JS实现WSG(BLH)和空间直角坐标系(XYZ)相互转换

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/**
 * Created by xsg on 2014/6/23.
 */
var pi_180 = Math.PI / 180;
var _180_pi = 180 / Math.PI;
var projectionTypes = {};
projectionTypes.bj54 = {
    a:6378245,//长半轴
    e2:0.006693421622966//第一偏心率平方
};
projectionTypes.wgs84 = {
    a:6378135,//长半轴
    e2:0.00669437999013//第一偏心率平方
};

var myparams = {
    dx : 31.4,
    dy : -144.3,
    dz : -74.8,
    rx : 0,
    ry : 0,
    rz : 0.814,
    m : -0.38
};
//7坐标系统转换方法
//sourceType:源投影类型 targetType：目标投影类型 params： 7参数 blh：源大地坐标
function coordinateTransfUse7params(sourceType,targetType,params,blh){
    sourceType = sourceType.toLowerCase();
    targetType = targetType.toLowerCase();
    var XYZ1 = _BLH2XYZ(sourceType,blh);
    var XYZ2 = _transXYZBy7params(XYZ1,params);
    var blh2 = _XYZ2BLH(targetType,XYZ2);
    console.log(blh2);
}

function _BLH2XYZ(projectionType,blhObj){//将大地坐标喜欢换为空间直角坐标系
    var e2 = projectionTypes[projectionType].e2;//第一偏心率平方值
    var a = projectionTypes[projectionType].a;//长半轴
    var N = a / Math.sqrt(1 - e2 * Math.sin(blhObj.b * pi_180) * Math.sin(blhObj.b * pi_180));
    var X = (N + blhObj.h) * Math.cos(blhObj.b * pi_180) * Math.cos(blhObj.l * pi_180);
    var Y = (N + blhObj.h) * Math.cos(blhObj.b * pi_180) * Math.sin(blhObj.l * pi_180);
    var Z = [N * (1 - e2 ) + blhObj.h] * Math.sin(blhObj.b * pi_180);
    var resultObj = {};
    resultObj.X = X;
    resultObj.Y = Y;
    resultObj.Z = Z;
    return resultObj;
}

function _transXYZBy7params(xyz0,params){//根据7参数对空间直角坐标系进行运算
    var x0 = xyz0.X;
    var y0 = xyz0.Y;
    var z0 = xyz0.Z;
    var dx = params.dx;
    var dy = params.dy;
    var dz = params.dz;
    var rx = params.rx;
    var ry = params.ry;
    var rz = params.rz;
    var m = params.m;
    var x1 = dx + (1 + m) * x0 + Math.sin(rz / 60 / 60 * pi_180) * y0 - Math.sin(ry / 60 / 60 * pi_180) * z0;
    var y1 = dy + (1 + m) * y0 - Math.sin(rz / 60 / 60 * pi_180) * x0 + Math.sin(rx / 60 / 60 * pi_180) * z0;
    var z1 = dz + (1 + m) * z0 + Math.sin(ry / 60 / 60 * pi_180) * x0 - Math.sin(rx / 60 / 60 * pi_180) * y0;
    var resultObj = {};
    resultObj.X = x1;
    resultObj.Y = y1;
    resultObj.Z = z1;
    return resultObj;
}

function _XYZ2BLH(projectionType,xyz1){
    var a = projectionTypes[projectionType].a;
    var e2 = projectionTypes[projectionType].e2;//第一偏心率平方值
    var X = xyz1.X;
    var Y = xyz1.Y;
    var Z = xyz1.Z;
    var L = Math.atan(Y / X) * _180_pi;
    var B = Math.atan(Z / Math.sqrt(X * X + Y * Y));
    while(true){//迭代计算
        var N = a / Math.sqrt(1 - e2 * Math.sin(B) * Math.sin(B));
        var tempB = Math.atan((N  * e2 * Math.sin(B) + Z ) / Math.sqrt(X * X + Y * Y ));
        B = Math.atan((Z + N * e2 * Math.sin(tempB)) / Math.sqrt(X * X + Y * Y ));
        if(tempB == B){
            break;
        }
    }
    var H = Z / Math.sin(B) - N * (1 - e2);
    B = B * _180_pi;
    var resultObj = {};
    resultObj.L = L;
    resultObj.B = B;
    resultObj.H = H;
    if( resultObj.B < 0 ){
        resultObj.B = resultObj.B + 180;
    }
    if(resultObj.L < 0 ){
        resultObj.L = resultObj.L + 180;
    }
    return resultObj;
}

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