public override Coordinate ProjectInverse(double x, double y, Coordinate lp)
{
if (Spherical)
{
double t;
if ((t = Math.Abs(y *= ScaleFactor)) - EPS10 <= 1.0)
{
if (t >= 1.0)
{
lp.Y = y < 0.0 ? -ProjectionMath.PiHalf : ProjectionMath.PiHalf;
}
else
{
lp.Y = Math.Asin(y);
}
lp.X = x / ScaleFactor;
}
else
{
throw new ProjectionException();
}
}
else
{
lp.Y = ProjectionMath.AuthLat(Math.Asin(2.0 * y * ScaleFactor / _qp), _apa);
lp.X = x / ScaleFactor;
}
return(lp);
}
protected void ProjectInverseNonSpherical(double xyx, double xyy, Coordinate dst)
{
double lpphi, lplam;
double cCe, sCe, q, rho, ab = 0.0;
switch (mode)
{
case AzimuthalMode.Equator:
case AzimuthalMode.Oblique:
if ((rho = ProjectionMath.Hypot(xyx /= dd, xyy *= dd)) < EPS10)
{
lplam = 0.0;
lpphi = phi0;
dst.X = lplam;
dst.Y = lpphi;
return;
}
cCe = Math.Cos(sCe = 2.0 * Math.Asin(.5 * rho / rq));
xyx *= (sCe = Math.Sin(sCe));
if (mode == AzimuthalMode.Oblique)
{
q = qp * (ab = cCe * sinb1 + xyy * sCe * cosb1 / rho);
xyy = rho * cosb1 * cCe - xyy * sinb1 * sCe;
}
else
{
q = qp * (ab = xyy * sCe / rho);
xyy = rho * cCe;
}
break;
case AzimuthalMode.NorthPole:
case AzimuthalMode.SouthPole:
if (mode == AzimuthalMode.NorthPole)
{
xyy = -xyy;
}
if (0 == (q = (xyx * xyx + xyy * xyy)))
{
lplam = 0.0;
lpphi = phi0;
dst.X = lplam;
dst.Y = lpphi;
return;
}
/*
* q = P->qp - q;
*/
ab = 1.0 - q / qp;
if (mode == AzimuthalMode.SouthPole)
{
ab = -ab;
}
break;
}
lplam = Math.Atan2(xyx, xyy);
lpphi = ProjectionMath.AuthLat(Math.Asin(ab), apa);
dst.X = lplam;
dst.Y = lpphi;
}
public ProjCoordinate projectInverse(double x, double y, ProjCoordinate lp)
{
if (Spherical)
{
double cosz = 0, rh, sinz = 0;
rh = ProjectionMath.Distance(x, y);
if ((lp.Y = rh * .5) > 1.0)
{
throw new ProjectionException();
}
lp.Y = 2.0 * Math.Asin(lp.Y);
if (Mode == AzimuthalMode.Oblique || Mode == AzimuthalMode.Equator)
{
sinz = Math.Sin(lp.Y);
cosz = Math.Cos(lp.Y);
}
switch (Mode)
{
case AzimuthalMode.Equator:
lp.Y = Math.Abs(rh) <= EPS10 ? 0.0 : Math.Asin(y * sinz / rh);
x *= sinz;
y = cosz * rh;
break;
case AzimuthalMode.Oblique:
lp.Y = Math.Abs(rh) <= EPS10 ? ProjectionLatitude :
Math.Asin(cosz * _sinphi0 + y * sinz * _cosphi0 / rh);
x *= sinz * _cosphi0;
y = (cosz - Math.Sin(lp.Y) * _sinphi0) * rh;
break;
case AzimuthalMode.NorthPole:
y = -y;
lp.Y = ProjectionMath.PiHalf - lp.Y;
break;
case AzimuthalMode.SouthPole:
lp.Y -= ProjectionMath.PiHalf;
break;
}
lp.X = (y == 0.0 && (Mode == AzimuthalMode.Equator || Mode == AzimuthalMode.Oblique)) ?
0.0 : Math.Atan2(x, y);
}
else
{
double cCe, sCe, q, rho, ab = 0;
switch (Mode)
{
case AzimuthalMode.Equator:
case AzimuthalMode.Oblique:
if ((rho = ProjectionMath.Distance(x /= _dd, y *= _dd)) < EPS10)
{
lp.X = 0.0;
lp.Y = ProjectionLatitude;
return(lp);
}
cCe = Math.Cos(sCe = 2.0 * Math.Asin(.5 * rho / _rq));
x *= (sCe = Math.Sin(sCe));
if (Mode == AzimuthalMode.Oblique)
{
q = _qp * (ab = cCe * _sinb1 + y * sCe * _cosb1 / rho);
y = rho * _cosb1 * cCe - y * _sinb1 * sCe;
}
else
{
q = _qp * (ab = y * sCe / rho);
y = rho * cCe;
}
break;
case AzimuthalMode.NorthPole:
case AzimuthalMode.SouthPole:
if (Mode == AzimuthalMode.NorthPole)
{
y = -y;
}
if ((q = (x * x + y * y)) == 0)
{
lp.X = 0.0;
lp.Y = ProjectionLatitude;
return(lp);
}
ab = 1.0 - q / _qp;
if (Mode == AzimuthalMode.SouthPole)
{
ab = -ab;
}
break;
}
lp.X = Math.Atan2(x, y);
lp.Y = ProjectionMath.AuthLat(Math.Asin(ab), _apa);
}
return(lp);
}
