com.jhlabs.map.proj
Class Projection

java.lang.Object
  com.jhlabs.map.proj.Projection

All Implemented Interfaces:

Serializable, Cloneable

Direct Known Subclasses:

Apian1Projection, AugustProjection, AzimuthalProjection, BaconProjection, BipolarProjection, ConicProjection, CylindricalProjection, HatanoProjection, LagrangeProjection, LandsatProjection, LarriveeProjection, LaskowskiProjection, LinearProjection, ModifiedAzimuthalProjection, NicolosiProjection, NullProjection, OrteliusProjection, PerspectiveProjection, PolyconicProjection, PseudoCylindricalProjection, RectangularPolyconicProjection, VanDerGrintenProjection

public abstract class Projection
extends Object
implements Cloneable, Serializable

The superclass for all map projections Changes by Bernhard Jenny 18 May 2010: Added Serializable interface, added abstract keyword, added binarySearchInverse, added transform and inverseTransform with lon/lat as doubles. 25 October 2010: Made all setters and getters dealing with degrees final and calling the versions using radians. Derived classes now only need to overwrite a single getter or setter (if overwriting is at all necessary).

See Also:

Serialized Form

Field Summary

protected double	a The equator radius
protected static double	DTR
protected double	e The eccentricity
protected Ellipsoid	ellipsoid The ellipsoid used by this projection
protected static double	EPS10
protected double	es The eccentricity squared
protected double	falseEasting The false Easting of this projection
protected double	falseNorthing The false Northing of this projection
protected double	fromMetres Conversion factor from metres to whatever units the projection uses.
protected boolean	geocentric True if this projection is geocentric
protected double	maxLatitude The maximum latitude of the bounds of this projection
protected double	maxLongitude The maximum longitude of the bounds of this projection.
protected double	minLatitude The minimum latitude of the bounds of this projection
protected double	minLongitude The minimum longitude of the bounds of this projection.
protected String	name The name of this projection
protected double	one_es 1-(eccentricity squared)
protected double	projectionLatitude The latitude of the centre of projection
protected double	projectionLongitude The longitude of the centre of projection
protected double	rone_es 1/(1-(eccentricity squared))
protected static double	RTD
protected double	scaleFactor The projection scale factor
protected boolean	spherical True if this projection is using a sphere (es == 0)
protected double	trueScaleLatitude The latitude of true scale.

Constructor Summary

protected

Projection()

