/// <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 AlbersProjection(_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>Items</term><description>Descriptions</description></listheader>
/// <item><term>latitude_of_center</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>longitude_of_center</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 AlbersProjection(IEnumerable <ProjectionParameter> parameters, AlbersProjection inverse)
: base(parameters, inverse)
{
Name = "Albers_Conic_Equal_Area";
var lat0 = lat_origin;
var lat1 = Degrees2Radians(_Parameters.GetParameterValue("standard_parallel_1"));
var lat2 = Degrees2Radians(_Parameters.GetParameterValue("standard_parallel_2"));
if (Math.Abs(lat1 + lat2) < double.Epsilon)
{
throw new ArgumentException("Equal latitudes for standard parallels on opposite sides of Equator.");
}
var alpha1 = alpha(lat1);
var alpha2 = alpha(lat2);
var m1 = Math.Cos(lat1) / Math.Sqrt(1 - _es * Math.Pow(Math.Sin(lat1), 2));
var m2 = Math.Cos(lat2) / Math.Sqrt(1 - _es * Math.Pow(Math.Sin(lat2), 2));
_n = (Math.Pow(m1, 2) - Math.Pow(m2, 2)) / (alpha2 - alpha1);
_c = Math.Pow(m1, 2) + (_n * alpha1);
_ro0 = Ro(alpha(lat0));
/*
* double sin_p0 = Math.Sin(lat0);
* double cos_p0 = Math.Cos(lat0);
* double q0 = qsfnz(e, sin_p0, cos_p0);
*
* double sin_p1 = Math.Sin(lat1);
* double cos_p1 = Math.Cos(lat1);
* double m1 = msfnz(e,sin_p1,cos_p1);
* double q1 = qsfnz(e,sin_p1,cos_p1);
*
*
* double sin_p2 = Math.Sin(lat2);
* double cos_p2 = Math.Cos(lat2);
* double m2 = msfnz(e,sin_p2,cos_p2);
* double q2 = qsfnz(e,sin_p2,cos_p2);
*
* if (Math.Abs(lat1 - lat2) > EPSLN)
* ns0 = (m1 * m1 - m2 * m2)/ (q2 - q1);
* else
* ns0 = sin_p1;
* C = m1 * m1 + ns0 * q1;
* rh = this._semiMajor * Math.Sqrt(C - ns0 * q0)/ns0;
*/
}
