/// <summary>
/// 计算归化纬度
/// </summary>
/// <param name="B1">大地纬度</param>
/// <param name="sinu1">归化纬度sin</param>
/// <param name="cosu1">归化纬度cos</param>
private void CalReducedLat(double B1, ref double sinu1, ref double cosu1)
{
double e1 = Ell.e1;
double W1 = GeoPro.GetW(e1, B1);
sinu1 = Math.Sqrt(1 - e1 * e1) / W1 * Math.Sin(B1);
cosu1 = Math.Cos(B1) / W1;
}
public static StringBuilder GetReport(Ellipsoid ellipsoid, List <GeodesicInfo> data, int type)
{
StringBuilder sb = new StringBuilder();
string line;
line = "**********************************************************************\r\n\r\n";
sb.Append(line);
line = "\t\t\t\t大地主题解算报告\r\n\r\n";
sb.Append(line);
line = "**********************************************************************\r\n\r\n\r\n";
sb.Append(line);
line = "------------------------------统计数据---------------------------------\r\n\r\n";
sb.Append(line);
line = "\t计算点对总数：".PadRight(20) + data.Count + "\r\n\r\n";
sb.Append(line);
line = "\t椭球长半轴：".PadRight(20) + ellipsoid.a + "\r\n\r\n";
sb.Append(line);
line = "\t椭球扁率：".PadRight(20) + ellipsoid.f + "\r\n\r\n";
sb.Append(line);
if (type == 1)
{
line = "\t计算类型：".PadRight(20) + "大地主题正算\t\r\n\r\n";
}
else
{
line = "\t计算类型：".PadRight(20) + "大地主题反算\t\r\n\r";
}
sb.Append(line);
line = "\n\n";
sb.Append(line);
line = "------------------------------计算结果--------------------------------------\r\n\r\n";
sb.Append(line);
line = "\t点名\t纬度（B）\t\t经度 （L）\t\t大地方位角（A）\t\t大地线（S）\r\n\r\n";
sb.Append(line);
for (int i = 0; i < data.Count; i++)
{
GeodesicInfo info = data[i];
Pointinfo p1 = info.P1;
Pointinfo p2 = info.P2;
line = "\n";
sb.Append(line);
line = "\t" + p1.Name.PadRight(10) + GeoPro.DMS2String(p1.B).PadRight(15) + GeoPro.DMS2String(p1.L).PadRight(15) + GeoPro.DMS2String(info.A12).PadRight(15) + info.S.ToString("0.000") + "\t\t\r\n\r\n";
sb.Append(line);
line = "\t" + p2.Name.PadRight(10) + GeoPro.DMS2String(p2.B).PadRight(15) + GeoPro.DMS2String(p2.L).PadRight(15) + GeoPro.DMS2String(info.A21).PadRight(15) + info.S.ToString("0.000") + "\t\t\r\n\r\n";
sb.Append(line);
}
line = "\n";
sb.Append(line);
return(sb);
}
private void UpdateNegTable()
{
DataRow dr;
for (int i = 0; i < NegData.Count; i++)
{
GeodesicInfo data = NegData[i];
dr = NegDataTable.Rows[i];
dr["A1"] = GeoPro.DMS2String(data.A12);
dr["A2"] = GeoPro.DMS2String(data.A21);
dr["S"] = data.S.ToString("0.000");
}
}
/// <summary>
/// 计算A,B,C等参数
/// </summary>
/// <param name="sinA0">sinA0</param>
/// <param name="ABC">ABC数组</param>
/// <param name="alpha">alpha</param>
/// <param name="beta">beta</param>
private void CalABC_AlphaBeta(double sinA0, double[] ABC, ref double alpha, ref double beta, ref double gama)
{
double cos2_A0 = 1 - sinA0 * sinA0;
double k_2 = 0;
double e2 = Ell.e2, b = Ell.b;
double e1 = Ell.e1;
k_2 = GeoPro.Getk_2(e2, cos2_A0);
