/// <summary>
/// The forward transform from geodetic units to linear units
/// </summary>
/// <param name="lp">The array of lambda, phi coordinates</param>
/// <param name="xy">The array of x, y coordinates</param>
protected override void OnForward(double[] lp, double[] xy)
{
double t, dl1, dl2;
double sp = Math.Sin(lp[Phi]);
double cp = Math.Cos(lp[Phi]);
double z1 = Proj.Aacos(_sp1 * sp + _cp1 * cp * Math.Cos(dl1 = lp[Lambda] + _dlam2));
double z2 = Proj.Aacos(_sp2 * sp + _cp2 * cp * Math.Cos(dl2 = lp[Lambda] - _dlam2));
z1 *= z1;
z2 *= z2;
xy[X] = _r2z0 * (t = z1 - z2);
t = _z02 - t;
xy[Y] = _r2z0 * Proj.Asqrt(4 * _z02 * z2 - t * t);
if ((_ccs * sp - cp * (_cs * Math.Sin(dl1) - _sc * Math.Sin(dl2))) < 0)
{
xy[Y] = -xy[Y];
}
}
/// <summary>
/// The inverse transform from linear units to geodetic units
/// </summary>
/// <param name="xy">The double values for the input x and y values stored in an array</param>
/// <param name="lp">The double values for the output lambda and phi values stored in an array</param>
protected override void OnInverse(double[] xy, double[] lp)
{
lp[Phi] = xy[Y] / Cy;
lp[Lambda] = xy[X] / (Cx * (Ca + Proj.Asqrt(1 - Cb * lp[Phi] * lp[Phi])));
}
/// <summary>
/// The forward transform from geodetic units to linear units
/// </summary>
/// <param name="lp">The array of lambda, phi coordinates</param>
/// <param name="xy">The array of x, y coordinates</param>
protected override void OnForward(double[] lp, double[] xy)
{
xy[Y] = Cy * lp[Phi];
xy[X] = Cx * lp[Lambda] * (Ca + Proj.Asqrt(1 - Cb * lp[Phi] * lp[Phi]));
}