Method Summary

protected void	binarySearchInverse(double x, double y, double lon, double lat, Point2D.Double lp) Compute the inverse projection by a binary search.
protected void	binarySearchInverse(double x, double y, Point2D.Double lp) Compute the inverse projection by a binary search.
Object	clone()
Ellipsoid	getEllipsoid()
int	getEPSGCode() Returns the ESPG code for this projection, or 0 if unknown.
double	getEquatorRadius()
double	getFalseEasting()
double	getFalseNorthing()
double	getFromMetres()
double	getMaxLatitude()
double	getMaxLatitudeDegrees()
double	getMaxLongitude()
double	getMaxLongitudeDegrees()
double	getMinLatitude()
double	getMinLatitudeDegrees()
double	getMinLongitude()
double	getMinLongitudeDegrees()
String	getName()
String	getPROJ4Description() Get a string which describes this projection in PROJ.4 format.
String	getProjectionDescription() Returns a human readable description of this projection in telegram style.
double	getProjectionLatitude()
double	getProjectionLatitudeDegrees()
double	getProjectionLongitude()
double	getProjectionLongitudeDegrees()
double	getScaleFactor()
double	getTrueScaleLatitude()
double	getTrueScaleLatitudeDegrees()
boolean	hasInverse() Returns true if this projection has an inverse
void	initialize() Initialize the projection.
boolean	inside(double lon, double lat) Returns true if the given lat/lon point is visible in this projection.
void	inverseTransform(double[] srcPoints, int srcOffset, double[] dstPoints, int dstOffset, int numPoints) Inverse-project a number of points (in metres), producing a lat/long result in degrees
Point2D.Double	inverseTransform(Point2D.Double src, Point2D.Double dst) Inverse-project a point (in metres), producing a lat/long result in degrees
Rectangle2D	inverseTransform(Rectangle2D r) Finds the smallest lat/long rectangle wholly inside the given view rectangle.
void	inverseTransformRadians(double[] srcPoints, int srcOffset, double[] dstPoints, int dstOffset, int numPoints) Inverse-project a number of points (in metres), producing a lat/long result in radians
void	inverseTransformRadians(double srcX, double srcY, Point2D.Double dst) Inverse-project a point (in meters), producing a lat/long result in radians.
Point2D.Double	inverseTransformRadians(Point2D.Double src, Point2D.Double dst) Inverse-project a point (in metres), producing a lat/long result in radians
boolean	isConformal() Returns true if this projection is conformal
boolean	isEqualArea() Returns true if this projection is equal area
boolean	isRectilinear() Returns true if lat/long lines form a rectangular grid for this projection.
static void	main(String[] args)
boolean	parallelsAreParallel() Returns true if latitude lines are parallel for this projection
Point2D.Double	project(double x, double y, Point2D.Double dst) The method which actually does the projection.
Point2D.Double	projectInverse(double x, double y, Point2D.Double dst) The method which actually does the inverse projection.
void	setEllipsoid(Ellipsoid ellipsoid)
void	setFalseEasting(double falseEasting) Set the false Easting in projected units.
void	setFalseNorthing(double falseNorthing) Set the false Northing in projected units.
void	setFromMetres(double fromMetres) Set the conversion factor from metres to projected units.
void	setMaxLatitude(double maxLatitude) Set the maximum latitude.
void	setMaxLongitude(double maxLongitude)
void	setMaxLongitudeDegrees(double maxLongitude)
void	setMinLatitude(double minLatitude) Set the minimum latitude.
void	setMinLongitude(double minLongitude)
void	setMinLongitudeDegrees(double minLongitude)
void	setName(String name) Set the name of this projection.
void	setProjectionLatitude(double projectionLatitude) Set the projection latitude in radians.
void	setProjectionLatitudeDegrees(double projectionLatitude) Set the projection latitude in degrees.
void	setProjectionLongitude(double projectionLongitude) Set the projection longitude in radians.
void	setProjectionLongitudeDegrees(double projectionLongitude) Set the projection longitude in degrees.
void	setScaleFactor(double scaleFactor) Set the projection scale factor.
void	setTrueScaleLatitude(double trueScaleLatitude) Set the latitude of true scale in radians.
void	setTrueScaleLatitudeDegrees(double trueScaleLatitude) Set the latitude of true scale in degrees.
void	testBinarySearchInverse()
String	toString()
void	transform(double[] srcPoints, int srcOffset, double[] dstPoints, int dstOffset, int numPoints) Project a number of lat/long points (in degrees), producing a result in metres
Point2D.Double	transform(double lon, double lat, Point2D.Double dst) Project a lon/lat point (in degrees), producing a result in metres.
Point2D.Double	transform(Point2D.Double src, Point2D.Double dst) Project a lat/long point (in degrees), producing a result in metres
Rectangle2D	transform(Rectangle2D r) Transform a bounding box.
void	transformRadians(double[] srcPoints, int srcOffset, double[] dstPoints, int dstOffset, int numPoints) Project a number of lat/long points (in radians), producing a result in metres
Point2D.Double	transformRadians(double lon, double lat, Point2D.Double dst) Project a lon/lat point (in degrees), producing a result in metres.
Point2D.Double	transformRadians(Point2D.Double src, Point2D.Double dst) Project a lat/long point, producing a result in metres

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

minLatitude

protected double minLatitude

The minimum latitude of the bounds of this projection

minLongitude

protected double minLongitude

The minimum longitude of the bounds of this projection. This is relative to the projection centre.

maxLatitude

protected double maxLatitude

The maximum latitude of the bounds of this projection

maxLongitude

protected double maxLongitude

The maximum longitude of the bounds of this projection. This is relative to the projection centre.

projectionLatitude

protected double projectionLatitude

The latitude of the centre of projection

projectionLongitude

protected double projectionLongitude

The longitude of the centre of projection

scaleFactor

protected double scaleFactor

The projection scale factor

falseEasting

protected double falseEasting

The false Easting of this projection

falseNorthing

protected double falseNorthing

The false Northing of this projection

trueScaleLatitude

protected double trueScaleLatitude

The latitude of true scale. Only used by specific projections.

a

protected double a

The equator radius

e

protected double e

The eccentricity

es

protected double es

The eccentricity squared

one_es

protected double one_es

1-(eccentricity squared)

rone_es

protected double rone_es

1/(1-(eccentricity squared))

ellipsoid

protected Ellipsoid ellipsoid

The ellipsoid used by this projection

spherical

protected boolean spherical

True if this projection is using a sphere (es == 0)

geocentric

protected boolean geocentric

True if this projection is geocentric

name

protected String name

The name of this projection

fromMetres

protected double fromMetres

Conversion factor from metres to whatever units the projection uses.