GeoPro.GetABC(b, k_2, ABC);
alpha = GeoPro.GetAlpha(e1, cos2_A0);
beta = GeoPro.GetBeta(e1, cos2_A0);
gama = GeoPro.GetGama(e1, cos2_A0);
}
private void UpdatePosTable()
{
DataRow dr;
for (int i = 0; i < PosData.Count; i++)
{
GeodesicInfo data = PosData[i];
dr = PosDataTable.Rows[i];
Pointinfo p2 = data.P2;
dr["终点"] = p2.Name;
dr["B2"] = GeoPro.DMS2String(p2.B);
dr["L2"] = GeoPro.DMS2String(p2.L);
dr["A2"] = GeoPro.DMS2String(data.A21);
}
}
private void NegData2Table()
{
NegDataTable = new DataTable();
NegDataTable.Columns.Add("起点", System.Type.GetType("System.String"));
NegDataTable.Columns.Add("B1", System.Type.GetType("System.String"));
NegDataTable.Columns.Add("L1", System.Type.GetType("System.String"));
NegDataTable.Columns.Add("终点", System.Type.GetType("System.String"));
NegDataTable.Columns.Add("B2", System.Type.GetType("System.String"));
NegDataTable.Columns.Add("L2", System.Type.GetType("System.String"));
NegDataTable.Columns.Add("A1", System.Type.GetType("System.String"));
NegDataTable.Columns.Add("A2", System.Type.GetType("System.String"));
NegDataTable.Columns.Add("S", System.Type.GetType("System.String"));
DataRow dr;
for (int i = 0; i < NegData.Count; i++)
{
GeodesicInfo data = NegData[i];
Pointinfo p1 = data.P1;
Pointinfo p2 = data.P2;
dr = NegDataTable.NewRow();
dr["起点"] = p1.Name;
dr["B1"] = GeoPro.DMS2String(p1.B);
dr["L1"] = GeoPro.DMS2String(p1.L);
dr["终点"] = p2.Name;
dr["B2"] = GeoPro.DMS2String(p2.B);
dr["L2"] = GeoPro.DMS2String(p2.L);
NegDataTable.Rows.Add(dr);
}
EllipsoidA.Text = "椭球长半轴（a）：" + MyEllipsoid.a;
Ellipsoidf_.Text = "椭球扁率（f）：" + MyEllipsoid.f;
dataGridViewNeg.DataSource = NegDataTable;
for (int i = 0; i < dataGridViewNeg.ColumnCount; i++)
{
dataGridViewNeg.Columns[i].SortMode = DataGridViewColumnSortMode.NotSortable;
}
}
private void PosData2Table()
{
PosDataTable = new DataTable();
PosDataTable.Columns.Add("起点", System.Type.GetType("System.String"));
PosDataTable.Columns.Add("B1", System.Type.GetType("System.String"));
PosDataTable.Columns.Add("L1", System.Type.GetType("System.String"));
PosDataTable.Columns.Add("A1", System.Type.GetType("System.String"));
PosDataTable.Columns.Add("S", System.Type.GetType("System.String"));
PosDataTable.Columns.Add("终点", System.Type.GetType("System.String"));
PosDataTable.Columns.Add("B2", System.Type.GetType("System.String"));
PosDataTable.Columns.Add("L2", System.Type.GetType("System.String"));
PosDataTable.Columns.Add("A2", System.Type.GetType("System.String"));
DataRow dr;
for (int i = 0; i < PosData.Count; i++)
{
GeodesicInfo data = PosData[i];
Pointinfo p1 = data.P1;
dr = PosDataTable.NewRow();
dr["起点"] = p1.Name;
dr["B1"] = GeoPro.DMS2String(p1.B);
dr["L1"] = GeoPro.DMS2String(p1.L);
dr["A1"] = GeoPro.DMS2String(data.A12);
dr["S"] = data.S.ToString("0.000");
PosDataTable.Rows.Add(dr);
}
dataGridViewPos.DataSource = PosDataTable;
