/// <summary>
/// Returns the inverse of this projection.
/// </summary>
/// <returns>IMathTransform that is the reverse of the current projection.</returns>
public override IMathTransform Inverse()
{
if (_inverse == null)
{
_inverse = new KrovakProjection(_Parameters.ToProjectionParameter(), this);
}
return(_inverse);
}
/// <summary>
/// Creates an instance of an Albers projection object.
/// </summary>
/// <remarks>
/// <para>The parameters this projection expects are listed below.</para>
/// <list type="table">
/// <listheader><term>Parameter</term><description>Description</description></listheader>
/// <item><term>latitude_of_origin</term><description>The latitude of the point which is not the natural origin and at which grid coordinate values false easting and false northing are defined.</description></item>
/// <item><term>central_meridian</term><description>The longitude of the point which is not the natural origin and at which grid coordinate values false easting and false northing are defined.</description></item>
/// <item><term>standard_parallel_1</term><description>For a conic projection with two standard parallels, this is the latitude of intersection of the cone with the ellipsoid that is nearest the pole. Scale is true along this parallel.</description></item>
/// <item><term>standard_parallel_2</term><description>For a conic projection with two standard parallels, this is the latitude of intersection of the cone with the ellipsoid that is furthest from the pole. Scale is true along this parallel.</description></item>
/// <item><term>false_easting</term><description>The easting value assigned to the false origin.</description></item>
/// <item><term>false_northing</term><description>The northing value assigned to the false origin.</description></item>
/// </list>
/// </remarks>
/// <param name="parameters">List of parameters to initialize the projection.</param>
/// <param name="inverse">Indicates whether the projection forward (meters to degrees or degrees to meters).</param>
protected KrovakProjection(IEnumerable <ProjectionParameter> parameters, KrovakProjection inverse)
: base(parameters, inverse)
{
Name = "Krovak";
Authority = "EPSG";
AuthorityCode = 9819;
//PROJCS["S-JTSK (Ferro) / Krovak",
//GEOGCS["S-JTSK (Ferro)",
// DATUM["D_S_JTSK_Ferro",
// SPHEROID["Bessel 1841",6377397.155,299.1528128]],
// PRIMEM["Ferro",-17.66666666666667],
// UNIT["degree",0.0174532925199433]],
//PROJECTION["Krovak"],
//PARAMETER["latitude_of_center",49.5],
//PARAMETER["longitude_of_center",42.5],
//PARAMETER["azimuth",30.28813972222222],
//PARAMETER["pseudo_standard_parallel_1",78.5],
//PARAMETER["scale_factor",0.9999],
//PARAMETER["false_easting",0],
//PARAMETER["false_northing",0],
//UNIT["metre",1]]
//Check for missing parameters
_azimuth = Degrees2Radians(_Parameters.GetParameterValue("azimuth"));
_pseudoStandardParallel = Degrees2Radians(_Parameters.GetParameterValue("pseudo_standard_parallel_1"));
// Calculates useful constants.
_sinAzim = Math.Sin(_azimuth);
_cosAzim = Math.Cos(_azimuth);
_n = Math.Sin(_pseudoStandardParallel);
_tanS2 = Math.Tan(_pseudoStandardParallel / 2 + S45);
var sinLat = Math.Sin(lat_origin);
var cosLat = Math.Cos(lat_origin);
var cosL2 = cosLat * cosLat;
_alfa = Math.Sqrt(1 + ((_es * (cosL2 * cosL2)) / (1 - _es))); // parameter B
_hae = _alfa * _e / 2;
var u0 = Math.Asin(sinLat / _alfa);
var esl = _e * sinLat;
var g = Math.Pow((1 - esl) / (1 + esl), (_alfa * _e) / 2);
_k1 = Math.Pow(Math.Tan(lat_origin / 2 + S45), _alfa) * g / Math.Tan(u0 / 2 + S45);
_ka = Math.Pow(1 / _k1, -1 / _alfa);
double radius = Math.Sqrt(1 - _es) / (1 - (_es * (sinLat * sinLat)));
_ro0 = scale_factor * radius / Math.Tan(_pseudoStandardParallel);
_rop = _ro0 * Math.Pow(_tanS2, _n);
}
