org.osgeo.proj4j.datum

Class Datum

java.lang.Object

org.osgeo.proj4j.datum.Datum

public class Datum
extends Object

A class representing a geodetic datum.

A geodetic datum consists of a set of reference points on or in the Earth, and a reference Ellipsoid giving an approximation to the true shape of the geoid.

In order to transform between two geodetic points specified on different datums, it is necessary to transform between the two datums. There are various ways in which this datum conversion may be specified:

• A 3-parameter conversion
• A 7-parameter conversion
• A grid-shift conversion

In order to be able to transform between any two datums, the parameter-based transforms are provided as a transform to the common WGS84 datum. The WGS transforms of two arbitrary datum transforms can be concatenated to provide a transform between the two datums.

Notable datums in common use include NAD83 and WGS84.

Field Summary

Fields

Modifier and Type	Field and Description
static Datum	CARTHAGE
static double	ELLIPSOID_E2_TOLERANCE
static Datum	GGRS87
static Datum	HERMANNSKOGEL
static Datum	IRE65
static Datum	NAD27
static Datum	NAD83
static Datum	NZGD49
static Datum	OSEB36
static Datum	POTSDAM
static int	TYPE_3PARAM
static int	TYPE_7PARAM
static int	TYPE_GRIDSHIFT
static int	TYPE_UNKNOWN
static int	TYPE_WGS84
static Datum	WGS84

Constructor Summary

Constructors

Constructor and Description
Datum(String code, double[] transform, Ellipsoid ellipsoid, String name)
Datum(String code, double deltaX, double deltaY, double deltaZ, double rx, double ry, double rz, double mbf, Ellipsoid ellipsoid, String name)
Datum(String code, double deltaX, double deltaY, double deltaZ, Ellipsoid ellipsoid, String name)
Datum(String code, String transformSpec, Ellipsoid ellipsoid, String name)

Method Summary

Modifier and Type	Method and Description
String	getCode()
Ellipsoid	getEllipsoid()
String	getName()
double[]	getTransformToWGS84()
int	getTransformType()
boolean	hasTransformToWGS84()
boolean	isEqual(Datum datum) Tests if this is equal to another Datum.
String	toString()
void	transformFromGeocentricToWgs84(ProjCoordinate p)
void	transformToGeocentricFromWgs84(ProjCoordinate p)

Methods inherited from class java.lang.Object

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

Field Detail

TYPE_UNKNOWN

public static final int TYPE_UNKNOWN

See Also:

Constant Field Values

TYPE_WGS84

public static final int TYPE_WGS84

See Also:

Constant Field Values

TYPE_3PARAM

public static final int TYPE_3PARAM

See Also:

Constant Field Values

TYPE_7PARAM

public static final int TYPE_7PARAM

See Also:

Constant Field Values

TYPE_GRIDSHIFT

public static final int TYPE_GRIDSHIFT

See Also:

Constant Field Values

WGS84

public static final Datum WGS84

GGRS87

public static final Datum GGRS87

NAD83

public static final Datum NAD83

NAD27

public static final Datum NAD27

POTSDAM

public static final Datum POTSDAM

CARTHAGE

public static final Datum CARTHAGE

HERMANNSKOGEL

public static final Datum HERMANNSKOGEL

IRE65

public static final Datum IRE65

NZGD49

public static final Datum NZGD49

OSEB36

public static final Datum OSEB36

ELLIPSOID_E2_TOLERANCE

public static final double ELLIPSOID_E2_TOLERANCE

See Also:

Constant Field Values

Constructor Detail

Datum

public Datum(String code,
             String transformSpec,
             Ellipsoid ellipsoid,
             String name)

Datum

public Datum(String code,
             double deltaX,
             double deltaY,
             double deltaZ,
             Ellipsoid ellipsoid,
             String name)

Datum

public Datum(String code,
             double deltaX,
             double deltaY,
             double deltaZ,
             double rx,
             double ry,
             double rz,
             double mbf,
             Ellipsoid ellipsoid,
             String name)

Datum

public Datum(String code,
             double[] transform,
             Ellipsoid ellipsoid,
             String name)

Method Detail

getCode

public String getCode()

getName

public String getName()

toString

public String toString()

Overrides:

toString in class Object

getEllipsoid

public Ellipsoid getEllipsoid()

getTransformToWGS84

public double[] getTransformToWGS84()

getTransformType

public int getTransformType()

hasTransformToWGS84

public boolean hasTransformToWGS84()

isEqual

public boolean isEqual(Datum datum)

Tests if this is equal to another Datum.

Datums are considered to be equal iff:

• their transforms are equal
• OR their ellipsoids are (approximately) equal

Parameters:

datum -

Returns:

transformFromGeocentricToWgs84

public void transformFromGeocentricToWgs84(ProjCoordinate p)

transformToGeocentricFromWgs84

public void transformToGeocentricFromWgs84(ProjCoordinate p)