for (int i = 0; i < dataGridViewPos.ColumnCount; i++)
{
dataGridViewPos.Columns[i].SortMode = DataGridViewColumnSortMode.NotSortable;
}
EllipsoidA.Text = "椭球长半轴（a）：" + MyEllipsoid.a;
Ellipsoidf_.Text = "椭球扁率（f）：" + MyEllipsoid.f;
}
/// <summary>
/// 趋近法算角度
/// </summary>
/// <param name="dL">初始经度差</param>
/// <param name="cosu2">cosu2</param>
/// <param name="cosu1">cosu1</param>
/// <param name="ab">ab参数数组</param>
/// <param name="lamda">lamda经度差估计值</param>
/// <param name="A1">A1坐标方位角</param>
/// <param name="del">del</param>
/// <param name="cos2_A0">cos2_A0</param>
/// <param name="x">x</param>
private void CalA1_Lamda(double dL, double u2, double u1, double [] ab, ref double lamda, ref double A1,
ref double del, ref double cos2_A0)
{
double deltat = 0, delta = 0;
double cos_del = 0, sin_del = 0;
double e1 = Ell.e1;
double alpha = 0, beta = 0, gama = 0;
double sinA0;
double p = 0;
double q = 0;
lamda = dL;
do
{
deltat = delta;
p = Math.Cos(u2) * Math.Sin(lamda);
q = ab[2] - ab[3] * Math.Cos(lamda);
A1 = Math.Abs(Math.Atan(p / q));
A1 = GeoPro.InvJudgeA1A2(p, q, A1);
sin_del = p * Math.Sin(A1) + q * Math.Cos(A1);
cos_del = ab[0] + ab[1] * Math.Cos(lamda);
del = Math.Atan(sin_del / cos_del);
del = GeoPro.InvJudgedel(del, cos_del);
sinA0 = Math.Cos(u1) * Math.Sin(A1);
double del1 = Math.Atan(Math.Tan(u1) / Math.Cos(A1));
cos2_A0 = 1 - sinA0 * sinA0;
alpha = GeoPro.GetAlpha(e1, cos2_A0);
beta = GeoPro.GetBeta(e1, cos2_A0);
gama = GeoPro.GetGama(e1, cos2_A0);
delta = (alpha * del + (beta) * Math.Cos(2 * del1 + del) * Math.Sin(del)
+ gama * Math.Sin(2 * del) * Math.Cos(4 * del1 + 2 * del)) * sinA0;
lamda = dL + delta;
} while (Math.Abs(delta - deltat) * 206265 > 0.00001);
}
public void Invertest(GeodesicInfo geodesic)
{
//数据格式转换
double B1 = GeoPro.DMS2RAD(geodesic.P1.B);
double L1 = GeoPro.DMS2RAD(geodesic.P1.L);
double B2 = GeoPro.DMS2RAD(geodesic.P2.B);
double L2 = GeoPro.DMS2RAD(geodesic.P2.L);
double A12 = 0, A21 = 0, S = 0;
//椭球参数
double eps, e2, a, b;
eps = Ell.e2 * Ell.e2; e2 = Ell.e1 * Ell.e1;
a = Ell.a; b = Ell.b;
double u1 = Math.Atan(Math.Sqrt(1 - e2) * Math.Tan(B1));
double u2 = Math.Atan(Math.Sqrt(1 - e2) * Math.Tan(B2));
double DL = L2 - L1;
double sa1 = Math.Sin(u1) * Math.Sin(u2);
double sa2 = Math.Cos(u1) * Math.Cos(u2);
double cb1 = Math.Cos(u1) * Math.Sin(u2);
double cb2 = Math.Sin(u1) * Math.Cos(u2);
double lambda = DL;
// '-------特殊情况点位判断----------------
if (u1 == 0 && u2 == 0)
{
if (lambda > 0)
{
S = a * lambda;
A12 = Math.PI / 2;
A21 = Math.PI * 3 / 2;
}
else
{
S = a * lambda;
A21 = Math.PI / 2;
A12 = Math.PI * 3 / 2;
}
}
else
{
double Dlambda = 0;
double sinA0 = 0; double sigma = 0; double sigma1 = 0;
do
{
double lambda0 = lambda;
double p = Math.Cos(u2) * Math.Sin(lambda0);
double q = cb1 - cb2 * Math.Cos(lambda0);
A12 = Math.Abs(Math.Atan(p / q));
