//反算
public override void GetBLFromXY(decimal x, decimal y, ref decimal B, ref decimal L)
{
//this.GetBLFromXY(x, y, ref B, ref L, 0, EnumProjectionDatum.Xian80, this.Strip, this.L0, this.IsBigNumber);
//去掉大数和东移500公里
decimal y1 = y - 500000.0M;
if (this.IsBigNumber == true)
{
y1 = y1 - (this.L0 / (int)this.Strip) * 1000000M;
}
//计算临时参数
decimal E = K0 * x;
decimal CosE = Maths.Cos(E);
decimal SinE = Maths.Sin(E);
decimal SinE3 = SinE * SinE * SinE;
decimal SinE5 = SinE3 * SinE * SinE;
decimal SinE7 = SinE5 * SinE * SinE;
//求底点纬度
decimal Bf = E + CosE * (K1 * SinE - K2 * SinE3 + K3 * SinE5 - K4 * SinE7);
//计算临时参数
decimal CosBf = Maths.Cos(Bf);
decimal CosBf2 = CosBf * CosBf;
decimal t = Maths.Tan(Bf);
decimal η2 = e12 * CosBf2;
decimal C = a * a / b;
decimal V = Maths.Sqrt(1 + η2);
decimal N = C / V;
decimal V2 = V * V;
decimal t2 = t * t;
decimal t4 = t2 * t2;
decimal y1_N = y1 / N;
decimal y1_N2 = y1_N * y1_N;
decimal y1_N3 = y1_N2 * y1_N;
decimal y1_N4 = y1_N3 * y1_N;
decimal y1_N5 = y1_N4 * y1_N;
decimal y1_N6 = y1_N5 * y1_N;
decimal V2t = V * V * t;
//计算经纬度值B,L
B = Bf - (V2t * y1_N2) / 2 + ((5 + 3 * t2 + η2 - 9 * η2 * t2) * V2t * y1_N4 * 1.0M) / 24 - ((61 + 90 * t2 + 45 * t4) * V2t * y1_N6 * 1.0M) / 720;
L = y1_N * 1.0M / CosBf - (1 + 2 * t2 + η2) * (1.0M / CosBf) * y1_N3 / 6 + (5 + 28 * t2 + 24 * t2 + 6 * η2 + 8 * η2 * t2) * (1.0M / CosBf) * y1_N5 * 1.0M / 120;
AngleUnit_D dUnit = new AngleUnit_D(this.L0);
L = L + dUnit.getArcDValue(); //弧度
//弧度->度
AngleUnit_ArcD acUnit = new AngleUnit_ArcD(B);
dUnit = new AngleUnit_D(acUnit);
B = (decimal)dUnit.getAngle();
acUnit = new AngleUnit_ArcD(L);
dUnit = new AngleUnit_D(acUnit);
L = (decimal)dUnit.getAngle();
}
/// <summary>
/// 大地坐标转换为高斯投影坐标 正解公式
/// WGC84->高斯投影
/// Description:
///' 大地坐标转换为高斯投影坐标
///' Parameters:
///' LX,BX - 输入，经纬度坐标
///' x,y - 输出，高斯投影坐标(大数)
///' nearright - 输入，L是相邻两带的分界线时的取法，0 - 左带（小），1 - 右带（大）
///' ProjectionType - 输入，1 - 80坐标系，0 - 54坐标系
///' StripType - 输入，1 - 6度分带，0 - 3度分带
/// 当只有一个已知控制点时，根据平移参数调整东伪偏移、北纬偏移值实现WGS84到北京54的转换
/// 东伪偏移=东伪偏移值=tpMainStrip * 1000000+500000.0
/// 北纬偏移值=0;
/// </summary>
/// <param name="BX">大地纬度B</param>
/// <param name="LX">大地经度L</param>
/// <param name="x">高斯投影X</param>
/// <param name="y">高斯投影Y</param>
/// <param name="nearright">输入，L是相邻两带的分界线时的取法，0 - 左带（小），1 - 右带（大）</param>
/// <param name="ProjectionType"> 输入，1 - 80坐标系，0 - 54坐标系</param>
/// <param name="StripType"> 输入，1 - 6度分带，0 - 3度分带</param>
/// <param name="IsBigNumber">输入, 是大数坐标吗？</param>
public void GetXYFromBL(decimal BX, decimal LX, ref decimal x, ref decimal y, long nearright, EnumProjectionDatum ProjectionType, EnumStrip StripType, bool IsBigNumber)
{
