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- // 大地坐标与经纬度坐标互转
- 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;
- }
- //经纬度=>高斯投影
- 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;
- }
- export default {
- GaussToBL,
- BLToGauss,
- }
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