if (p > 0 && q > 0)
{
A12 = A12;
}
if (p > 0 && q < 0)
{
A12 = Math.PI - A12;
}
if (p < 0 && q < 0)
{
A12 = Math.PI + A12;
}
if (p < 0 && q > 0)
{
A12 = 2 * Math.PI - A12;
}
double Ssigma = p * Math.Sin(A12) + q * Math.Cos(A12);
double csigma = sa1 + sa2 * Math.Cos(lambda0);
sigma = Math.Abs(Math.Atan(Ssigma / csigma));
if (csigma > 0)
{
sigma = sigma;
}
if (csigma < 0)
{
sigma = Math.PI - sigma;
}
sinA0 = Math.Cos(u1) * Math.Sin(A12);
sigma1 = Math.Atan(Math.Tan(u1) / Math.Cos(A12));
double cosA0 = Math.Sqrt(1 - sinA0 * sinA0);
double e4 = e2 * e2;
double e6 = e4 * e2;
double xk2 = e2 * cosA0 * cosA0;
double xk4 = xk2 * xk2;
double xk6 = xk4 * xk2;
double alpha1 = (e2 / 2 + e4 / 8 + e6 / 16) - e2 * (1 + e2) * xk2 / 16 + 3 * xk4 * e2 / 128;
double beta1 = e2 * (1 + e2) * xk2 / 16 - e2 * xk4 / 32;
double gamma1 = e2 * xk4 / 256;
double xxy = alpha1 * sigma + beta1 * Math.Sin(sigma) * Math.Cos(2 * sigma1 + sigma);
xxy = xxy + gamma1 * Math.Sin(2 * sigma) * Math.Cos(4 * sigma1 + 2 * sigma);
lambda = DL + sinA0 * xxy;
Dlambda = Math.Abs(lambda - lambda0) * 206265;
} while (Dlambda > 0.000001);
double cosA00 = Math.Sqrt(1 - sinA0 * sinA0);
double xk20 = eps * cosA00 * cosA00;
double xk40 = xk20 * xk20;
double xk60 = xk20 * xk40;
double alpha = (1 - xk20 / 4 + 7 * xk40 / 64 - 15 * xk60 / 256) / b;
double beta = xk20 / 4 - xk40 / 8 + 37 * xk60 / 512;
double gamma = xk40 / 128 - xk60 / 128;
double xs12 = gamma * Math.Sin(2 * sigma) * Math.Cos(4 * sigma1 + 2 * sigma);
S = (sigma - beta * Math.Sin(sigma) * Math.Cos(2 * sigma1 + sigma) - xs12) / alpha;
double sinA2 = Math.Cos(u1) * Math.Sin(A12);
double cosA2 = Math.Cos(u1) * Math.Cos(sigma) * Math.Cos(A12) - Math.Sin(u1) * Math.Sin(sigma);
double tanA2 = sinA2 / cosA2;
A21 = Math.Abs(Math.Atan(sinA2 / cosA2));
double sinA1 = Math.Sin(A12);
if (sinA2 > 0 && cosA2 > 0)
{
A21 = A21;
}
if (sinA2 > 0 && cosA2 < 0)
{
A21 = Math.PI - A21;
}
if (sinA2 < 0 && cosA2 < 0)
{
A21 = Math.PI + A21;
}
if (sinA2 < 0 && cosA2 > 0)
{
A21 = 2 * Math.PI - A21;
}
}
geodesic.A12 = GeoPro.RAD2DMS(A12);
geodesic.A21 = GeoPro.RAD2DMS(A21);
geodesic.S = S;
}
/// <summary>
/// 单组数据反算
/// </summary>
/// <param name="geodesic">单组大地线数据</param>
public void InverseSolution(GeodesicInfo geodesic)
{
//数据格式转换
double B1 = GeoPro.DMS2RAD(geodesic.P1.B);
double L1 = GeoPro.DMS2RAD(geodesic.P1.L);
double B2 = GeoPro.DMS2RAD(geodesic.P2.B);
double L2 = GeoPro.DMS2RAD(geodesic.P2.L);
double A12 = 0, A21 = 0, S = 0;
//椭球参数
double e1, e2, b, c, a;
e1 = Ell.e1; e2 = Ell.e2;
b = Ell.b; c = Ell.c; a = Ell.a;
//辅助计算
double u1 = Math.Atan(Math.Sqrt(1 - e1 * e1) * Math.Tan(B1));
double u2 = Math.Atan(Math.Sqrt(1 - e1 * e1) * Math.Tan(B2));
double dL = L2 - L1;
double[] ab = CalPara(u1, u2);
if (u1 == 0 && u2 == 0)
{
if (dL > 0)
{
S = a * dL;
A12 = Math.PI / 2;
