protected void ProjectInverseSpherical(double xyx, double xyy, Coordinate dst)
{
double cosz = 0.0, rh, sinz = 0.0;
double lpphi, lplam;
rh = ProjectionMath.Hypot(xyx, xyy);
if ((lpphi = rh * .5) > 1.0)
{
throw new ProjectionException("I_ERROR");
}
lpphi = 2.0 * Math.Asin(lpphi);
if (mode == AzimuthalMode.Oblique || mode == AzimuthalMode.Equator)
{
sinz = Math.Sin(lpphi);
cosz = Math.Cos(lpphi);
}
switch (mode)
{
case AzimuthalMode.Equator:
lpphi = Math.Abs(rh) <= EPS10 ? 0.0 : Math.Asin(xyy * sinz / rh);
xyx *= sinz;
xyy = cosz * rh;
break;
case AzimuthalMode.Oblique:
lpphi = Math.Abs(rh) <= EPS10
? phi0
: Math.Asin(cosz * sinph0 + xyy * sinz * cosph0 / rh);
xyx *= sinz * cosph0;
xyy = (cosz - Math.Sin(lpphi) * sinph0) * rh;
break;
case AzimuthalMode.NorthPole:
xyy = -xyy;
lpphi = ProjectionMath.PiHalf - lpphi;
break;
case AzimuthalMode.SouthPole:
lpphi -= ProjectionMath.PiHalf;
break;
}
lplam = (xyy == 0.0 && (mode == AzimuthalMode.Equator || mode == AzimuthalMode.Oblique))
? 0.0
: Math.Atan2(xyx, xyy);
dst.X = lplam;
dst.Y = lpphi;
}
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;
}
