org.cts.datum

Class GeodeticDatum

java.lang.Object

org.cts.IdentifiableComponent

org.cts.datum.AbstractDatum

org.cts.datum.GeodeticDatum

All Implemented Interfaces:

Datum, Identifiable

public class GeodeticDatum
extends AbstractDatum

Geodetic Datum used to determine positions relative to the Earth (longitude / latitude)

It is recommended that every GeodeticDatum has a toWGS84 SevenParameterTransformation attribute (which may eventually be a GeocentricTranslation or the Identity transformation). This operation must be the standard 3D transformation from/to the GeocentricCoordinateSystem defined by this Datum to/from the GeocentricCoordinateSystem defined by WGS84 Datum.

Moreover, a GeodeticDatum also contains a map which may contain other CoordinateOperations from the standard Geographic2DCRS or Geographic3DCRS associated with this Datum to the one associated to another Datum.

Author:

Michaël Michaud, Jules Party

Field Summary

Fields

Modifier and Type	Field and Description
static GeodeticDatum	CARTHAGE
static GeodeticDatum	ED50 European Datum 1950.
static GeodeticDatum	GGRS87
static GeodeticDatum	HERMANNSKOGEL
static GeodeticDatum	IRE65
static GeodeticDatum	NAD27
static GeodeticDatum	NAD83
static GeodeticDatum	NAD83_2011
static GeodeticDatum	NAD83_CORS96
static GeodeticDatum	NAD83_HARN
static GeodeticDatum	NTF Nouvelle Triangulation Française.
static GeodeticDatum	NTF_PARIS Nouvelle Triangulation Française (Paris).
static GeodeticDatum	NZGD49
static GeodeticDatum	OSGB36
static GeodeticDatum	POSTDAM
static GeodeticDatum	RGF93 Réseau géodésique français 1993.
static GeodeticDatum	WGS84 World Geodetic System 1984.
static GeodeticDatum	WGS84GUAD
static GeodeticDatum	WGS84MART
static GeodeticDatum	WGS84SBSM

Fields inherited from interface org.cts.Identifiable

DEFAULT, LOCAL, UNKNOWN

Method Summary

Modifier and Type	Method and Description
void	addGeocentricTransformation(GeodeticDatum targetDatum, GeocentricTransformation coordOp) Adds a Geocentric Transformation from this datum to targetDatum.
void	addGeographicTransformation(GeodeticDatum targetDatum, CoordinateOperation coordOp) Add a Geographic Transformation to another GeodeticDatum.
static GeodeticDatum	createGeodeticDatum(Identifier identifier, PrimeMeridian primeMeridian, Ellipsoid ellipsoid, GeocentricTransformation toWGS84, GeographicExtent extent, String origin, String epoch) Creates a new Datum or return a known datum if it already exists.
static GeodeticDatum	createGeodeticDatum(PrimeMeridian primeMeridian, Ellipsoid ellipsoid, GeocentricTransformation toWGS84) Creates a new Datum.
boolean	equals(Object o) Returns true if o equals this.
Ellipsoid	getEllipsoid() Return the ellipsoid of this Datum.
Set<GeocentricTransformation>	getGeocentricTransformations(GeodeticDatum targetDatum) Get available geocentric transformations to another datum.
static GeodeticDatum	getGeodeticDatum(Object id)
Set<CoordinateOperation>	getGeographicTransformations(GeodeticDatum targetDatum) Get available geographic transformations to another datum.
Set<CoordinateOperation>	getHeightTransformations(Datum datum) Get available geographic transformations to another datum.
PrimeMeridian	getPrimeMeridian() Return the PrimeMeridian of this Datum.
Set<GeodeticDatum>	getTargetDatum()
GeocentricTransformation	getToWGS84() Returns the default transformation to WGS84 of this Datum.
int	hashCode() Returns the hash code for this GeodeticDatum.
void	removeAllTransformations() Removes all transformation from this datum to others and the other way.
void	setDefaultToWGS84Operation(GeocentricTransformation toWGS84) Sets the default transformation to WGS84 in two forms : toWGS84 Geocentric transformation toWGS84 is an operation to transform geocentric coordinates based on this datum to geocentric coordinates based on WGS84 datum, generally a translation or a SevenParameterTransformation (ex.
String	toString() Returns a String representation of this GeodeticDatum.
String	toWKT() Returns a WKT representation of the geodetic datum.

