/// <summary>
/// Creates a new lambert projection.
/// </summary>
/// <param name="name"></param>
/// <param name="ellipsoid"></param>
/// <param name="standard_parallel_1"></param>
/// <param name="standard_parallel_2"></param>
/// <param name="latitude_origin_1"></param>
/// <param name="longitude_origin_2"></param>
/// <param name="x_origin"></param>
/// <param name="y_origin"></param>
protected LambertProjectionBase(string name,
LambertEllipsoid ellipsoid,
double standard_parallel_1,
double standard_parallel_2,
double latitude_origin_1,
double longitude_origin_2,
double x_origin,
double y_origin)
{
_name = name;
_ellipsoid = ellipsoid;
_standard_parallel_1 = standard_parallel_1;
Radian temp = new Degree(_standard_parallel_1);
_standard_parallel_1_radians = temp.Value;
_standard_parallel_2 = standard_parallel_2;
temp = new Degree(_standard_parallel_2);
_standard_parallel_2_radians = temp.Value;
_latitude_origin = latitude_origin_1;
temp = new Degree(_latitude_origin);
_latitude_origin_radians = temp.Value;
_longitude_origin = longitude_origin_2;
temp = new Degree(_longitude_origin);
_longitude_origin_radians = temp.Value;
_x_origin = x_origin;
_y_origin = y_origin;
// calculate common calculation intermidiates.
_m_1 = (System.Math.Cos(_standard_parallel_1_radians) /
System.Math.Sqrt((1.0 - _ellipsoid.Eccentricity * _ellipsoid.Eccentricity *
System.Math.Pow(System.Math.Sin(_standard_parallel_1_radians), 2.0))));
_m_2 = (System.Math.Cos(_standard_parallel_2_radians) /
System.Math.Sqrt((1 - _ellipsoid.Eccentricity * _ellipsoid.Eccentricity *
System.Math.Pow(System.Math.Sin(_standard_parallel_2_radians), 2.0))));
_t_0 = (System.Math.Tan(System.Math.PI / 4.0 - _latitude_origin_radians / 2.0) /
System.Math.Pow(((1 - _ellipsoid.Eccentricity * System.Math.Sin(_latitude_origin_radians)) /
(1 + _ellipsoid.Eccentricity * System.Math.Sin(_latitude_origin_radians))), _ellipsoid.Eccentricity / 2.0));
_t_1 = (System.Math.Tan(System.Math.PI / 4.0 - _standard_parallel_1_radians / 2.0) /
System.Math.Pow(((1 - _ellipsoid.Eccentricity * System.Math.Sin(_standard_parallel_1_radians)) /
(1 + _ellipsoid.Eccentricity * System.Math.Sin(_standard_parallel_1_radians))), _ellipsoid.Eccentricity / 2.0));
_t_2 = (System.Math.Tan(System.Math.PI / 4.0 - _standard_parallel_2_radians / 2.0) /
System.Math.Pow(((1 - _ellipsoid.Eccentricity * System.Math.Sin(_standard_parallel_2_radians)) /
(1 + _ellipsoid.Eccentricity * System.Math.Sin(_standard_parallel_2_radians))), _ellipsoid.Eccentricity / 2.0));
_n = ((System.Math.Log(_m_1) - System.Math.Log(_m_2))
/ (System.Math.Log(_t_1) - System.Math.Log(_t_2)));
_g = _m_1 / (_n * System.Math.Pow(_t_1, _n));
_r_0 = _ellipsoid.SemiMajorAxis * _g * System.Math.Pow(System.Math.Abs(_t_0), _n);
}
public TileRange GetTileToLoadFor(GeoCoordinateBox bbox,
int zoom)
{
int n = (int)System.Math.Floor(System.Math.Pow(2, zoom));
Radian rad = new Degree(bbox.MaxLat);
int x_tile_min = (int)(((bbox.MinLon + 180.0f) / 360.0f) * (double)n);
int y_tile_min = (int)(
(1.0f - (System.Math.Log(System.Math.Tan(rad.Value) + (1.0f / System.Math.Cos(rad.Value))))
/ System.Math.PI) / 2f * (double)n);
rad = new Degree(bbox.MinLat);
int x_tile_max = (int)(((bbox.MaxLon + 180.0f) / 360.0f) * (double)n);
int y_tile_max = (int)(
(1.0f - (System.Math.Log(System.Math.Tan(rad.Value) + (1.0f / System.Math.Cos(rad.Value))))
/ System.Math.PI) / 2f * (double)n);
TileRange range = new TileRange();
range.XMax = x_tile_max;
range.XMin = x_tile_min;
range.YMax = y_tile_max;
range.YMin = y_tile_min;
return range;
}
/// <summary>
/// Returns the tile at the given location at the given zoom.
/// </summary>
/// <param name="location"></param>
/// <param name="zoom"></param>
/// <returns></returns>
public static Tile CreateAroundLocation(GeoCoordinate location, int zoom)
{
int n = (int)System.Math.Floor(System.Math.Pow(2, zoom));
Radian rad = new Degree(location.Latitude);
int x = (int)(((location.Longitude + 180.0f) / 360.0f) * (double)n);
int y = (int)(
(1.0f - (System.Math.Log(System.Math.Tan(rad.Value) + (1.0f / System.Math.Cos(rad.Value))))
/ System.Math.PI) / 2f * (double)n);
return new Tile(x, y, zoom);
}
