//GPS坐标转换成火星坐标
var M_PI = 3.14159265358979324;
var a = 6378245.0;
var ee = 0.00669342162296594323;
var x_pi = M_PI * 3000.0 / 180.0;

function wgs2gcj_lat(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 * M_PI) + 20.0 * Math.sin(2.0 * x * M_PI)) * 2.0 / 3.0;
	ret1 += (20.0 * Math.sin(y * M_PI) + 40.0 * Math.sin(y / 3.0 * M_PI)) * 2.0 / 3.0;
	ret1 += (160.0 * Math.sin(y / 12.0 * M_PI) + 320 * Math.sin(y * M_PI / 30.0)) * 2.0 / 3.0;
	return ret1;
}

function wgs2gcj_lng(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 * M_PI) + 20.0 * Math.sin(2.0 * x * M_PI)) * 2.0 / 3.0;
	ret2 += (20.0 * Math.sin(x * M_PI) + 40.0 * Math.sin(x / 3.0 * M_PI)) * 2.0 / 3.0;
	ret2 += (150.0 * Math.sin(x / 12.0 * M_PI) + 300.0 * Math.sin(x / 30.0
			* M_PI)) * 2.0 / 3.0;
	return ret2;
}

function wgs2gcj(lat, lng) {
	var poi2 = {};
	var dLat = wgs2gcj_lat(lng - 105.0, lat - 35.0);
	var dLon = wgs2gcj_lng(lng - 105.0, lat - 35.0);
	var radLat = lat / 180.0 * M_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) * M_PI);
	dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * M_PI);
	poi2.lat = lat + dLat;
	poi2.lng = lng + dLon;
	return poi2;
}

//火星坐标转百度坐标
function gcj2bd(lat, lng) {
	var poi2 = {};
	var x = lng, 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);
	poi2.lng = z * Math.cos(theta) + 0.0065;
	poi2.lat = z * Math.sin(theta) + 0.006;
	return poi2;
}