decimal t = 0;
decimal B = 0;
decimal L = 0;
decimal x0 = 0;
decimal y2 = 0;
decimal E12 = 0;
decimal c0 = 0;
decimal n1 = 0;
decimal m = 0;
decimal temp1 = 0, temp2 = 0;
decimal LX1 = 0;
decimal fc_pi = 3.14159265358979M; //PI值
B = (BX / 180) * fc_pi; //转为弧度值bx*(PI/180)
L = (LX / 180) * fc_pi; //转为弧度值lx*(PI/180)
//求带内中央子午线经度
LX1 = GetLocalLongitude(LX, nearright, StripType);
m = Maths.Cos(B) * fc_pi * LX1 / 180.0M;
t = Maths.Tan(B);
switch (ProjectionType)
{
case EnumProjectionDatum.Xian80: //80坐标
c0 = 6399596.65198801M;
E12 = 0.0067395018195M;
x0 = 111133.0047M * BX - (32009.8575M * Maths.Sin(B) + 133.9978M * (Maths.Pow(Maths.Sin(B), 3)) + 0.6975M * (Maths.Pow(Maths.Sin(B), 5)) + 0.0039M * (Maths.Pow(Maths.Sin(B), 7))) * Maths.Cos(B);
break;
case EnumProjectionDatum.Bejing54: //54坐标
c0 = 6399698.90178271M;
E12 = 0.00673852541468M;
x0 = 111134.8611M * BX - (32005.7798M * Maths.Sin(B) + 133.9614M * (Maths.Pow(Maths.Sin(B), 3)) + 0.6972M * (Maths.Pow(Maths.Sin(B), 5)) + 0.0039M * (Maths.Pow(Maths.Sin(B), 7))) * Maths.Cos(B);
break;
default: //其它暂为空
break;
}
y2 = E12 * (Maths.Pow(Maths.Cos(B), 2));
n1 = c0 / Maths.Sqrt(1.0M + y2);
temp1 = (Maths.Pow(m, 2)) / 2.0M + (5.0M - (Maths.Pow(t, 2)) + 9.0M * y2 + 4 * (Maths.Pow(y2, 2))) * (Maths.Pow(m, 4)) / 24.0M + (61.0M - 58.0M * (Maths.Pow(t, 2)) + (Maths.Pow(t, 4))) * (Maths.Pow(m, 6)) / 720.0M;
temp2 = m + (1.0M - (Maths.Pow(t, 2)) + y2) * (Maths.Pow(m, 3)) / 6.0M + (5.0M - 18.0M * (Maths.Pow(t, 2)) + (Maths.Pow(t, 4)) + 14.0M * y2 - 58.0M * y2 * (Maths.Pow(t, 2))) * (Maths.Pow(m, 5)) / 120.0M;
x = x0 + n1 * t * temp1;
y = n1 * temp2 + 500000.0M; //与中央经线的距离m //500000.0表示平移了500公里距离 目的是把负数坐标转为正数好处理
//主带数值（整数）
decimal tpMainStrip = 0; //主带数值
switch (StripType)
{
case EnumStrip.Strip3:
tpMainStrip = (int)Math.Truncate(LX / 3) + 1;
break;
case EnumStrip.Strip6:
tpMainStrip = (int)Math.Truncate(LX / 6) + 1;
break;
default: //则自动计算 ,默认为3度带
tpMainStrip = (int)Math.Truncate(LX / 3) + 1;
break;
}
//转为大数坐标y=带数*1000000+与中央经线的距离m
//东伪偏移值=tpMainStrip * 1000000+500000.0
if (IsBigNumber == true) //转为高斯投影是大数投影吗？即Zone 35带数 （小数投影为CM_105E)
{
y = y + tpMainStrip * 1000000;
}
}
/// <summary>
/// 高斯投影坐标转换为大地坐标 反解公式
/// Parameters:
/// x,y - 输入，高斯投影坐标(大数)
/// LX,BX - 输出，经纬度坐标
/// nearright - 输入，L是相邻两带的分界线时的取法，0 - 左带（小），1 - 右带（大）
/// ProjectionType - 输入，1 - 80坐标系，0 - 54坐标系
/// StripType - 输入，1 - 6度分带，0 - 3度分带
/// L0 - 输入, 3度或6度分带的中央子午线 单位为度
/// </summary>
/// <param name="x"> 输入，高斯投影X坐标</param>
/// <param name="y"> 输入，高斯投影Y坐标(大数)</param>
/// <param name="BX">输入，纬度坐标</param>
/// <param name="LX">输入，经度坐标</param>
/// <param name="nearright">输入，L是相邻两带的分界线时的取法，0 - 左带（小），1 - 右带（大）</param>
