【转】GPS经纬度数据转换到以米单位的平面坐标系

以前在网上找的，现在不知道出处是哪里了，呵呵...

转载出来。

  1 //笛卡尔坐标系
  2 typedef struct tagCRDCARTESIAN{
  3 double x;
  4 double y;
  5 double z;
  6 }CRDCARTESIAN,*PCRDCARTESIAN;
  7 //typedef CRDCARTESIAN *PCRDCARTESIAN;
  8 //大地坐标系
  9 typedef struct tagCRDGEODETIC{
 10 double longitude; //经度
 11 double latitude;  //纬度
 12 double height;    //大地高,可设为0
 13 }CRDGEODETIC;
 14 typedef CRDGEODETIC *PCRDGEODETIC;
 15
 16 void CoordCovert::GeodeticToCartesian (PCRDCARTESIAN pcc, PCRDGEODETIC pcg,
 17 double dSemiMajorAxis, double dFlattening)
 18 {
 19     double B;    //纬度度数
 20     double L;    //经度度数
 21     double L0;    //中央经线度数
 22     double l;    //L-L0
 23     double t;    //tanB
 24     double m;    //ltanB
 25     double N;    //卯酉圈曲率半径
 26     double q2;
 27     double x;    //高斯平面纵坐标
 28     double y;    //高斯平面横坐标
 29     double s;    //赤道至纬度B的经线弧长
 30     double f;    //参考椭球体扁率
 31     double e2;    //椭球第一偏心率
 32     double a;    //参考椭球体长半轴
 33     //double b;    //参考椭球体短半轴
 34     double a1;
 35     double a2;
 36     double a3;
 37     double a4;
 38     double b1;
 39     double b2;
 40     double b3;
 41     double b4;
 42     double c0;
 43     double c1;
 44     double c2;
 45     double c3;
 46     int Datum=84;    //投影基准面类型：北京54基准面为54，西安80基准面为80，WGS84基准面为84
 47     int prjno=0;    //投影带号
 48     int zonewide=3;
 49     double IPI=0.0174532925199433333333;    //3.1415926535898/180.0
 50     B=pcg->latitude ; //纬度
 51     L=pcg->longitude ; //经度
 52     if (zonewide==6)
 53     {
 54          prjno=(int)(L/zonewide)+1;
 55          L0=prjno*zonewide-3;
 56     }
 57     else
 58     {
 59         prjno=(int)((L-1.5)/3)+1;
 60         L0=prjno*3;
 61     }
 62
 63     if(Datum==54)
 64     {
 65          a=6378245;
 66          f=1/298.3;
 67     }
 68     else if(Datum==84)
 69     {
 70         a=6378137;
 71         f=1/298.257223563;
 72     }
 73     L0=L0*IPI;
 74     L=L*IPI;
 75     B=B*IPI;
 76     e2=2*f-f*f;//(a*a-b*b)/(a*a);
 77     l=L-L0;
 78     t=tan(B);
 79     m=l * cos(B);
 80     N=a/sqrt(1-e2* sin(B) * sin(B));
 81     q2=e2/(1-e2)* cos(B)* cos(B);
 82     a1=1+(double)3/4*e2+(double)45/64*e2*e2+(double)175/256*e2*e2*e2+(double)11025/16384*e2*e2*e2*e2+(double)43659/65536*e2*e2*e2*e2*e2;
 83     a2=(double)3/4*e2+(double)15/16*e2*e2+(double)525/512*e2*e2*e2+(double)2205/2048*e2*e2*e2*e2+(double)72765/65536*e2*e2*e2*e2*e2;
 84     a3=(double)15/64*e2*e2+(double)105/256*e2*e2*e2+(double)2205/4096*e2*e2*e2*e2+(double)10359/16384*e2*e2*e2*e2*e2;
 85     a4=(double)35/512*e2*e2*e2+(double)315/2048*e2*e2*e2*e2+(double)31185/13072*e2*e2*e2*e2*e2;
 86     b1=a1*a*(1-e2);
 87     b2=(double)-1/2*a2*a*(1-e2);
 88     b3=(double)1/4*a3*a*(1-e2);
 89     b4=(double)-1/6*a4*a*(1-e2);
 90     c0=b1;
 91     c1=2*b2+4*b3+6*b4;
 92     c2=-(8*b3+32*b4);
 93     c3=32*b4;
 94     s=c0*B+cos(B)*(c1*sin(B)+c2*sin(B)*sin(B)*sin(B)+c3*sin(B)*sin(B)*sin(B)*sin(B)*sin(B));
 95     x=s+(double)1/2*N*t*m*m+(double)1/24*(5-t*t+9*q2+4*q2*q2)*N*t*m*m*m*m+(double)1/720*(61-58*t*t+t*t*t*t)*N*t*m*m*m*m*m*m;
 96     y=N*m+(double)1/6*(1-t*t+q2)*N*m*m*m+(double)1/120*(5-18*t*t+t*t*t*t-14*q2-58*q2*t*t)*N*m*m*m*m*m;
 97     y=y+1000000*prjno+500000;
 98     pcc->x=x;
 99     pcc->y=y-38000000;
100     pcc->z=0;
101 }