ucar.unidata.geoloc.projection

Class AlbersEqualArea

java.lang.Object

ucar.unidata.geoloc.ProjectionImpl

ucar.unidata.geoloc.projection.AlbersEqualArea

All Implemented Interfaces:

Serializable, Projection

public class AlbersEqualArea
extends ProjectionImpl

Albers Equal Area Conic Projection, one or two standard parallels, spherical earth. See John Snyder, Map Projections used by the USGS, Bulletin 1532, 2nd edition (1983), p 98

Author:

Unidata Development Team

See Also:

Projection, ProjectionImpl, Serialized Form

Field Summary

Fields inherited from class ucar.unidata.geoloc.ProjectionImpl

atts, defaultMapArea, EARTH_RADIUS, INDEX_LAT, INDEX_LON, INDEX_X, INDEX_Y, isLatLon, name, PI, PI_OVER_2, PI_OVER_4, TOLERANCE

Constructor Summary

Constructors

Constructor and Description
AlbersEqualArea() Constructor with default parameters
AlbersEqualArea(double lat0, double lon0, double par1, double par2) Construct a AlbersEqualArea Projection, two standard parellels.
AlbersEqualArea(double lat0, double lon0, double par1, double par2, double falseEasting, double falseNorthing) Construct a AlbersEqualArea Projection, two standard parellels.
AlbersEqualArea(double lat0, double lon0, double par1, double par2, double falseEasting, double falseNorthing, double earth_radius) Construct a AlbersEqualArea Projection, two standard parellels.

Method Summary

Methods

Modifier and Type	Method and Description
ProjectionImpl	constructCopy() copy constructor - avoid clone !!
boolean	crossSeam(ProjectionPoint pt1, ProjectionPoint pt2) This returns true when the line between pt1 and pt2 crosses the seam.
boolean	equals(Object o) Returns true if this represents the same Projection as proj.
double	getEarthRadius() Earth radius in km
double	getFalseEasting() Get the false easting, in km.
double	getFalseNorthing() Get the false northing, in km.
double	getOriginLat() Get the origin latitude.
double	getOriginLon() Get the origin longitude.
double	getParallelOne() Get the first standard parallel
double	getParallelTwo() Get the second standard parallel
String	getProjectionTypeLabel() Get the label to be used in the gui for this type of projection
double	getScale(double lat) Get the scale at the given lat.
int	hashCode()
double[][]	latLonToProj(double[][] from, double[][] to, int latIndex, int lonIndex) Convert lat/lon coordinates to projection coordinates.
float[][]	latLonToProj(float[][] from, float[][] to, int latIndex, int lonIndex) Convert lat/lon coordinates to projection coordinates.
ProjectionPoint	latLonToProj(LatLonPoint latLon, ProjectionPointImpl result) Convert a LatLonPoint to projection coordinates
static void	main(String[] args) Test
String	paramsToString() Create a String of the parameters.
double[][]	projToLatLon(double[][] from, double[][] to) Convert lat/lon coordinates to projection coordinates.
float[][]	projToLatLon(float[][] from, float[][] to) Convert lat/lon coordinates to projection coordinates.
LatLonPoint	projToLatLon(ProjectionPoint world, LatLonPointImpl result) Convert projection coordinates to a LatLonPoint Note: a new object is not created on each call for the return value.
void	setFalseEasting(double falseEasting) Set the false_easting, in km.
void	setFalseNorthing(double falseNorthing) Set the false northing, in km.
void	setOriginLat(double lat) Set the origin latitude.
void	setOriginLon(double lon) Set the origin longitude.
void	setParallelOne(double par) Set the first standard parallel
void	setParallelTwo(double par) Set the second standard parallel
String	toString() Get a String representation of this projection.

Methods inherited from class ucar.unidata.geoloc.ProjectionImpl

addParameter, addParameter, addParameter, findProjectionParameter, getClassName, getDefaultMapArea, getDefaultMapAreaLL, getHeader, getLatLonBoundingBox, getName, getProjectionParameters, isLatLon, latLonToProj, latLonToProj, latLonToProj, latLonToProj, latLonToProj, latLonToProj, latLonToProj, latLonToProj, latLonToProjBB, projToLatLon, projToLatLon, projToLatLon, projToLatLon, projToLatLonBB, setDefaultMapArea, setName

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

AlbersEqualArea

public AlbersEqualArea()

Constructor with default parameters

AlbersEqualArea

public AlbersEqualArea(double lat0,
               double lon0,
               double par1,
               double par2)

Construct a AlbersEqualArea Projection, two standard parellels. For the one standard parellel case, set them both to the same value.