A21 = Math.PI * 3 / 2;
}
else
{
S = a * dL;
A21 = Math.PI / 2;
A12 = Math.PI * 3 / 2;
}
}
else
{
//逐次趋近法同时计算起点大地方位角，球面长度及经度差lamda
double del = 0;
double lamda = 0;
double cos2_A0 = 0;
CalA1_Lamda(dL, u2, u1, ab, ref lamda, ref A12, ref del, ref cos2_A0);
//计算S
double[] ABC = new double[3];
double k_2 = GeoPro.Getk_2(e2, cos2_A0);
GeoPro.GetABC(b, k_2, ABC);
double del1 = Math.Atan(Math.Tan(u1) / Math.Cos(A12));
double xs12 = ABC[2] * Math.Sin(2 * del) * Math.Cos(4 * del1 + 2 * del);
S = (del - ABC[1] * Math.Sin(del) * Math.Cos(2 * del1 + del) - xs12) / ABC[0];
//计算A2
A21 = Math.Atan(Math.Cos(u1) * Math.Sin(lamda) / (ab[2] * Math.Cos(lamda) - ab[3]));
A21 = GeoPro.InvJudgeA1A2(Math.Cos(u1) * Math.Sin(lamda), (ab[2] * Math.Cos(lamda) - ab[3]), A21);
//
if (A12 >= Math.PI)
{
A21 = A21 - Math.PI;
}
if (A12 < Math.PI)
{
A21 = A21 + Math.PI;
}
}
//
geodesic.A12 = GeoPro.RAD2DMS(A12);
geodesic.A21 = GeoPro.RAD2DMS(A21);
geodesic.S = S;
}
/// <summary>
/// 单组数据正算
/// </summary>
/// <param name="geodesic">单组大地线数据</param>
public void DirectSolution(GeodesicInfo geodesic)
{
//数据格式转换
double B1 = GeoPro.DMS2RAD(geodesic.P1.B);
double L1 = GeoPro.DMS2RAD(geodesic.P1.L);
double A12 = GeoPro.DMS2RAD(geodesic.A12);
double S = geodesic.S;
//椭球参数
double e1, e2, b, c;
e1 = Ell.e1; e2 = Ell.e2;
b = Ell.b; c = Ell.c;
//计算归化纬度
double sinu1 = 0, cosu1 = 0;
CalReducedLat(B1, ref sinu1, ref cosu1);
//计算辅助函数，解球面三角
double sinA0 = cosu1 * Math.Sin(A12);
double cot_delta1 = cosu1 * Math.Cos(A12) / sinu1;
double delta1 = Math.Atan(1.0 / cot_delta1);
//计算ABC及α和β
double[] ABC = new double[3];
double alpha = 0;
double beta = 0;
double gama = 0;
CalABC_AlphaBeta(sinA0, ABC, ref alpha, ref beta, ref gama);
//计算球面长度
double delta = ABC[0] * S;
CalGeodesicLength(delta1, ABC, S, ref delta);
//计算经差改正数
double lamda_L = sinA0 * (alpha * delta + beta * Math.Sin(delta) * Math.Cos(2 * delta1 + delta)
+ gama * Math.Sin(2 * delta) * Math.Cos(4 * delta1 + 2 * delta));
//计算终点大地坐标及大地方位角
double sinu2 = sinu1 * Math.Cos(delta) + cosu1 * Math.Cos(A12) * Math.Sin(delta);
double B2 = Math.Atan(1 / Math.Sqrt(1 - e1 * e1) * sinu2 / Math.Sqrt(1 - sinu2 * sinu2));
double lamba = Math.Atan(Math.Sin(delta) * Math.Sin(A12) / (cosu1 * Math.Cos(delta) - sinu1 * Math.Sin(delta)
* Math.Cos(A12)));
lamba = GeoPro.DirJudgelamba(Math.Sin(A12), lamba);
double L2 = L1 + lamba - lamda_L;
double A21 = Math.Atan(cosu1 * Math.Sin(A12) / (cosu1 * Math.Cos(delta)
* Math.Cos(A12) - sinu1 * Math.Sin(delta)));
A21 = GeoPro.DirJudgeA2(Math.Sin(A12), A21);
if (A21 > 2 * Math.PI)
{
A21 -= 2 * Math.PI;
}
if (A21 < 0)
{
A21 += 2 * Math.PI;
}
//角度转换
if (A12 >= Math.PI && A21 >= Math.PI)
{
A21 = A21 - Math.PI;
}
if (A12 < Math.PI && A21 < Math.PI)
{
A21 = A21 + Math.PI;
}
//
// geodesic.P2 = new Pointinfo();
geodesic.P2.B = GeoPro.RAD2DMS(B2);
geodesic.P2.L = GeoPro.RAD2DMS(L2);
