/// <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 t;
if (projInfo.StandardParallel1 != null)
{
t = projInfo.StandardParallel1.Value.FromDegreesToRadians();
}
else
{
t = projInfo.lat_ts.Value.FromDegreesToRadians();
}
if ((K0 = Math.Cos(t)) < 0)
{
throw new ProjectionException(-24);
}
if (!IsElliptical)
{
return;
}
t = Math.Sin(t);
K0 /= Math.Sqrt(1 - Es * t * t);
E = Math.Sqrt(Es);
_apa = Proj.Authset(Es);
_qp = Proj.Qsfn(1, E, OneEs);
}
/// <inheritdoc />
protected override void EllipticalForward(double[] lp, double[] xy, int startIndex, int numPoints)
{
for (int i = startIndex; i < startIndex + numPoints; i++)
{
int phi = i * 2 + PHI;
int lam = i * 2 + LAMBDA;
int x = i * 2 + X;
int y = i * 2 + Y;
xy[x] = K0 * lp[lam];
xy[y] = .5 * Proj.Qsfn(Math.Sin(lp[phi]), E, OneEs) / K0;
}
}
/// <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 t = Math.Abs(Phi0);
if (Math.Abs(t - HALF_PI) < EPS10)
{
_mode = Phi0 < 0 ? Modes.SouthPole : Modes.NorthPole;
}
else if (Math.Abs(t) < EPS10)
{
_mode = Modes.Equitorial;
}
else
{
_mode = Modes.Oblique;
}
if (Es == 0)
{
IsElliptical = false;
_mode = Modes.Oblique;
_sinb1 = Math.Sin(Phi0);
_cosb1 = Math.Cos(Phi0);
return;
}
IsElliptical = true;
_qp = Proj.Qsfn(1, Es, OneEs);
// _mmf = .5/(1 - Es);
_apa = Proj.Authset(Es);
switch (_mode)
{
case Modes.NorthPole:
case Modes.SouthPole:
_dd = 1;
break;
case Modes.Equitorial:
_dd = 1 / (_rq = Math.Sqrt(.5 * _qp));
_xmf = 1;
_ymf = .5 * _qp;
break;
case Modes.Oblique:
_rq = Math.Sqrt(.5 * _qp);
double sinphi = Math.Sin(Phi0);
_sinb1 = Proj.Qsfn(sinphi, E, OneEs);
_cosb1 = Math.Sqrt(1 - _sinb1 * _sinb1);
_dd = Math.Cos(Phi0) / (Math.Sqrt(1 - Es * sinphi * sinphi) * _rq * _cosb1);
_ymf = _xmf = _rq / _dd;
_xmf *= _dd;
break;
}
}
/// <summary>
/// Internal code handling the setup operations for the transform
/// </summary>
protected void Setup()
{
double sinphi;
if (Math.Abs(_phi1 + _phi2) < EPS10)
{
throw new ProjectionException(-21);
}
_n = sinphi = Math.Sin(_phi1);
double cosphi = Math.Cos(_phi1);
bool secant = Math.Abs(_phi1 - _phi2) >= EPS10;
if (IsElliptical)
{
double m1 = Proj.Msfn(sinphi, cosphi, Es);
double ml1 = Proj.Qsfn(sinphi, E, OneEs);
if (secant)
{ /* secant cone */
sinphi = Math.Sin(_phi2);
cosphi = Math.Cos(_phi2);
double m2 = Proj.Msfn(sinphi, cosphi, Es);
double ml2 = Proj.Qsfn(sinphi, E, OneEs);
_n = (m1 * m1 - m2 * m2) / (ml2 - ml1);
}
_ec = 1 - .5 * OneEs * Math.Log((1 - E) / (1 + E)) / E;
_c = m1 * m1 + _n * ml1;
_dd = 1 / _n;
_rho0 = _dd * Math.Sqrt(_c - _n * Proj.Qsfn(Math.Sin(Phi0), E, OneEs));
}
else
{
if (secant)
{
_n = .5 * (_n + Math.Sin(_phi2));
}
_n2 = _n + _n;
_c = cosphi * cosphi + _n2 * sinphi;
_dd = 1 / _n;
_rho0 = _dd * Math.Sqrt(_c - _n2 * Math.Sin(Phi0));
}
}
/// <inheritdoc />
protected override void OnForward(double[] lp, double[] xy, int startIndex, int numPoints)
{
for (int i = startIndex; i < startIndex + numPoints; i++)
{
int phi = i * 2 + PHI;
int lam = i * 2 + LAMBDA;
int x = i * 2 + X;
int y = i * 2 + Y;
if ((_rho = _c - (IsElliptical
? _n * Proj.Qsfn(Math.Sin(lp[phi]),
E, OneEs)
: _n2 *Math.Sin(lp[phi]))) < 0)
{
xy[x] = double.NaN;
xy[y] = double.NaN;
continue;
//throw new ProjectionException(20);
}
_rho = _dd * Math.Sqrt(_rho);
xy[x] = _rho * Math.Sin(lp[lam] *= _n);
xy[y] = _rho0 - _rho * Math.Cos(lp[lam]);
}
}
/// <inheritdoc />
protected override void EllipticalForward(double[] lp, double[] xy, int startIndex, int numPoints)
{
for (int i = startIndex; i < startIndex + numPoints; i++)
{
int phi = i * 2 + PHI;
int lam = i * 2 + LAMBDA;
int x = i * 2 + X;
int y = i * 2 + Y;
double sinb = 0, cosb = 0, b = 0;
double coslam = Math.Cos(lp[lam]);
double sinlam = Math.Sin(lp[lam]);
double sinphi = Math.Sin(lp[phi]);
double q = Proj.Qsfn(sinphi, E, OneEs);
if (_mode == Modes.Oblique || _mode == Modes.Equitorial)
{
sinb = q / _qp;
cosb = Math.Sqrt(1 - sinb * sinb);
}
switch (_mode)
{
case Modes.Oblique:
b = 1 + _sinb1 * sinb + _cosb1 * cosb * coslam;
break;
case Modes.Equitorial:
b = 1 + cosb * coslam;
break;
case Modes.NorthPole:
b = HALF_PI + lp[phi];
q = _qp - q;
break;
case Modes.SouthPole:
b = lp[phi] - HALF_PI;
q = _qp + q;
break;
}
if (Math.Abs(b) < EPS10)
{
xy[x] = double.NaN;
xy[y] = double.NaN;
continue;
//throw new ProjectionException(20);
}
switch (_mode)
{
case Modes.Oblique:
xy[y] = _ymf * (b = Math.Sqrt(2 / b)) * (_cosb1 * sinb - _sinb1 * cosb * coslam);
xy[x] = _xmf * b * cosb * sinlam;
break;
case Modes.Equitorial:
xy[y] = (b = Math.Sqrt(2 / (1 + cosb * coslam))) * sinb * _ymf;
xy[x] = _xmf * b * cosb * sinlam;
break;
case Modes.NorthPole:
case Modes.SouthPole:
if (q >= 0)
{
xy[x] = (b = Math.Sqrt(q)) * sinlam;
xy[y] = coslam * (_mode == Modes.SouthPole ? b : -b);
}
else
{
xy[x] = xy[y] = 0;
}
break;
}
}
}