Parameters:

lat0 - lat origin of the coord. system on the projection plane

lon0 - lon origin of the coord. system on the projection plane

par1 - standard parallel 1

par2 - standard parallel 2

Throws:

IllegalArgumentException - if lat0, par1, par2 = +/-90 deg

AlbersEqualArea

public AlbersEqualArea(double lat0,
               double lon0,
               double par1,
               double par2,
               double falseEasting,
               double falseNorthing)

Construct a AlbersEqualArea Projection, two standard parellels. For the one standard parellel case, set them both to the same value.

Parameters:

lat0 - lat origin of the coord. system on the projection plane

lon0 - lon origin of the coord. system on the projection plane

par1 - standard parallel 1

par2 - standard parallel 2

falseEasting - false easting in km

falseNorthing - false easting in km

Throws:

IllegalArgumentException - if lat0, par1, par2 = +/-90 deg

AlbersEqualArea

public AlbersEqualArea(double lat0,
               double lon0,
               double par1,
               double par2,
               double falseEasting,
               double falseNorthing,
               double earth_radius)

Construct a AlbersEqualArea Projection, two standard parellels. For the one standard parellel case, set them both to the same value.

Parameters:

lat0 - lat origin of the coord. system on the projection plane

lon0 - lon origin of the coord. system on the projection plane

par1 - standard parallel 1

par2 - standard parallel 2

falseEasting - false easting in km

falseNorthing - false easting in km

earth_radius - radius of the earth in km

Throws:

IllegalArgumentException - if lat0, par1, par2 = +/-90 deg

Method Detail

constructCopy

public ProjectionImpl constructCopy()

copy constructor - avoid clone !!

Specified by:

constructCopy in class ProjectionImpl

Returns:

a copy of this Projection

equals

public boolean equals(Object o)

Description copied from class: ProjectionImpl

Returns true if this represents the same Projection as proj.

Specified by:

equals in interface Projection

Specified by:

equals in class ProjectionImpl

Parameters:

o - projection in question

Returns:

true if this represents the same Projection as proj.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

getParallelTwo

public double getParallelTwo()

Get the second standard parallel

Returns:

the second standard parallel

getParallelOne

public double getParallelOne()

Get the first standard parallel

Returns:

the first standard parallel

getOriginLon

public double getOriginLon()

Get the origin longitude.

Returns:

the origin longitude.

getOriginLat

public double getOriginLat()

Get the origin latitude.

Returns:

the origin latitude.

setParallelTwo

public void setParallelTwo(double par)

Set the second standard parallel

Parameters:

par - the second standard parallel

setParallelOne

public void setParallelOne(double par)

Set the first standard parallel

Parameters:

par - the first standard parallel

setOriginLon

public void setOriginLon(double lon)

Set the origin longitude.

Parameters:

lon - the origin longitude.

setOriginLat

public void setOriginLat(double lat)

Set the origin latitude.

Parameters:

lat - the origin latitude.

setFalseEasting

public void setFalseEasting(double falseEasting)

Set the false_easting, in km. natural_x_coordinate + false_easting = x coordinate

Parameters:

falseEasting - x offset

setFalseNorthing

public void setFalseNorthing(double falseNorthing)

Set the false northing, in km. natural_y_coordinate + false_northing = y coordinate

Parameters:

falseNorthing - y offset

getFalseEasting

public double getFalseEasting()

Get the false easting, in km.

Returns:

the false easting.

getFalseNorthing

public double getFalseNorthing()

Get the false northing, in km.

Returns:

the false northing.

getEarthRadius

public double getEarthRadius()

Earth radius in km

Returns:

Earth radius in km

getProjectionTypeLabel

public String getProjectionTypeLabel()

Get the label to be used in the gui for this type of projection

Overrides:

getProjectionTypeLabel in class ProjectionImpl

Returns:

Type label

paramsToString

public String paramsToString()

Create a String of the parameters.

