由于最近在开发相关地图应用,所以不可必免的就会遇到GPS坐标(WGS-84)转换成国家测绘局标准要求的GCJ-02(所谓的火星坐标)
关于WGS-84与GCJ-02可以参照这篇文章,坐标转换、偏移.
下面的代码摘直网上,特收藏下
//World Geodetic System ==> Mars Geodetic System
//translate from https://on4wp7.codeplex.com/SourceControl/changeset/view/21483#353936
var WGS84_to_GCJ02 = function() {}
WGS84_to_GCJ02.prototype.a = 6378245.0;
WGS84_to_GCJ02.prototype.ee = 0.00669342162296594323;
WGS84_to_GCJ02.prototype.transform = function(wgLat, wgLon) {
if (this.outOfChina(wgLat, wgLon)) {
return [wgLat, wgLon];
}
dLat = this.transformLat(wgLon - 105.0, wgLat - 35.0);
dLon = this.transformLon(wgLon - 105.0, wgLat - 35.0);
radLat = wgLat / 180.0 * Math.PI;
magic = Math.sin(radLat);
magic = 1 - this.ee * magic * magic;
sqrtMagic = Math.sqrt(magic);
dLat = (dLat * 180.0) / ((this.a * (1 - this.ee)) / (magic * sqrtMagic) * Math.PI);
dLon = (dLon * 180.0) / (this.a / sqrtMagic * Math.cos(radLat) * Math.PI);
mgLat = wgLat + dLat;
mgLon = wgLon + dLon;
return [mgLat, mgLon];
};
WGS84_to_GCJ02.prototype.outOfChina = function(lat, lon) {
if (lon < 72.004 || lon > 137.8347)
return true;
if (lat < 0.8293 || lat > 55.8271)
return true;
return false;
};
WGS84_to_GCJ02.prototype.transformLat = function(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 * Math.PI) + 20.0 * Math.sin(2.0 * x * Math.PI)) * 2.0 / 3.0;
ret += (20.0 * Math.sin(y * Math.PI) + 40.0 * Math.sin(y / 3.0 * Math.PI)) * 2.0 / 3.0;
ret += (160.0 * Math.sin(y / 12.0 * Math.PI) + 320 * Math.sin(y * Math.PI / 30.0)) * 2.0 / 3.0;
return ret;
};
WGS84_to_GCJ02.prototype.transformLon = function(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 * Math.PI) + 20.0 * Math.sin(2.0 * x * Math.PI)) * 2.0 / 3.0;
ret += (20.0 * Math.sin(x * Math.PI) + 40.0 * Math.sin(x / 3.0 * Math.PI)) * 2.0 / 3.0;
ret += (150.0 * Math.sin(x / 12.0 * Math.PI) + 300.0 * Math.sin(x / 30.0 * Math.PI)) * 2.0 / 3.0;
return ret;
};
使用例子如下:
new WGS84_to_GCJ02().transform(31.283814, 121.502191)
// -> [31.28181188043995, 121.50661885748906] （该坐标是上海同济大学）
最后附上一个在线转换接口,在线转换坐标接口