/// <param name="ProjectionType">输入，1 - 80坐标系，0 - 54坐标系</param>
/// <param name="StripType">输入，1 - 6度分带，0 - 3度分带</param>
/// <param name="L0">输入, 3度或6度分带的中央子午线 单位为度</param>
/// <param name="IsBigNumber">输入, 是大数坐标吗？</param>
/// <returns></returns>
public bool GetBLFromXY(decimal x, decimal y, ref decimal BX, ref decimal LX, int nearright, EnumProjectionDatum ProjectionType, EnumStrip StripType, decimal L0, bool IsBigNumber)
{
decimal a0 = 0;
decimal b0 = 0;
decimal c0 = 0;
decimal E12 = 0;
decimal bf0 = 0;
decimal bf = 0;
decimal tf = 0;
decimal yf2 = 0;
decimal n = 0;
decimal b1 = 0;
decimal l1 = 0;
decimal temp1 = 0;
long iStripNum = 0;
decimal fc_pi = 3.14159265358979M;
//要素的Y坐标中是否含有大地坐标的大数？
switch (StripType)
{
case EnumStrip.Strip6:
iStripNum = (long)Math.Round(L0 / 6);
break;
case EnumStrip.Strip3:
iStripNum = (long)Math.Round(L0 / 3);
break;
}
//认为高斯投影Y坐标为大数(y=带数*1000000 + 与中央经线的距离m
//要素的Y坐标包含有大地坐标吗？y=y+带数*1000000 + 与中央经线的距离m(500公里)
if (IsBigNumber == true)
{
y = y - iStripNum * 1000000;
}
x = x / 1000000;
y = y - 500000;
switch (ProjectionType)
{
case EnumProjectionDatum.Bejing54: //北京54
a0 = 6378245M; //长半轴 a（米）
b0 = 6356863.01877305M; //短半轴b（米）
c0 = 6399698.90178271M;
E12 = 0.0067385254147M;
bf0 = 27.11115372595M + 9.02468257083M * (x - 3) - 0.00579740442M * (Maths.Pow((x - 3), 2)) - 0.00043532572M * (Maths.Pow((x - 3), 3)) + 0.00004857285M * (Maths.Pow((x - 3), 4)) + 0.00000215727M * (Maths.Pow((x - 3), 5)) - 0.00000019399M * (Maths.Pow((x - 3), 6));
break;
case EnumProjectionDatum.Xian80: //西安80
a0 = 6378140M; //长半轴 a（米）
b0 = 6356755.28815753M; //短半轴b（米）
c0 = 6399596.65198801M;
E12 = 0.0067395018195M;
bf0 = 27.11162289465M + 9.02483657729M * (x - 3) - 0.00579850656M * (Maths.Pow((x - 3), 2)) - 0.00043540029M * (Maths.Pow((x - 3), 3)) + 0.00004858357M * (Maths.Pow((x - 3), 4)) + 0.00000215769M * (Maths.Pow((x - 3), 5)) - 0.00000019404M * (Maths.Pow((x - 3), 6));
break;
default: //暂为空
break;
}
bf = bf0 * fc_pi / 180;
tf = Maths.Tan(bf);
yf2 = E12 * (Maths.Pow(Maths.Cos(bf), 2));
n = y * Maths.Sqrt(1 + yf2) / c0;
temp1 = 90.0M * (Maths.Pow(n, 2)) - 7.5M * (5.0M + 3.0M * (Maths.Pow(tf, 2)) + yf2 - 9.0M * yf2 * (Maths.Pow(tf, 2))) * (Maths.Pow(n, 4)) + 0.25M * (61.0M + 90.0M * (Maths.Pow(tf, 2)) + 45.0M * (Maths.Pow(tf, 4))) * (Maths.Pow(n, 6));
b1 = bf0 - (1.0M + yf2) * tf * temp1 / fc_pi;
l1 = (180.0M * n - 30.0M * (1.0M + 2.0M * (Maths.Pow(tf, 2)) + yf2) * (Maths.Pow(n, 3)) + 1.5M * (5.0M + 28.0M * (Maths.Pow(tf, 2)) + 24.0M * (Maths.Pow(tf, 4))) * (Maths.Pow(n, 5))) / fc_pi / Maths.Cos(bf);
l1 = l1 + L0;
if (l1 < 0.0M)
{
l1 = l1 + 360.0M;
}
if (l1 >= 360.0M)
{
l1 = l1 - 360.0M;
}
BX = b1;
LX = l1;
return(true);
}