gps坐标转换百度坐标本地化

百度地图API中的坐标转换一次最多支持10个坐标，如果坐标量太大页面加载缓慢。

解决方案：本地转换

/**
* 坐标系转换函数
* WGS->GCJ
* WGS->BD09
* GCJ->BD09
*/
function Convertor(ak) {
this.stepCount = 100;
this.pointCount = [];
this.Result = [];
this.NoisIndex = [];
this.Time = new Date();
this.AK = ak;
this.M_PI = 3.14159265358979324;
this.A = 6378245.0;
this.EE = 0.00669342162296594323;
this.X_PI = this.M_PI * 3000.0 / 180.0;
}
Convertor.prototype.outofChine = function(p) {
if (p.lng < 72.004 || p.lng > 137.8347) {
return true;
}
if (p.lat < 0.8293 || p.lat > 55.8271) {
return true;
}
return false;
}
;
Convertor.prototype.WGS2GCJ_lat = function(x, y) {
var ret1 = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
ret1 += (20.0 * Math.sin(6.0 * x * this.M_PI) + 20.0 * Math.sin(2.0 * x * this.M_PI)) * 2.0 / 3.0;
ret1 += (20.0 * Math.sin(y * this.M_PI) + 40.0 * Math.sin(y / 3.0 * this.M_PI)) * 2.0 / 3.0;
ret1 += (160.0 * Math.sin(y / 12.0 * this.M_PI) + 320 * Math.sin(y * this.M_PI / 30.0)) * 2.0 / 3.0;
return ret1;
}
;
Convertor.prototype.WGS2GCJ_lng = function(x, y) {
var ret2 = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
ret2 += (20.0 * Math.sin(6.0 * x * this.M_PI) + 20.0 * Math.sin(2.0 * x * this.M_PI)) * 2.0 / 3.0;
ret2 += (20.0 * Math.sin(x * this.M_PI) + 40.0 * Math.sin(x / 3.0 * this.M_PI)) * 2.0 / 3.0;
ret2 += (150.0 * Math.sin(x / 12.0 * this.M_PI) + 300.0 * Math.sin(x / 30.0 * this.M_PI)) * 2.0 / 3.0;
return ret2;
}
;
Convertor.prototype.WGS2GCJ = function(poi) {
if (this.outofChine(poi)) {
return;
}
var poi2 = {};
var dLat = this.WGS2GCJ_lat(poi.lng - 105.0, poi.lat - 35.0);
var dLon = this.WGS2GCJ_lng(poi.lng - 105.0, poi.lat - 35.0);
var radLat = poi.lat / 180.0 * this.M_PI;
var magic = Math.sin(radLat);
magic = 1 - this.EE * magic * magic;
var sqrtMagic = Math.sqrt(magic);
dLat = (dLat * 180.0) / ((this.A * (1 - this.EE)) / (magic * sqrtMagic) * this.M_PI);
dLon = (dLon * 180.0) / (this.A / sqrtMagic * Math.cos(radLat) * this.M_PI);
poi2.lat = poi.lat + dLat;
poi2.lng = poi.lng + dLon;
return poi2;
}
;
Convertor.prototype.GCJ2BD09 = function(poi) {
var poi2 = {};
var x = poi.lng
, y = poi.lat;
var z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * this.X_PI);
var theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * this.X_PI);
poi2.lng = z * Math.cos(theta) + 0.0065;
poi2.lat = z * Math.sin(theta) + 0.006;
return poi2;
}
;
/**
* WGS->百度坐标系
*/
Convertor.prototype.WGS2BD09 = function(poi) {
//WGS->GCJ
var poi2 = this.WGS2GCJ(poi);
if (typeof poi2 === "undefined") {
return;
}
//GCJ->百度坐标系
return this.GCJ2BD09(poi2);
}

var cc = new Convertor();
var gps = cc.WGS2BD09({lng:123,lat:38});

console.log(gps);