Methods inherited from class org.cts.datum.AbstractDatum

getEpoch, getExtent, getOrigin

Methods inherited from class org.cts.IdentifiableComponent

addAlias, addRemark, getAliases, getAuthorityKey, getAuthorityName, getCode, getComponent, getIdentifier, getName, getRemarks, getShortName, setIdentifier, setRemarks, setShortName

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.cts.Identifiable

addAlias, addRemark, getAliases, getAuthorityKey, getAuthorityName, getCode, getName, getRemarks, getShortName, setRemarks, setShortName

Field Detail

WGS84

public static final GeodeticDatum WGS84

World Geodetic System 1984.

NTF_PARIS

public static final GeodeticDatum NTF_PARIS

Nouvelle Triangulation Française (Paris).

NTF

public static final GeodeticDatum NTF

Nouvelle Triangulation Française.

RGF93

public static final GeodeticDatum RGF93

Réseau géodésique français 1993.

ED50

public static final GeodeticDatum ED50

European Datum 1950.

WGS84GUAD

public static final GeodeticDatum WGS84GUAD

WGS84MART

public static final GeodeticDatum WGS84MART

WGS84SBSM

public static final GeodeticDatum WGS84SBSM

NAD27

public static final GeodeticDatum NAD27

NAD83

public static final GeodeticDatum NAD83

NAD83_HARN

public static final GeodeticDatum NAD83_HARN

NAD83_CORS96

public static final GeodeticDatum NAD83_CORS96

NAD83_2011

public static final GeodeticDatum NAD83_2011

GGRS87

public static final GeodeticDatum GGRS87

HERMANNSKOGEL

public static final GeodeticDatum HERMANNSKOGEL

POSTDAM

public static final GeodeticDatum POSTDAM

CARTHAGE

public static final GeodeticDatum CARTHAGE

NZGD49

public static final GeodeticDatum NZGD49

OSGB36

public static final GeodeticDatum OSGB36

IRE65

public static final GeodeticDatum IRE65

Method Detail

createGeodeticDatum

public static GeodeticDatum createGeodeticDatum(PrimeMeridian primeMeridian,
                                                Ellipsoid ellipsoid,
                                                GeocentricTransformation toWGS84)

Creates a new Datum.

Parameters:

primeMeridian - the prime meridian to use with this datum

ellipsoid - the ellipsoid to use with this datum

toWGS84 - the toWGS84 CoordinateOperation

createGeodeticDatum

public static GeodeticDatum createGeodeticDatum(Identifier identifier,
                                                PrimeMeridian primeMeridian,
                                                Ellipsoid ellipsoid,
                                                GeocentricTransformation toWGS84,
                                                GeographicExtent extent,
                                                String origin,
                                                String epoch)

Creates a new Datum or return a known datum if it already exists.

Parameters:

identifier - identifier.

primeMeridian - the prime meridian to use with this datum

ellipsoid - the ellipsoid to use with this datum

extent - this datum extension

origin - origin decription this datum

epoch - realization epoch of this datum

getPrimeMeridian

public PrimeMeridian getPrimeMeridian()

Return the PrimeMeridian of this Datum.

getEllipsoid

public Ellipsoid getEllipsoid()

Return the ellipsoid of this Datum.

setDefaultToWGS84Operation

public final void setDefaultToWGS84Operation(GeocentricTransformation toWGS84)

Sets the default transformation to WGS84 in two forms :

toWGS84 Geocentric transformation

toWGS84 is an operation to transform geocentric coordinates based on this datum to geocentric coordinates based on WGS84 datum, generally a translation or a SevenParameterTransformation (ex. Bursa-Wolf).

toWGS84 does not use PrimeMerdian nor ellipsoid parameters.

datumTransformations map (direct Geographic3D transformations)

The toWGS84 transformation is also stored in the datumTransformations map, inherited from AbstractDatum, but this time, the operation is not stored as Geocentric to Geocentric transformation but as a Geographic3D to Geographic3D transformation.