EPS10

protected static final double EPS10

See Also:

Constant Field Values

RTD

protected static final double RTD

See Also:

Constant Field Values

DTR

protected static final double DTR

See Also:

Constant Field Values

Constructor Detail

Projection

protected Projection()

Method Detail

clone

public Object clone()

Overrides:

clone in class Object

transform

public Point2D.Double transform(Point2D.Double src,
                                Point2D.Double dst)

Project a lat/long point (in degrees), producing a result in metres

transform

public final Point2D.Double transform(double lon,
                                      double lat,
                                      Point2D.Double dst)

Project a lon/lat point (in degrees), producing a result in metres. Important: unlike the other variations of tansform, this implementation always normalizes the longitude, even if projectionLongitude is 0. This is useful for projecting line features crossing +/180 degree of longitude. Bernhard Jenny, May 2010.

transformRadians

public Point2D.Double transformRadians(Point2D.Double src,
                                       Point2D.Double dst)

Project a lat/long point, producing a result in metres

transformRadians

public final Point2D.Double transformRadians(double lon,
                                             double lat,
                                             Point2D.Double dst)

Project a lon/lat point (in degrees), producing a result in metres. Important: unlike the other variations of tansform, this implementation always normalizes the longitude, even if projectionLongitude is 0. This is useful for projecting line features crossing +/180 degree of longitude. Bernhard Jenny, May 2010.

project

public Point2D.Double project(double x,
                              double y,
                              Point2D.Double dst)

The method which actually does the projection. This should be overridden for all projections.

Parameters:

x - Longitude in radians.

y - Latitude in radians.

dst - The projected point.

Returns:

The projected point, identical to parameter dst.

transform

public void transform(double[] srcPoints,
                      int srcOffset,
                      double[] dstPoints,
                      int dstOffset,
                      int numPoints)

Project a number of lat/long points (in degrees), producing a result in metres

transformRadians

public void transformRadians(double[] srcPoints,
                             int srcOffset,
                             double[] dstPoints,
                             int dstOffset,
                             int numPoints)

Project a number of lat/long points (in radians), producing a result in metres

inverseTransform

public Point2D.Double inverseTransform(Point2D.Double src,
                                       Point2D.Double dst)

Inverse-project a point (in metres), producing a lat/long result in degrees

inverseTransformRadians

public Point2D.Double inverseTransformRadians(Point2D.Double src,
                                              Point2D.Double dst)

Inverse-project a point (in metres), producing a lat/long result in radians

inverseTransformRadians

public void inverseTransformRadians(double srcX,
                                    double srcY,
                                    Point2D.Double dst)

Inverse-project a point (in meters), producing a lat/long result in radians. Added by Bernhard Jenny, May 2007.

projectInverse

public Point2D.Double projectInverse(double x,
                                     double y,
                                     Point2D.Double dst)

The method which actually does the inverse projection. This should be overridden for all projections.

inverseTransform

public void inverseTransform(double[] srcPoints,
                             int srcOffset,
                             double[] dstPoints,
                             int dstOffset,
                             int numPoints)

Inverse-project a number of points (in metres), producing a lat/long result in degrees

inverseTransformRadians

public void inverseTransformRadians(double[] srcPoints,
                                    int srcOffset,
                                    double[] dstPoints,
                                    int dstOffset,
                                    int numPoints)

Inverse-project a number of points (in metres), producing a lat/long result in radians

inverseTransform

public Rectangle2D inverseTransform(Rectangle2D r)

Finds the smallest lat/long rectangle wholly inside the given view rectangle. This is only a rough estimate.

main

public static void main(String[] args)

testBinarySearchInverse

public void testBinarySearchInverse()

binarySearchInverse

protected void binarySearchInverse(double x,
                                   double y,
                                   Point2D.Double lp)

Compute the inverse projection by a binary search. Use this method carefully! It is slow and only an approximation for projections that do not provide their own projectInverse method. Added by Bernhard Jenny, 18 May 2010.

Parameters:

x - The projected x coordinate relative to the unary sphere.

y - The projected y coordinate relative to the unary sphere.

lp - A point that will receive the result.

binarySearchInverse

protected void binarySearchInverse(double x,
                                   double y,
                                   double lon,
                                   double lat,
                                   Point2D.Double lp)

Compute the inverse projection by a binary search. Use this method carfully! It is slow and only an approximation for projections that do not provide their own projectInverse method. Added by Bernhard Jenny, 18 May 2010.

