org.deegree.cs.projections
Class Projection

java.lang.Object
  org.deegree.cs.CRSIdentifiable
      org.deegree.cs.projections.Projection

All Implemented Interfaces:

Object, TypedObjectNode, CRSResource, IProjection

Direct Known Subclasses:

AzimuthalProjection, ConicProjection, CylindricalProjection

public abstract class Projection
extends CRSIdentifiable
implements IProjection

Map conversion is the process of changing the map grid coordinates (usually, but not always, Easting & Northing) of a Projected Coordinate Reference System to its corresponding geographical coordinates (Latitude & Longitude) or vice versa.

A projection is conformal if an infinitesimal small perfect circle on the earth's surface results in an infinitesimal small projected perfect circle (an ellipsoid with no eccentricity). In other words, the relative local angles about every point on the map are shown correctly.

An equal area projection can be best explained with a coin (Snyder), a coin (of any size) covers exactly the same area of the actual earth as the same coin on any other part of the map. This can only be done by distorting shape, scale and and angles of the original earth's layout.

Version:

$Revision: 29642 $, $Date: 2011-02-11 13:59:33 +0100 (Fri, 11 Feb 2011) $

Author:

Rutger Bezema, last edited by: $Author: lbuesching $

Constructor Summary

Projection(double falseNorthing, double falseEasting, javax.vecmath.Point2d naturalOrigin, IUnit units, double scale, boolean conformal, boolean equalArea, CRSResource id)
Creates a Projection.

Method Summary

abstract javax.vecmath.Point2d	doInverseProjection(IGeographicCRS underlyingCRS, double x, double y) Do an inverse projection from projected (map) coordinates to geographic coordinates.
abstract javax.vecmath.Point2d	doProjection(IGeographicCRS underlyingCRS, double lambda, double phi) The actual transform method doing a projection from geographic coordinates to map coordinates.
boolean	equals(Object other)
double	getCosphi0()
double	getEccentricity(IGeographicCRS geographicCRS)
IEllipsoid	getEllipsoid(IGeographicCRS geographicCRS)
double	getFalseEasting()
double	getFalseNorthing()
abstract String	getImplementationName()
javax.vecmath.Point2d	getNaturalOrigin()
IPrimeMeridian	getPrimeMeridian(IGeographicCRS geographicCRS)
double	getProjectionLatitude()
double	getProjectionLongitude()
double	getScale()
double	getScaleFactor(IGeographicCRS geographicCRS)
double	getSemiMajorAxis(IGeographicCRS geographicCRS)
double	getSemiMinorAxis(IGeographicCRS geographicCRS)
double	getSinphi0()
double	getSquaredEccentricity(IGeographicCRS geographicCRS)
IUnit	getUnits()
int	hashCode() Implementation as proposed by Joshua Block in Effective Java (Addison-Wesley 2001), which supplies an even distribution and is relatively fast.
boolean	isConformal()
boolean	isEqualArea()
boolean	isSpherical(IGeographicCRS geographicCRS)
void	setFalseEasting(double newFalseEasting) sets the false easting to given value.
void	setScale(double scale) Sets the old scale to the given scale, also adjusts the scaleFactor.
String	toString()

Methods inherited from class org.deegree.cs.CRSIdentifiable

addAreaOfUse, addName, checkForNullObject, checkForNullObject, checkForNullObject, getAreaOfUse, getAreaOfUseBBox, getAreasOfUse, getCode, getCodeAndName, getCodes, getDescription, getDescriptions, getId, getName, getNames, getOrignalCodeStrings, getVersion, getVersions, hasCode, hasId, hasIdOrName, setDefaultAreaOfUse, setDefaultDescription, setDefaultId, setDefaultName, setDefaultVersion

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.deegree.cs.CRSResource

addAreaOfUse, addName, getAreaOfUse, getAreaOfUseBBox, getAreasOfUse, getCode, getCodeAndName, getCodes, getDescription, getDescriptions, getName, getNames, getOrignalCodeStrings, getVersion, getVersions, hasCode, hasId, hasIdOrName, setDefaultAreaOfUse, setDefaultDescription, setDefaultId, setDefaultName, setDefaultVersion

Methods inherited from interface org.deegree.commons.tom.Object

getId

Constructor Detail

Projection

public Projection(double falseNorthing,
                  double falseEasting,
                  javax.vecmath.Point2d naturalOrigin,
                  IUnit units,
                  double scale,
                  boolean conformal,
                  boolean equalArea,
                  CRSResource id)

Creates a Projection. Caution, the given natural origin should be given in radians rather then degrees.

Parameters:

geographicCRS - which this projection uses.

falseNorthing - in given units

falseEasting - in given units

naturalOrigin - in radians longitude, latitude.

units - of the map projection

scale - at the prime meridian (e.g. 0.9996 for UTM)

conformal - if the projection is conformal

equalArea - if the projection result in an equal area map

id - an identifiable instance containing information about this projection.

Method Detail

doProjection

public abstract javax.vecmath.Point2d doProjection(IGeographicCRS underlyingCRS,
                                                   double lambda,
                                                   double phi)
                                            throws ProjectionException

The actual transform method doing a projection from geographic coordinates to map coordinates.

Specified by:

doProjection in interface IProjection

Parameters:

lambda - the longitude

phi - the latitude

Returns:

the projected Point or Point(Double.NAN, Double.NAN) if an error occurred.

Throws:

ProjectionException - if the given lamba and phi coordinates could not be projected to x and y.

doInverseProjection

public abstract javax.vecmath.Point2d doInverseProjection(IGeographicCRS underlyingCRS,
                                                          double x,
                                                          double y)
                                                   throws ProjectionException

Do an inverse projection from projected (map) coordinates to geographic coordinates.