The convention for this transformation is to start from Geographic3D coordinates in radians, to include required longitude rotation, and ellipsoid transformations, and to return GeographicCoordinates in radian. Advantage is that it makes it possible to use algorithm which do not involve Geographic to Geocentric transformation like the use of NTv2 grids.

Parameters:

toWGS84 - geocentric transformation from this to geocentric WGS 84

getTargetDatum

public Set<GeodeticDatum> getTargetDatum()

addGeocentricTransformation

public void addGeocentricTransformation(GeodeticDatum targetDatum,
                                        GeocentricTransformation coordOp)

Adds a Geocentric Transformation from this datum to targetDatum. When a geocentric transformation is added to a geodetic datum, the corresponding geographic transformation is automatically built and added to geographicTransformation map.

Parameters:

targetDatum - the target datum of the transformation to add

coordOp - the transformation linking this Datum and the target datum

addGeographicTransformation

public void addGeographicTransformation(GeodeticDatum targetDatum,
                                        CoordinateOperation coordOp)

Add a Geographic Transformation to another GeodeticDatum. This transformation transforms geographic coordinates of the source geodetic datum (in radians, and based on the source prime meridian) to the target geographic datum (in radian and based on the target prime meridian)

Parameters:

targetDatum - the target geodetic datum of the transformation to add

coordOp - the geographic to geographic coordinate transformation linking this Datum and the target datum

getGeocentricTransformations

public Set<GeocentricTransformation> getGeocentricTransformations(GeodeticDatum targetDatum)

Get available geocentric transformations to another datum.

Parameters:

targetDatum - the datum that must be a target for returned transformation

Returns:

getGeographicTransformations

public Set<CoordinateOperation> getGeographicTransformations(GeodeticDatum targetDatum)

Get available geographic transformations to another datum.

The method first call getGeocentricTransformations which will try to build geocentric transformations from this datum to target datum using WGS84 pivot if no direct transformation is available. Building a new geocentric transformation to target datum will automatically build the corresponding geographic transformation and put it in the geographicTransformations map

Parameters:

targetDatum - the datum that must be a target for returned transformation

Returns:

available geographic transformations to targetDatum or an empty List if no transformation is available.

getHeightTransformations

public Set<CoordinateOperation> getHeightTransformations(Datum datum)

Get available geographic transformations to another datum. Transformations are ordered from the least precise to the most precise one.

Parameters:

datum - the datum that must be a target for returned transformation

Returns:

getToWGS84

public GeocentricTransformation getToWGS84()

Returns the default transformation to WGS84 of this Datum.

Returns:

getGeodeticDatum

public static GeodeticDatum getGeodeticDatum(Object id)

toWKT

public String toWKT()

Returns a WKT representation of the geodetic datum.

toString

public String toString()

Returns a String representation of this GeodeticDatum.

Overrides:

toString in class AbstractDatum

equals

public boolean equals(Object o)

Returns true if o equals this. o equals this if they refer to the same memory object or if they have the same identifier.

Overrides:

equals in class IdentifiableComponent

Parameters:

o - The object to compare this GeodeticDatum against

hashCode

public int hashCode()

Returns the hash code for this GeodeticDatum.

Overrides:

hashCode in class IdentifiableComponent

removeAllTransformations

public void removeAllTransformations()

Removes all transformation from this datum to others and the other way.