protected internal override void Unproject(double x, double y, out double latitude, out double longitude)
{
var ros = x * x + (_ro0 - y) * (_ro0 - y);
var a = _cOverN2 - ros * _nHalf;
if (double.IsNaN(a) || Math.Abs(a) > 1 + MathX.Tolerance)
{
throw new ArgumentOutOfRangeException(paramName: string.Join(",", new [] { nameof(x), nameof(y) }));
}
latitude = Math.Asin(MathX.Clamp(1, a));
longitude = MathX.Clamp(Math.PI, MathX.Atan2(x, _ro0 - y, "x, y") * _invN);
}
protected internal override void Project(double latitude, double longitude, out double x, out double y)
{
var sinLatitude = Math.Sin(latitude);
var cosLatitude = Math.Cos(latitude);
var sinLongitude = Math.Sin(longitude);
var cosLongitude = Math.Cos(longitude);
var a = _sinFiP * sinLatitude - _cosFiP * cosLatitude * sinLongitude; // sin_fi_p
if (double.IsNaN(a) || Math.Abs(a) > 1)
{
throw new ArgumentOutOfRangeException(string.Join(",", new[] { nameof(latitude), nameof(longitude) }));
}
x = MathX.Atan2(sinLatitude / cosLatitude * _cosFiP + sinLongitude * _sinFiP, cosLongitude, "latitude, longitude");
y = MathX.Clamp(MaxY, Math.Log((1 + a) / (1 - a)) / 2); // protect against +-Infinity
}
protected internal override void Unproject(double x, double y, out double latitude, out double longitude)
{
var sinX = Math.Sin(x);
var cosX = Math.Cos(x);
var sinhY = Math.Sinh(y);
var coshY = Math.Cosh(y);
// cosh_y >= 1 by definition
var a = (_sinFiP * sinhY + _cosFiP * sinX) / coshY;
if (Math.Abs(a) > 1)
{
throw new ArgumentOutOfRangeException(string.Join(",", new [] { nameof(x), nameof(y) }));
}
latitude = Math.Asin(a);
longitude = MathX.Atan2(_sinFiP * sinX - _cosFiP * sinhY, cosX, "x, y");
}
protected internal override void Unproject(double x, double y, out double latitude, out double longitude)
{
if (x >= MaxX)
{
latitude = 0;
longitude = Math.PI / 2;
}
else if (x <= -MaxX)
{
latitude = 0;
longitude = -Math.PI / 2;
}
else
{
// 1 <= cosh(x) <= cosh(MaxX)
latitude = Math.Asin(Math.Sin(y) / Math.Cosh(x));
// In case of x=0 and y=+-Pi/2: latitude will be +-90 and longitude will be 0
longitude = MathX.Atan2(Math.Sinh(x), Math.Cos(y));
}
}
