/// <summary>
/// Initializes the transform using the parameters from the specified coordinate system information
/// </summary>
/// <param name="projInfo">A ProjectionInfo class contains all the standard and custom parameters needed to initialize this transform</param>
protected override void OnInit(ProjectionInfo projInfo)
{
const double phi_0 = 0.0;
_rok = A/K0;
_rtk = A*K0;
if (projInfo.Parameters.ContainsKey("alpha"))
{
double alpha = projInfo.ParamR("alpha");
double lonz = projInfo.ParamR("lonc");
_singam = Math.Atan(-Math.Cos(alpha)/(-Math.Sin(phi_0)*Math.Sin(alpha))) + lonz;
_sinphi = Math.Asin(Math.Cos(phi_0)*Math.Sin(alpha));
}
else
{
double phi_1 = projInfo.GetPhi1();
double phi_2 = projInfo.GetPhi2();
double lam_1 = projInfo.ParamR("lon_1");
double lam_2 = projInfo.ParamR("lon_2");
_singam = Math.Atan2(Math.Cos(phi_1)*Math.Sin(phi_2)*Math.Cos(lam_1) -
Math.Sin(phi_1)*Math.Cos(phi_2)*Math.Cos(lam_2),
Math.Sin(phi_1)*Math.Cos(phi_2)*Math.Sin(lam_2) -
Math.Cos(phi_1)*Math.Sin(phi_2)*Math.Sin(lam_1));
_sinphi = Math.Atan(-Math.Cos(_singam - lam_1)/Math.Tan(phi_1));
}
Lam0 = _singam + HalfPi;
_cosphi = Math.Cos(_sinphi);
_sinphi = Math.Sin(_sinphi);
_singam = Math.Sin(_singam);
}