//坐標正算
lbxy(double l, double b, double *x, double *y, int l0)
{
?double sa,sb,sep,sn,sy2,st,sm,sx,hb;
?double xx,yy,hd,sd;
?//判斷值的范圍
?if (l > 360 || l < 0 || b > 360 || b < 0)
?{
??*x = l;
??*y = b;
??return;
?}
?l? = l-l0;
?sa = 6378245;??
?sb = 6356863.019;
?sep= 0.006738525415;
?hd = b*PI;
?hb = hd/180.0;
?st = tan(hb);
??????
?sn=pow(sa,(double)2)/sqrt(pow(sa,(double)2)*pow(cos(hb),(double)2)
??+pow(sb,(double)2)*pow(sin(hb),(double)2));
?sy2=sep*pow(cos(hb),(double)2);
?sd = cos(hb)*l*PI;
?sm = sd/180.0;
?sx = 111134.861*b-(32005.78*sin(hb)+133.924*pow(sin(hb),(double)3)+0.697*pow(sin(hb),(double)5))*cos(hb);
?xx = sx+sn*st*(0.5*pow(sm,(double)2)+1.0/24.0*(5.0-pow(st,(double)2)+9.0*sy2)*pow(sm,(double)4));
?yy = sn*(sm+1.0/6.0*(1.0-pow(st,(double)2)+sy2)*pow(sm,(double)3)+1.0/120.0*(5.0-18.0*pow(st,(double)2)+pow(st,(double)4))*pow(sm,(double)5));
?*x = xx;
?*y = yy+500000;
}
//坐標反算
xylb(double l0, double x, double y, double *l, double *b)
{
?double bf,vf,nf,ynf,tf,yf2,hbf;
?double sa,sb,se2,sep2,mf;
?double w1,w2,w,w3,w4;
?double pi = 3.1415926;
?x = x/1000000.0;
?y = y - 500000.0;
?
?bf = 9.04353692458*x-0.00001007623*pow(x,2.0)-0.00074438304*pow(x,3.0)-0.00000463064*pow(x,4.0)+0.00000505846*pow(x,5.0)-0.00000016754*pow(x,6.0);
?hbf = bf * pi/ 180.0;
?sa = 6378245.0;
?sb = 6356863.019;
?se2 = 0.006693421623;
?sep2 = 0.006738525415;
?w1 = sin(hbf);
?w2 = 1.0 - se2 * pow(w1,(double)2);
?w = sqrt(w2);
?mf = sa*(1.0-se2)/pow(w,(double)3);
?w3 = cos(hbf);
?w4 = pow(sa,(double)2)*pow(w3,(double)2) + pow(sb,(double)2)*pow(w1,(double)2);
?nf = pow(sa,(double)2) / sqrt(w4);
?ynf = y/nf;
?vf = nf/mf;
?tf = tan(hbf);
?
?yf2 = sep2 * pow(w3, (double)2);
?*b = bf - 1.0/2.0 * vf * tf * (pow(ynf,(double)2)-1.0/12.0*(5.0+3.0*pow(tf,(double)2)+yf2-9.0*yf2*pow(tf,(double)2))*pow(ynf,(double)4))*180.0/pi;
?*l = 1.0/w3*ynf*(1.0-1.0/6.0*(1.0+2.0*pow(tf,(double)2)+yf2)*pow(ynf,(double)2)+1.0/120.0*(5.0+28.0*pow(tf,(double)2)+24.0*pow(tf,(double)2)+6.0*yf2+8.0*yf2*pow(tf,(double)2))*pow(ynf,(double)4))*180.0/pi;
?*l = l0 + *l;
}