高斯坐标与经纬度坐标互转

一、高斯投影坐标 转 经纬度

function GaussToBL(X,Y){
    let ProjNo;
    let ZoneWide; 带宽
    let output = new Array(2);
    let longitude1,latitude1, longitude0, X0,Y0, xval,yval;//latitude0,
    let e1,e2,f,a, ee, NN, T,C, M, D,R,u,fai, iPI;
    iPI = 3.14159265358979324/180.0; 3.1415926535898/180.0;
    // a = 6378245.0; f = 1.0/298.3; //54年北京坐标系参数
    a=6378140.0; f=1.0/298.257; //80年西安坐标系参数
    ZoneWide = 6; 6度带宽
    ProjNo = parseInt(X/1000000) ; //查找带号
    longitude0 = (ProjNo-1) * ZoneWide + ZoneWide / 2;
    longitude0 = longitude0 * iPI ; //中央经线


    X0 = ProjNo*1000000+500000;
    Y0 = 0;
    xval = X-X0; yval = Y-Y0; //带内大地坐标
    e2 = 2*f-f*f;
    e1 = (1.0-Math.sqrt(1-e2))/(1.0+Math.sqrt(1-e2));
    ee = e2/(1-e2);
    M = yval;
    u = M/(a*(1-e2/4-3*e2*e2/64-5*e2*e2*e2/256));
    fai = u+(3*e1/2-27*e1*e1*e1/32)*Math.sin(2*u)+(21*e1*e1/16-55*e1*e1*e1*e1/32)*Math.sin(4*u) +(151*e1*e1*e1/96)*
        Math.sin(6*u)+(1097*e1*e1*e1*e1/512)*Math.sin(8*u);
    C = ee*Math.cos(fai)*Math.cos(fai);
    T = Math.tan(fai)*Math.tan(fai);
    NN = a/Math.sqrt(1.0-e2*Math.sin(fai)*Math.sin(fai));
    R = a*(1-e2)/Math.sqrt((1-e2*Math.sin(fai)*Math.sin(fai))*(1-e2*Math.sin(fai)*Math.sin(fai))*(1-e2*Math.sin
    (fai)*Math.sin(fai)));
    D = xval/NN;
    //计算经度(Longitude) 纬度(Latitude)
    longitude1 = longitude0+(D-(1+2*T+C)*D*D*D/6+(5-2*C+28*T-3*C*C+8*ee+24*T*T)*D
        *D*D*D*D/120)/Math.cos(fai);
    latitude1 = fai -(NN*Math.tan(fai)/R)*(D*D/2-(5+3*T+10*C-4*C*C-9*ee)*D*D*D*D/24
        +(61+90*T+298*C+45*T*T-256*ee-3*C*C)*D*D*D*D*D*D/720);
    //转换为度 DD
    output[0] = longitude1 / iPI;
    output[1] = latitude1 / iPI;
    return output;
}

二、经纬度 转 高斯投影坐标

function BLToGauss(longitude, latitude){
    let ProjNo=0;
    let ZoneWide; 带宽
    let ret=Array(2);
    let longitude1,latitude1, longitude0,latitude0, X0,Y0, xval,yval;
    let a,f, e2,ee, NN, T,C,A, M, iPI;
    iPI = 0.0174532925199433; 3.1415926535898/180.0;
    ZoneWide = 6; 6度带宽
    // a=6378245.0; f=1.0/298.3; //54年北京坐标系参数
    a=6378140.0; f=1/298.257; //80年西安坐标系参数
    ProjNo = parseInt(longitude / ZoneWide) ;
    longitude0 = ProjNo * ZoneWide + ZoneWide / 2;
    longitude0 = longitude0 * iPI ;
    latitude0 = 0;
    longitude1 = longitude * iPI ; //经度转换为弧度
    latitude1 = latitude * iPI ; //纬度转换为弧度
    e2=2*f-f*f;
    ee=e2*(1.0-e2);
    NN=a/Math.sqrt(1.0-e2*Math.sin(latitude1)*Math.sin(latitude1));
    T=Math.tan(latitude1)*Math.tan(latitude1);
    C=ee*Math.cos(latitude1)*Math.cos(latitude1);
    A=(longitude1-longitude0)*Math.cos(latitude1);
    M=a*((1-e2/4-3*e2*e2/64-5*e2*e2*e2/256)*latitude1-(3*e2/8+3*e2*e2/32+45*e2*e2
        *e2/1024)*Math.sin(2*latitude1)
        +(15*e2*e2/256+45*e2*e2*e2/1024)*Math.sin(4*latitude1)-(35*e2*e2*e2/3072)*Math.sin(6*latitude1));
    xval = NN*(A+(1-T+C)*A*A*A/6+(5-18*T+T*T+72*C-58*ee)*A*A*A*A*A/120);
    yval = M+NN*Math.tan(latitude1)*(A*A/2+(5-T+9*C+4*C*C)*A*A*A*A/24
        +(61-58*T+T*T+600*C-330*ee)*A*A*A*A*A*A/720);
    X0 = 1000000*(ProjNo+1)+500000;
    Y0 = 0;
    xval = xval+X0; yval = yval+Y0;
    ret[0]=xval;
    ret[1]=yval;

    return ret;
}