Specified by:

paramsToString in interface Projection

Specified by:

paramsToString in class ProjectionImpl

Returns:

a String of the parameters

toString

public String toString()

Description copied from class: ProjectionImpl

Get a String representation of this projection.

Overrides:

toString in class ProjectionImpl

Returns:

the name of the projection. This is what gets displayed when you add the projection object to a UI widget (e.g. label, combobox)

getScale

public double getScale(double lat)

Get the scale at the given lat.

Parameters:

lat - lat to use

Returns:

scale factor at that latitude

crossSeam

public boolean crossSeam(ProjectionPoint pt1,
                ProjectionPoint pt2)

This returns true when the line between pt1 and pt2 crosses the seam. When the cone is flattened, the "seam" is lon0 +- 180.

Specified by:

crossSeam in interface Projection

Specified by:

crossSeam in class ProjectionImpl

Parameters:

pt1 - point 1

pt2 - point 2

Returns:

true when the line between pt1 and pt2 crosses the seam.

latLonToProj

public ProjectionPoint latLonToProj(LatLonPoint latLon,
                           ProjectionPointImpl result)

Convert a LatLonPoint to projection coordinates

Specified by:

latLonToProj in interface Projection

Specified by:

latLonToProj in class ProjectionImpl

Parameters:

latLon - convert from these lat, lon coordinates

result - the object to write to

Returns:

the given result

projToLatLon

public LatLonPoint projToLatLon(ProjectionPoint world,
                       LatLonPointImpl result)

Convert projection coordinates to a LatLonPoint Note: a new object is not created on each call for the return value.

Specified by:

projToLatLon in interface Projection

Specified by:

projToLatLon in class ProjectionImpl

Parameters:

world - convert from these projection coordinates

result - the object to write to

Returns:

LatLonPoint convert to these lat/lon coordinates

latLonToProj

public float[][] latLonToProj(float[][] from,
                     float[][] to,
                     int latIndex,
                     int lonIndex)

Convert lat/lon coordinates to projection coordinates.

Overrides:

latLonToProj in class ProjectionImpl

Parameters:

from - array of lat/lon coordinates: from[2][n], where from[0][i], from[1][i] is the (lat,lon) coordinate of the ith point

to - resulting array of projection coordinates, where to[0][i], to[1][i] is the (x,y) coordinate of the ith point

latIndex - index of latitude in "from"

lonIndex - index of longitude in "from"

Returns:

the "to" array.

projToLatLon

public float[][] projToLatLon(float[][] from,
                     float[][] to)

Convert lat/lon coordinates to projection coordinates.

Overrides:

projToLatLon in class ProjectionImpl

Parameters:

from - array of lat/lon coordinates: from[2][n], where (from[0][i], from[1][i]) is the (lat,lon) coordinate of the ith point

to - resulting array of projection coordinates: to[2][n] where (to[0][i], to[1][i]) is the (x,y) coordinate of the ith point

Returns:

the "to" array

latLonToProj

public double[][] latLonToProj(double[][] from,
                      double[][] to,
                      int latIndex,
                      int lonIndex)

Convert lat/lon coordinates to projection coordinates.

Overrides:

latLonToProj in class ProjectionImpl

Parameters:

from - array of lat/lon coordinates: from[2][n], where from[0][i], from[1][i] is the (lat,lon) coordinate of the ith point

to - resulting array of projection coordinates, where to[0][i], to[1][i] is the (x,y) coordinate of the ith point

latIndex - index of latitude in "from"

lonIndex - index of longitude in "from"

Returns:

the "to" array.

projToLatLon

public double[][] projToLatLon(double[][] from,
                      double[][] to)

Convert lat/lon coordinates to projection coordinates.

Overrides:

projToLatLon in class ProjectionImpl

Parameters:

from - array of lat/lon coordinates: from[2][n], where (from[0][i], from[1][i]) is the (lat,lon) coordinate of the ith point

to - resulting array of projection coordinates: to[2][n] where (to[0][i], to[1][i]) is the (x,y) coordinate of the ith point

Returns:

the "to" array

main

public static void main(String[] args)

Test

Parameters:

args - not used