/// <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) { double pp; /* get control point locations */ double phi1 = projInfo.GetPhi1(); double lam1 = projInfo.GetLam1(); double phi2 = projInfo.GetPhi2(); double lam2 = projInfo.GetLam2(); if (phi1 == phi2 && lam1 == lam2) { throw new ProjectionException(-25); } Lam0 = Proj.Adjlon(0.5 * (lam1 + lam2)); _dlam2 = Proj.Adjlon(lam2 - lam1); _cp1 = Math.Cos(phi1); _cp2 = Math.Cos(phi2); _sp1 = Math.Sin(phi1); _sp2 = Math.Sin(phi2); _cs = _cp1 * _sp2; _sc = _sp1 * _cp2; _ccs = _cp1 * _cp2 * Math.Sin(_dlam2); _z02 = Proj.Aacos(_sp1 * _sp2 + _cp1 * _cp2 * Math.Cos(_dlam2)); _hz0 = .5 * _z02; double A12 = Math.Atan2(_cp2 * Math.Sin(_dlam2), _cp1 * _sp2 - _sp1 * _cp2 * Math.Cos(_dlam2)); _ca = Math.Cos(pp = Proj.Aasin(_cp1 * Math.Sin(A12))); _sa = Math.Sin(pp); _lp = Proj.Adjlon(Math.Atan2(_cp1 * Math.Cos(A12), _sp1) - _hz0); _dlam2 *= .5; _lamc = HalfPi - Math.Atan2(Math.Sin(A12) * _sp1, Math.Cos(A12)) - _dlam2; _thz0 = Math.Tan(_hz0); _rhshz0 = .5 / Math.Sin(_hz0); _r2z0 = 0.5 / _z02; _z02 *= _z02; }
/// <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) { double con; double f; double d; double toRadians = projInfo.GeographicInfo.Unit.Radians; _rot = projInfo.ParamI("no_rot") == 0; bool azi = projInfo.ParamD("alpha") != 0.0; if (azi) { _lamc = projInfo.ParamD("lonc") * toRadians; _alpha = projInfo.ParamD("alpha") * toRadians; if (Math.Abs(_alpha) < Tol || Math.Abs(Math.Abs(Phi0) - HalfPi) <= Tol || Math.Abs(Math.Abs(_alpha) - HalfPi) <= Tol) { throw new ProjectionException(32); } } else { _lam1 = projInfo.GetLam1(); _phi1 = projInfo.GetPhi1(); _lam2 = projInfo.GetLam2(); _phi2 = projInfo.GetPhi2(); if (Math.Abs(_phi1 - _phi2) <= Tol || (con = Math.Abs(_phi1)) <= Tol || Math.Abs(con - HalfPi) <= Tol || Math.Abs(Math.Abs(Phi0) - HalfPi) <= Tol || Math.Abs(Math.Abs(_phi2) - HalfPi) <= Tol) { throw new ProjectionException(33); } } _ellips = Es > 0; double com = _ellips ? Math.Sqrt(OneEs) : 1; if (Math.Abs(Phi0) > EPS10) { double sinph0 = Math.Sin(Phi0); double cosph0 = Math.Cos(Phi0); if (_ellips) { con = 1 - Es * sinph0 * sinph0; _bl = cosph0 * cosph0; _bl = Math.Sqrt(1 + Es * _bl * _bl / OneEs); _al = _bl * K0 * com / con; d = _bl * com / (cosph0 * Math.Sqrt(con)); } else { _bl = 1; _al = K0; d = 1 / cosph0; } if ((f = d * d - 1) <= 0) { f = 0; } else { f = Math.Sqrt(f); if (Phi0 < 0) { f = -f; } } _el = f += d; if (_ellips) { _el *= Math.Pow(Proj.Tsfn(Phi0, sinph0, E), _bl); } else { _el *= TSFN0(Phi0); } } else { _bl = 1 / com; _al = K0; _el = d = f = 1; } if (azi) { _gamma = Math.Asin(Math.Sin(_alpha) / d); Lam0 = _lamc - Math.Asin((.5 * (f - 1 / f)) * Math.Tan(_gamma)) / _bl; } else { double h; double l; if (_ellips) { h = Math.Pow(Proj.Tsfn(_phi1, Math.Sin(_phi1), E), _bl); l = Math.Pow(Proj.Tsfn(_phi2, Math.Sin(_phi2), E), _bl); } else { h = TSFN0(_phi1); l = TSFN0(_phi2); } f = _el / h; double p = (l - h) / (l + h); double j = _el * _el; j = (j - l * h) / (j + l * h); if ((con = _lam1 - _lam2) < -Math.PI) { _lam2 -= Math.PI * 2; } else if (con > Math.PI) { _lam2 += Math.PI * 2; } Lam0 = Proj.Adjlon(.5 * (_lam1 + _lam2) - Math.Atan(j * Math.Tan(.5 * _bl * (_lam1 - _lam2)) / p) / _bl); _gamma = Math.Atan(2 * Math.Sin(_bl * Proj.Adjlon(_lam1 - Lam0)) / (f - 1 / f)); _alpha = Math.Asin(d * Math.Sin(_gamma)); } _singam = Math.Sin(_gamma); _cosgam = Math.Cos(_gamma); if (projInfo.ParamI("rot_conv") != 0) { f = _gamma; } else { f = _alpha; } _sinrot = Math.Sin(f); _cosrot = Math.Cos(f); if (projInfo.ParamI("no_uoff") != 0) { _u0 = 0; } else { _u0 = Math.Abs(_al * Math.Atan(Math.Sqrt(d * d - 1) / _cosrot) / _bl); } if (Phi0 < 0) { _u0 = -_u0; } }