C# Class SharpMap.CoordinateSystems.Projections.AlbersProjection

Implements the Albers projection.

Implements the Albers projection. The Albers projection is most commonly used to project the United States of America. It gives the northern border with Canada a curved appearance.

The Albers Equal Area projection has the property that the area bounded by any pair of parallels and meridians is exactly reproduced between the image of those parallels and meridians in the projected domain, that is, the projection preserves the correct area of the earth though distorts direction, distance and shape somewhat.

Inheritance: MapProjection
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Public Methods

Method Description
AlbersProjection ( List parameters ) : System

Creates an instance of an Albers projection object.

The parameters this projection expects are listed below.

ItemsDescriptions latitude_of_false_originThe latitude of the point which is not the natural origin and at which grid coordinate values false easting and false northing are defined. longitude_of_false_originThe longitude of the point which is not the natural origin and at which grid coordinate values false easting and false northing are defined. latitude_of_1st_standard_parallelFor 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. latitude_of_2nd_standard_parallelFor 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. easting_at_false_originThe easting value assigned to the false origin. northing_at_false_originThe northing value assigned to the false origin.
AlbersProjection ( List parameters, bool isInverse ) : System

Creates an instance of an Albers projection object.

The parameters this projection expects are listed below.

ItemsDescriptions latitude_of_centerThe latitude of the point which is not the natural origin and at which grid coordinate values false easting and false northing are defined. longitude_of_centerThe longitude of the point which is not the natural origin and at which grid coordinate values false easting and false northing are defined. standard_parallel_1For 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. standard_parallel_2For 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. false_eastingThe easting value assigned to the false origin. false_northingThe northing value assigned to the false origin.
DegreesToMeters ( SharpMap lonlat ) : SharpMap.Geometries.Point

Converts coordinates in decimal degrees to projected meters.
Inverse ( ) : IMathTransform

Returns the inverse of this projection.
MetersToDegrees ( SharpMap p ) : SharpMap.Geometries.Point

Converts coordinates in projected meters to decimal degrees.

Private Methods

Method Description
Ro ( double a ) : double
alpha ( double lat ) : double

Method Details

AlbersProjection() public method

Creates an instance of an Albers projection object.

The parameters this projection expects are listed below.

ItemsDescriptions latitude_of_false_originThe latitude of the point which is not the natural origin and at which grid coordinate values false easting and false northing are defined. longitude_of_false_originThe longitude of the point which is not the natural origin and at which grid coordinate values false easting and false northing are defined. latitude_of_1st_standard_parallelFor 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. latitude_of_2nd_standard_parallelFor 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. easting_at_false_originThe easting value assigned to the false origin. northing_at_false_originThe northing value assigned to the false origin.
public AlbersProjection ( List parameters ) : System
parameters List List of parameters to initialize the projection.
return System

AlbersProjection() public method

Creates an instance of an Albers projection object.

The parameters this projection expects are listed below.

ItemsDescriptions latitude_of_centerThe latitude of the point which is not the natural origin and at which grid coordinate values false easting and false northing are defined. longitude_of_centerThe longitude of the point which is not the natural origin and at which grid coordinate values false easting and false northing are defined. standard_parallel_1For 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. standard_parallel_2For 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. false_eastingThe easting value assigned to the false origin. false_northingThe northing value assigned to the false origin.
public AlbersProjection ( List parameters, bool isInverse ) : System
parameters List List of parameters to initialize the projection.
isInverse bool Indicates whether the projection forward (meters to degrees or degrees to meters).
return System

DegreesToMeters() public method

Converts coordinates in decimal degrees to projected meters.
public DegreesToMeters ( SharpMap lonlat ) : SharpMap.Geometries.Point
lonlat SharpMap The point in decimal degrees.
return SharpMap.Geometries.Point

Inverse() public method

Returns the inverse of this projection.
public Inverse ( ) : IMathTransform
return IMathTransform

MetersToDegrees() public method

Converts coordinates in projected meters to decimal degrees.
public MetersToDegrees ( SharpMap p ) : SharpMap.Geometries.Point
p SharpMap Point in meters
return SharpMap.Geometries.Point