public override IMathTransform Inverse()
{
if (_inverse == null)
{
_inverse = new HotineObliqueMercatorProjection(_Parameters.ToProjectionParameter(), this);
}
return(_inverse);
}
public HotineObliqueMercatorProjection(IEnumerable <ProjectionParameter> parameters, HotineObliqueMercatorProjection inverse)
: base(parameters, inverse)
{
Authority = "EPSG";
AuthorityCode = 9812;
Name = "Hotine_Oblique_Mercator";
_azimuth = Degrees2Radians(_Parameters.GetParameterValue("azimuth"));
var rectifiedGridAngle = Degrees2Radians(_Parameters.GetParameterValue("rectified_grid_angle"));
sincos(lat_origin, out _sinP20, out _cosP20);
var con = 1.0 - _es * Math.Pow(_sinP20, 2);
var com = Math.Sqrt(1.0 - _es);
_bl = Math.Sqrt(1.0 + _es * Math.Pow(_cosP20, 4.0) / (1.0 - _es));
_al = _semiMajor * _bl * scale_factor * com / con;
double f;
if (Math.Abs(lat_origin) < EPSLN)
{
//ts = 1.0;
_d = 1.0;
_el = 1.0;
f = 1.0;
}
else
{
var ts = tsfnz(_e, lat_origin, _sinP20);
con = Math.Sqrt(con);
_d = _bl * com / (_cosP20 * con);
if ((_d * _d - 1.0) > 0.0)
{
if (lat_origin >= 0.0)
{
f = _d + Math.Sqrt(_d * _d - 1.0);
}
else
{
f = _d - Math.Sqrt(_d * _d - 1.0);
}
}
else
{
f = _d;
}
_el = f * Math.Pow(ts, _bl);
}
var g = .5 * (f - 1.0 / f);
var gama = asinz(Math.Sin(_azimuth) / _d);
lon_origin = lon_origin - asinz(g * Math.Tan(gama)) / _bl;
con = Math.Abs(lat_origin);
if ((con > EPSLN) && (Math.Abs(con - HALF_PI) > EPSLN))
{
sincos(gama, out _singam, out _cosgam);
sincos(_azimuth, out _sinaz, out _cosaz);
if (lat_origin >= 0)
{
_u = (_al / _bl) * Math.Atan(Math.Sqrt(_d * _d - 1.0) / _cosaz);
}
else
{
_u = -(_al / _bl) * Math.Atan(Math.Sqrt(_d * _d - 1.0) / _cosaz);
}
}
else
{
throw new ArgumentException("Input data error");
}
sincos(rectifiedGridAngle, out _singrid, out _cosgrid);
}
