下面是高斯正算的代码,可以实现BL到54的转换,没有问题,我现在要实现BL到80的转换,我应该怎么改椭球参数呢?
const double PI = Math.PI; //定义圆周率
const double rho = 206264.806247096355;
/// <summary>
/// 高斯正算
/// </summary>
/// <param name="B">纬度(度)</param>
/// <param name="L">经度(度)</param>
/// <param name="num">带号</param>
public double[] CalculateEllipse2plane(double B,double L,double num)
{
AngleCalculate ac = new AngleCalculate(); //用于角度弧度转换
double l,L0,a0,a3,a4,a5,a6,n,c;
l = 0;L0 = 0;a0 = 0;a3 = 0;a4 = 0;a5 = 0;a6 = 0;n = 0;c = 0;
double x,y;
x = 0;y = 0;
double m, p;
m = 0;p = 0;
int N;//带号
N = 0;
//判断带号
if(num == 6)
{
N = (int)L/6;//带号
L0 = 6*N-3;//中央子午线
}
else
{
N = (int)((L+1.5)/3); //3度带号
L0 = 3*N;//3度中央子午线
}
bool sign = true;
l = (L - L0) * 3600/rho; //单位秒
if (l < 0) sign = false;
B = ac.AngleToArc(B);//将纬度化为弧度
L = ac.AngleToArc(L);//将经度化为弧度
L0 = ac.AngleToArc(L0);//将中央子午线转为弧度
l = Math.Pow(l,2);
c = Math.Pow(Math.Cos(B),2); //Cos(B)的平方
//n = 6399596.651988010- (21562.267 - (108.973 - 0.612 * c) * c) * c;
n = 6399698.902-(21562.267-(108.973-0.612 * c)*c)*c;
a0 = 32140.404-(135.3302-(0.7092-0.0040*c)*c)*c;
a3 =(0.3333333+0.001123*c)*c-0.1666667;
a4 = (0.25+0.00252*c)*c-0.04166;
a5=0.0083-(0.1667-(0.1968+0.004*c)*c)*c;
a6=(0.166*c-0.084)*c;
//计算平面坐标并化为国家统一坐标
m=Math.Sin(B)*Math.Cos(B);
p = 1+(a3+a5*l)*l;
x=6367558.4969*B-(a0-(0.5+(a4+a6*l)*l)*l*n)*m;
y=(p)*Math.Sqrt(l)*n*Math.Cos(B);
if (sign)
{
y = y + 500000 + N * 1000000; //加上常数改正,和带号
}
else
{
y = (500000 - y) + N * 1000000; //加上常数改正,和带号
}
double[] CalculateResult = new double[2];
CalculateResult[0] = x;
CalculateResult[1] = y;
return CalculateResult;
}