geodesic.A21 = GeoPro.RAD2DMS(A21);
}
private void Dirtest(GeodesicInfo geodesic)
{
//数据格式转换
double B1 = GeoPro.DMS2RAD(geodesic.P1.B);
double L1 = GeoPro.DMS2RAD(geodesic.P1.L);
double A12 = GeoPro.DMS2RAD(geodesic.A12);
double S = geodesic.S;
//椭球参数
double eps, e2, b, c, a;
eps = Ell.e2 * Ell.e2; e2 = Ell.e1 * Ell.e1;
b = Ell.b; c = Ell.c; a = Ell.a;
double u1 = Math.Atan(Math.Sqrt(1 - e2) * Math.Tan(B1));
double sinA0 = Math.Cos(u1) * Math.Sin(A12);
double cosA0 = Math.Sqrt(1 - sinA0 * sinA0);
double sigma1 = Math.Atan(Math.Tan(u1) / Math.Cos(A12));
double xk2 = eps * cosA0 * cosA0;
double xk4 = xk2 * xk2;
double xk6 = xk4 * xk2;
double alpha = (1 - xk2 / 4 + 7 * xk4 / 64 - 15 * xk6 / 256) / b;
double beta = xk2 / 4 - xk4 / 8 + 37 * xk6 / 512;
double gamma = xk4 / 128 - xk6 / 128;
double sigma = alpha * S;
double Dsigma = 0;
do
{
double sigma0 = sigma;
sigma = alpha * S + beta * Math.Sin(sigma0) * Math.Cos(2 * sigma1 + sigma0);
sigma = sigma + gamma * Math.Sin(2 * sigma0) * Math.Cos(4 * sigma1 + 2 * sigma0);
Dsigma = Math.Abs(sigma - sigma0) * 206265;
} while (Dsigma > 0.0001);
double sinA2 = Math.Cos(u1) * Math.Sin(A12);
double cosA2 = Math.Cos(u1) * Math.Cos(sigma) * Math.Cos(A12) - Math.Sin(u1) * Math.Sin(sigma);
double tanA2 = sinA2 / cosA2; double A2 = Math.Abs(Math.Atan(sinA2 / cosA2));
double sinA1 = Math.Sin(A12);
if (sinA1 < 0 && tanA2 > 0)
{
A2 = A2;
}
if (sinA1 < 0 && tanA2 < 0)
{
A2 = Math.PI - A2;
}
if (sinA1 > 0 && tanA2 > 0)
{
A2 = Math.PI + A2;
}
if (sinA1 > 0 && tanA2 < 0)
{
A2 = 2 * Math.PI - A2;
}
double sinU2 = Math.Sin(u1) * Math.Cos(sigma) + Math.Cos(u1) * Math.Cos(A12) * Math.Sin(sigma);
double B2 = Math.Atan(sinU2 / Math.Sqrt(1 - e2) / Math.Sqrt(1 - sinU2 * sinU2));
double sinl = Math.Sin(A12) * Math.Sin(sigma);
double cosl = Math.Cos(u1) * Math.Cos(sigma) - Math.Sin(u1) * Math.Sin(sigma) * Math.Cos(A12);
double tanlambda = sinl / cosl; double lambda = Math.Abs(Math.Atan(sinl / cosl));
if (tanlambda > 0 && sinA1 > 0)
{
lambda = lambda;
}
if (tanlambda < 0 && sinA1 > 0)
{
lambda = Math.PI - lambda;
}
if (tanlambda < 0 && sinA1 < 0)
{
lambda = -lambda;
}
if (tanlambda > 0 && sinA1 < 0)
{
lambda = lambda - Math.PI;
}
double e4 = e2 * e2;
double e6 = e4 * e2;
xk2 = e2 * cosA0 * cosA0;
xk4 = xk2 * xk2;
xk6 = xk4 * xk2;
double alpha1 = (e2 / 2 + e4 / 8 + e6 / 16) - e2 * (1 + e2) * xk2 / 16 + 3 * xk4 * e2 / 128;
double beta1 = e2 * (1 + e2) * xk2 / 16 - e2 * xk4 / 32;
double gamma1 = e2 * xk4 / 256;
double l0 = alpha1 * sigma + beta1 * Math.Sin(sigma) * Math.Cos(2 * sigma1 + sigma);
l0 = l0 + gamma1 * Math.Sin(2 * sigma) * Math.Cos(4 * sigma1 + 2 * sigma);
double ll = lambda - sinA0 * l0;
double L2 = L1 + ll;
geodesic.P2 = new Pointinfo();
geodesic.P2.B = GeoPro.RAD2DMS(B2);
geodesic.P2.L = GeoPro.RAD2DMS(L2);
geodesic.A21 = GeoPro.RAD2DMS(A2);
}