgLat / 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);

    latlng[0] = wgLat + dLat;

    latlng[1] = wgLon + dLon;

    return latlng;

};

function outOfChina(lat, lon) {

    if(lon < 72.004 || lon > 137.8347)

        return true;

    if(lat < 0.8293 || lat > 55.8271)

        return true;

    return false;

};

function transformLat(x, 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;

};

function transformLon(x, 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;

};

/**

 * 地球坐标转换为百度坐标，即GCJ02坐标系转为为BD09坐标系

 * 适用于百度地图

 * @param gg_lat

 * @param gg_lon

 */

function bd_transform (lat, lon) {

    var latlng = this.transform(lat, lon);

    var x = latlng[1],

        y = latlng[0];

    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);

    latlng[0] = z * Math.sin(theta) + 0.006;

    latlng[1] = z * Math.cos(theta) + 0.0065;

    return latlng;

}

地球坐标系(WGS-84)转火星坐标系(GCJ)的相关教程结束。