# 不同地图坐标系的经纬度转换方法

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

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;
};

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

/*
* BD-09：百度坐标偏移标准，Baidu Map使用
*/

/**
* wgLat 纬度
* wgLon 经度
* WGS-84 到 GCJ-02 的转换（即 GPS 加偏）
* */
function wgs_gcj_encrypts(wgLat, wgLon) {
var point={};
if (outOfChina(wgLat, wgLon)) {
point.lat=wgLat;
point.lng=wgLon;
return point;
}
var dLat = transformLat(wgLon - 105.0, wgLat - 35.0);
var dLon = transformLon(wgLon - 105.0, wgLat - 35.0);
var radLat = wgLat / 180.0 * pi;
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 lat = wgLat + dLat;
var lon = wgLon + dLon;
point.lat=lat;
point.lon=lon;
return point;
};

/**
* wgLat 纬度
* wgLon 经度
* BD-09转换GCJ-02
* */
var point={};
var x = bd_lon - 0.0065;
var y = bd_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);
point.lat=gg_lat;
point.lon=gg_lon;
return point;
};

/**
* gg_lat 纬度
* gg_lon 经度
* GCJ-02转换BD-09
* */
var point={};
var x = gg_lon;
var y = gg_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;
point.lat=bd_lat;
point.lon=bd_lon;
return point;
};


posted @ 2016-08-13 15:19  赵小生z  阅读(6705)  评论(0编辑  收藏  举报