Parameters:

x - The projected x coordinate relative to the unary sphere.

y - The projected y coordinate relative to the unary sphere.

lon - An approximation of the longitude in radians.

lat - An approximation of the latitude in radians.

lp - A point that will receive the result.

transform

public Rectangle2D transform(Rectangle2D r)

Transform a bounding box. This is only a rough estimate.

isConformal

public boolean isConformal()

Returns true if this projection is conformal

isEqualArea

public boolean isEqualArea()

Returns true if this projection is equal area

hasInverse

public boolean hasInverse()

Returns true if this projection has an inverse

isRectilinear

public boolean isRectilinear()

Returns true if lat/long lines form a rectangular grid for this projection. This is generally only the case for cylindrical projections, but not for oblique cylindrical projections.

parallelsAreParallel

public boolean parallelsAreParallel()

Returns true if latitude lines are parallel for this projection

inside

public boolean inside(double lon,
                      double lat)

Returns true if the given lat/lon point is visible in this projection.

Parameters:

x - longitude in degrees.

y - latitude in degrees.

Returns:

setName

public void setName(String name)

Set the name of this projection.

getName

public String getName()

getProjectionDescription

public String getProjectionDescription()

Returns a human readable description of this projection in telegram style.

Returns:

getPROJ4Description

public String getPROJ4Description()

Get a string which describes this projection in PROJ.4 format.

toString

public String toString()

Overrides:

toString in class Object

setMinLatitude

public void setMinLatitude(double minLatitude)

Set the minimum latitude. This is only used for Shape clipping and doesn't affect projection.

getMinLatitude

public double getMinLatitude()

setMaxLatitude

public void setMaxLatitude(double maxLatitude)

Set the maximum latitude. This is only used for Shape clipping and doesn't affect projection.

getMaxLatitude

public double getMaxLatitude()

getMaxLatitudeDegrees

public final double getMaxLatitudeDegrees()

getMinLatitudeDegrees

public final double getMinLatitudeDegrees()

setMinLongitude

public void setMinLongitude(double minLongitude)

getMinLongitude

public double getMinLongitude()

setMinLongitudeDegrees

public final void setMinLongitudeDegrees(double minLongitude)

getMinLongitudeDegrees

public final double getMinLongitudeDegrees()

setMaxLongitude

public void setMaxLongitude(double maxLongitude)

getMaxLongitude

public double getMaxLongitude()

setMaxLongitudeDegrees

public final void setMaxLongitudeDegrees(double maxLongitude)

getMaxLongitudeDegrees

public final double getMaxLongitudeDegrees()

setProjectionLatitude

public void setProjectionLatitude(double projectionLatitude)

Set the projection latitude in radians.

getProjectionLatitude

public double getProjectionLatitude()

setProjectionLatitudeDegrees

public final void setProjectionLatitudeDegrees(double projectionLatitude)

Set the projection latitude in degrees.

getProjectionLatitudeDegrees

public final double getProjectionLatitudeDegrees()

setProjectionLongitude

public void setProjectionLongitude(double projectionLongitude)

Set the projection longitude in radians.

getProjectionLongitude

public double getProjectionLongitude()

setProjectionLongitudeDegrees

public final void setProjectionLongitudeDegrees(double projectionLongitude)

Set the projection longitude in degrees.

getProjectionLongitudeDegrees

public double getProjectionLongitudeDegrees()

setTrueScaleLatitude

public void setTrueScaleLatitude(double trueScaleLatitude)

Set the latitude of true scale in radians. This is only used by certain projections.

getTrueScaleLatitude

public double getTrueScaleLatitude()

setTrueScaleLatitudeDegrees

public final void setTrueScaleLatitudeDegrees(double trueScaleLatitude)

Set the latitude of true scale in degrees. This is only used by certain projections.

getTrueScaleLatitudeDegrees

public final double getTrueScaleLatitudeDegrees()

setFalseNorthing

public void setFalseNorthing(double falseNorthing)

Set the false Northing in projected units.

getFalseNorthing

public double getFalseNorthing()

setFalseEasting

public void setFalseEasting(double falseEasting)

Set the false Easting in projected units.

getFalseEasting

public double getFalseEasting()

setScaleFactor

public void setScaleFactor(double scaleFactor)

Set the projection scale factor. This is set to 1 by default.

getScaleFactor

public double getScaleFactor()

getEquatorRadius

public double getEquatorRadius()

setFromMetres

public void setFromMetres(double fromMetres)

Set the conversion factor from metres to projected units. This is set to 1 by default.

getFromMetres

public double getFromMetres()

setEllipsoid

public void setEllipsoid(Ellipsoid ellipsoid)

getEllipsoid

public Ellipsoid getEllipsoid()

getEPSGCode

public int getEPSGCode()

Returns the ESPG code for this projection, or 0 if unknown.

initialize

public void initialize()

Initialize the projection. This should be called after setting parameters and before using the projection. This is for performance reasons as initialization may be expensive.