Module org.opengis.geoapi.example

Package org.opengis.example.referencing

Class SimpleDatum

Object

SimpleIdentifiedObject

SimpleDatum

All Implemented Interfaces:

Identifier, Datum, Ellipsoid, GeodeticDatum, IdentifiedObject, ReferenceIdentifier

public class SimpleDatum
extends SimpleIdentifiedObject
implements GeodeticDatum, Ellipsoid

A GeodeticDatum using the Greenwich prime meridian. This class does not make distinction between Geodetic Datum and Ellipsoid, so we implement the two interfaces by the same class.

Since:

3.1

Field Summary

Fields

Modifier and Type	Field	Description
protected final double	inverseFlattening	The inverse flattening factor.
protected final double	semiMajorAxis	The semi-major axis length, in metres.
static final GeodeticDatum	SPHERE	A spherical datum used for coordinate reference systems where datum is unknown.
static final GeodeticDatum	WGS84	The WGS84 datum.

Fields inherited from class SimpleIdentifiedObject

authority, code

Fields inherited from interface Datum

ANCHOR_POINT_KEY, DOMAIN_OF_VALIDITY_KEY, REALIZATION_EPOCH_KEY, SCOPE_KEY

Fields inherited from interface IdentifiedObject

ALIAS_KEY, IDENTIFIERS_KEY, NAME_KEY, REMARKS_KEY

Fields inherited from interface Identifier

AUTHORITY_KEY, CODE_KEY, CODESPACE_KEY, DESCRIPTION_KEY, VERSION_KEY

Constructor Summary

Constructors

Constructor	Description
SimpleDatum(Citation authority, String name, double semiMajorAxis, double inverseFlattening)	Creates a new geodetic datum for the given authority, name, and ellipsoid axis length.

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object object)	Compares this datum with the given object for equality.
Unit<Length>	getAxisUnit()	Returns the linear unit of the semi-major and semi-minor axis values.
Ellipsoid	getEllipsoid()	Returns the ellipsoid, which is represented directly by this implementation class since it does not distinguish geodetic datum and ellipsoid.
double	getInverseFlattening()	Returns the value of the inverse of the flattening constant.
PrimeMeridian	getPrimeMeridian()	Returns the prime meridian.
double	getSemiMajorAxis()	Length of the semi-major axis of the ellipsoid.
double	getSemiMinorAxis()	Length of the semi-minor axis of the ellipsoid.
boolean	isIvfDefinitive()	Indicates if the inverse flattening is definitive for this ellipsoid.
boolean	isSphere()	true if the ellipsoid is degenerate and is actually a sphere.

Methods inherited from class SimpleIdentifiedObject

getAuthority, getCode, getCodeSpace, getDomainOfValidity, getName, getScope, hashCode, toString, toWKT

Methods inherited from class Object

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

Methods inherited from interface Datum

getAnchorPoint, getDomainOfValidity, getRealizationEpoch, getScope

Methods inherited from interface IdentifiedObject

getAlias, getIdentifiers, getName, getRemarks, toWKT

Methods inherited from interface Identifier

getDescription, getVersion

Field Details

WGS84

public static final GeodeticDatum WGS84

The WGS84 datum. The semi major axis length is 6378137.0 metres and the inverse flattening factor is 298.257223563.

SPHERE

public static final GeodeticDatum SPHERE

A spherical datum used for coordinate reference systems where datum is unknown. The axis length are 6371007 metres.

semiMajorAxis

protected final double semiMajorAxis

The semi-major axis length, in metres.

See Also:

• getSemiMajorAxis()

inverseFlattening

protected final double inverseFlattening

The inverse flattening factor.

See Also:

• getInverseFlattening()

Constructor Details

SimpleDatum

public SimpleDatum(Citation authority,
 String name,
 double semiMajorAxis,
 double inverseFlattening)

Creates a new geodetic datum for the given authority, name, and ellipsoid axis length.

Parameters:

authority - organization responsible for definition of the name, or null.

name - the name of the new CRS.

semiMajorAxis - the value to be returned by getSemiMajorAxis(), in metres.

inverseFlattening - the value to be returned by getInverseFlattening().

Method Details

getEllipsoid

public Ellipsoid getEllipsoid()

Returns the ellipsoid, which is represented directly by this implementation class since it does not distinguish geodetic datum and ellipsoid.

Specified by:

getEllipsoid in interface GeodeticDatum

Returns:

the ellipsoid.

getAxisUnit

public Unit<Length> getAxisUnit()

Returns the linear unit of the semi-major and semi-minor axis values. The default implementation returns Units.METRE.

Specified by:

getAxisUnit in interface Ellipsoid

Returns:

the axis linear unit.

getSemiMajorAxis

public double getSemiMajorAxis()

Length of the semi-major axis of the ellipsoid. This is the equatorial radius in axis linear unit.

Specified by:

getSemiMajorAxis in interface Ellipsoid

Returns:

Length of semi-major axis.

getSemiMinorAxis

public double getSemiMinorAxis()

Length of the semi-minor axis of the ellipsoid. This is the polar radius in axis linear unit.

Specified by:

getSemiMinorAxis in interface Ellipsoid

Returns:

Length of semi-minor axis.

getInverseFlattening

public double getInverseFlattening()

Returns the value of the inverse of the flattening constant.

Specified by:

getInverseFlattening in interface Ellipsoid

Returns:

the inverse flattening value, or positive infinity if this ellipsoid is a sphere.

isIvfDefinitive

public boolean isIvfDefinitive()

Indicates if the inverse flattening is definitive for this ellipsoid. The default implementation returns true for if this ellipsoid is not a sphere, since the constructor of this SimpleDatum class expects a inverseFlattening value.

Specified by:

isIvfDefinitive in interface Ellipsoid

Returns:

true if the inverse flattening is definitive, or false if the polar radius is definitive.

isSphere

public boolean isSphere()

true if the ellipsoid is degenerate and is actually a sphere.

Specified by:

isSphere in interface Ellipsoid

Returns:

true if the ellipsoid is degenerate and is actually a sphere.

getPrimeMeridian

public PrimeMeridian getPrimeMeridian()

Returns the prime meridian. The default implementation returns the Greenwich prime meridian.

Specified by:

getPrimeMeridian in interface GeodeticDatum

Returns:

the prime meridian.

equals

public boolean equals(Object object)

Compares this datum with the given object for equality.

Overrides:

equals in class SimpleIdentifiedObject

Parameters:

object - The object to compare with this SimpleDatum.

Returns:

true if the given object is equal to this object.