Specified by:

doInverseProjection in interface IProjection

Parameters:

x - coordinate on the map

y - coordinate on the map

Returns:

the projected Point with x = lambda and y = phi;

Throws:

ProjectionException - if the given x and y coordinates could not be inverted to lambda and phi.

getImplementationName

public abstract String getImplementationName()

Specified by:

getImplementationName in interface IProjection

Returns:

A deegree specific name which will be used for the export of a projection.

isConformal

public final boolean isConformal()

Specified by:

isConformal in interface IProjection

Returns:

true if the projection projects conformal.

isEqualArea

public final boolean isEqualArea()

Specified by:

isEqualArea in interface IProjection

Returns:

true if the projection is projects equal Area.

getScale

public final double getScale()

Specified by:

getScale in interface IProjection

Returns:

the scale.

setScale

public void setScale(double scale)

Sets the old scale to the given scale, also adjusts the scaleFactor.

Specified by:

setScale in interface IProjection

Parameters:

scale - the new scale

getFalseEasting

public final double getFalseEasting()

Specified by:

getFalseEasting in interface IProjection

Returns:

the falseEasting.

setFalseEasting

public void setFalseEasting(double newFalseEasting)

sets the false easting to given value. (Used in for example transverse mercator, while setting the utm zone).

Specified by:

setFalseEasting in interface IProjection

Parameters:

newFalseEasting - the new false easting parameter.

getFalseNorthing

public final double getFalseNorthing()

Specified by:

getFalseNorthing in interface IProjection

Returns:

the falseNorthing.

getNaturalOrigin

public final javax.vecmath.Point2d getNaturalOrigin()

Specified by:

getNaturalOrigin in interface IProjection

Returns:

the naturalOrigin.

getUnits

public final IUnit getUnits()

Specified by:

getUnits in interface IProjection

Returns:

the units.

getPrimeMeridian

public IPrimeMeridian getPrimeMeridian(IGeographicCRS geographicCRS)

Specified by:

getPrimeMeridian in interface IProjection

Returns:

the primeMeridian of the datum.

getEllipsoid

public IEllipsoid getEllipsoid(IGeographicCRS geographicCRS)

Specified by:

getEllipsoid in interface IProjection

Returns:

the ellipsoid of the datum.

getEccentricity

public final double getEccentricity(IGeographicCRS geographicCRS)

Specified by:

getEccentricity in interface IProjection

Returns:

the eccentricity of the ellipsoid of the datum.

getSquaredEccentricity

public final double getSquaredEccentricity(IGeographicCRS geographicCRS)

Specified by:

getSquaredEccentricity in interface IProjection

Returns:

the eccentricity of the ellipsoid of the datum.

getSemiMajorAxis

public final double getSemiMajorAxis(IGeographicCRS geographicCRS)

Specified by:

getSemiMajorAxis in interface IProjection

Returns:

the semiMajorAxis (a) of the ellipsoid of the datum.

getSemiMinorAxis

public final double getSemiMinorAxis(IGeographicCRS geographicCRS)

Specified by:

getSemiMinorAxis in interface IProjection

Returns:

the semiMinorAxis (a) of the ellipsoid of the datum.

getProjectionLatitude

public final double getProjectionLatitude()

Specified by:

getProjectionLatitude in interface IProjection

Returns:

the projectionLatitude also known as central-latitude or latitude-of-origin, in Snyder referenced as phi_1 for azimuthal, phi_0 for other projections.

getProjectionLongitude

public final double getProjectionLongitude()

Specified by:

getProjectionLongitude in interface IProjection

Returns:

the projectionLongitude also known as projection-meridian or central-meridian, in Snyder referenced as lambda_0

getSinphi0

public final double getSinphi0()

Specified by:

getSinphi0 in interface IProjection

Returns:

the sinphi0, the sine of the projection latitude

getCosphi0

public final double getCosphi0()

Specified by:

getCosphi0 in interface IProjection

Returns:

the cosphi0, the cosine of the projection latitude

getScaleFactor

public double getScaleFactor(IGeographicCRS geographicCRS)

Specified by:

getScaleFactor in interface IProjection

Returns:

the scale*semimajor-axis, often revered to as R*k_0 in Snyder.

isSpherical

public boolean isSpherical(IGeographicCRS geographicCRS)

Specified by:

isSpherical in interface IProjection

Returns:

true if the ellipsoid of the datum is a sphere and not an ellipse.

equals

public boolean equals(Object other)

Overrides:

equals in class CRSIdentifiable

toString

public String toString()

Overrides:

toString in class CRSIdentifiable

hashCode

public int hashCode()

Implementation as proposed by Joshua Block in Effective Java (Addison-Wesley 2001), which supplies an even distribution and is relatively fast. It is created from field f as follows:

• boolean -- code = (f ? 0 : 1)
• byte, char, short, int -- code = (int)f
• long -- code = (int)(f ^ (f >>>32))
• float -- code = Float.floatToIntBits(f);
• double -- long l = Double.doubleToLongBits(f); code = (int)(l ^ (l >>> 32))
• all Objects, (where equals( ) calls equals( ) for this field) -- code = f.hashCode( )
• Array -- Apply above rules to each element

Combining the hash code(s) computed above: result = 37 * result + code;

Overrides:

hashCode in class CRSIdentifiable

Returns:

(int) ( result >>> 32 ) ^ (int) result;

See Also:

Object.hashCode()