org.cts.op.transformation

Class NTv2GridShiftTransformation

java.lang.Object

org.cts.IdentifiableComponent

org.cts.op.AbstractCoordinateOperation

org.cts.op.transformation.NTv2GridShiftTransformation

All Implemented Interfaces:

Identifiable, CoordinateOperation, GridBasedTransformation

public class NTv2GridShiftTransformation
extends AbstractCoordinateOperation
implements GridBasedTransformation

Geographic Offset by Interpolation of Gridded Data.

The relationship between some geographical 2D coordinate reference systems is available through gridded data sets of latitude and longitude offsets.

Author:

Michaël Michaud

Field Summary

Fields

Modifier and Type	Field and Description
static int	LOW_MEMORY
static int	SPEED

Fields inherited from class org.cts.op.AbstractCoordinateOperation

precision

Fields inherited from interface org.cts.Identifiable

DEFAULT, LOCAL, UNKNOWN

Constructor Summary

Constructors

Constructor and Description
NTv2GridShiftTransformation(URL ntv2_gridFile) NTv2GridShiftTransformation constructor.
NTv2GridShiftTransformation(URL ntv2_gridFile, double precision) NTv2GridShiftTransformation constructor.

Method Summary

Modifier and Type	Method and Description
static NTv2GridShiftTransformation	createNTv2GridShiftTransformation(String ntv2_gridName) Create a NTv2GridShiftTransformation from the name of the file that defined it.
String	getFromDatum() Return the short name of the datum from which the nadgrids transformation must be used.
String	getToDatum() Return the short name of the datum toward which the nadgrids transformation must be used.
CoordinateOperation	inverse() Creates the inverse CoordinateOperation.
boolean	isLoaded() Return whether the grid shift file used by this transformation is loaded or not.
void	loadGridShiftFile() Load the grid file that will be used to transform the coordinates.
boolean	setMode(int mode) Set the mode to access the grid shift file.
String	toString() Returns this Geocentric translation as a String.
double[]	transform(double[] coord) Shift geographic coordinates (in decimal degrees) by an offset interpolated in a grid.
void	unload() Unload the grid shift file used by this transformation.

Methods inherited from class org.cts.op.AbstractCoordinateOperation

getPrecision, isIdentity

Methods inherited from class org.cts.IdentifiableComponent

addAlias, addRemark, equals, getAliases, getAuthorityKey, getAuthorityName, getCode, getComponent, getIdentifier, getName, getRemarks, getShortName, hashCode, 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

SPEED

public static final int SPEED

See Also:

Constant Field Values

LOW_MEMORY

public static final int LOW_MEMORY

See Also:

Constant Field Values

Constructor Detail

NTv2GridShiftTransformation

public NTv2GridShiftTransformation(URL ntv2_gridFile,
                                   double precision)

NTv2GridShiftTransformation constructor.

Parameters:

ntv2_gridFile - file containing the description of the NTv2 grid

precision - mean precision of the geodetic transformation

NTv2GridShiftTransformation

public NTv2GridShiftTransformation(URL ntv2_gridFile)

NTv2GridShiftTransformation constructor.

Parameters:

ntv2_gridFile - file containing the description of the NTv2 grid

Method Detail

createNTv2GridShiftTransformation

public static NTv2GridShiftTransformation createNTv2GridShiftTransformation(String ntv2_gridName)
                                                                     throws URISyntaxException,
                                                                            MalformedURLException,
                                                                            NullPointerException,
                                                                            IOException

Create a NTv2GridShiftTransformation from the name of the file that defined it.

Parameters:

ntv2_gridName - the name of the file that defined the wanted grid transformation (for instance : ntf_r93.gsb).

Returns:

Throws:

URISyntaxException

MalformedURLException

NullPointerException

IOException

transform

public double[] transform(double[] coord)
                   throws IllegalCoordinateException

Shift geographic coordinates (in decimal degrees) by an offset interpolated in a grid.

Specified by:

transform in interface CoordinateOperation

Specified by:

transform in class AbstractCoordinateOperation

Parameters:

coord - coordinate to shift

Returns:

a double array containing the output coordinate

Throws:

IllegalCoordinateException - if coord is not compatible with this CoordinateOperation.

inverse

public CoordinateOperation inverse()
                            throws NonInvertibleOperationException

Creates the inverse CoordinateOperation.

Specified by:

inverse in interface CoordinateOperation

Overrides:

inverse in class AbstractCoordinateOperation

Throws:

NonInvertibleOperationException

loadGridShiftFile

public void loadGridShiftFile()
                       throws IOException

Load the grid file that will be used to transform the coordinates.

Throws:

IOException

isLoaded

public boolean isLoaded()

Return whether the grid shift file used by this transformation is loaded or not.

Returns:

unload

public void unload()
            throws IOException

Unload the grid shift file used by this transformation.

Throws:

IOException

setMode

public boolean setMode(int mode)
                throws IOException

Set the mode to access the grid shift file. If mode = 0 (SPEED), it will use an InputStream, if mode = 1 (LOW_MEMORY), it will use a RandomAccessFile. If the parameter mode is different from 0 or 1 or if it is equal to the current mode, this method will have no effect and return false.

Parameters:

mode - an integer representing a mode to access to grid shift file (see description above)

Returns:

true if a new mode has been set, false if not.

Throws:

IOException

toString

public String toString()

Returns this Geocentric translation as a String.

Overrides:

toString in class IdentifiableComponent

Returns:

getFromDatum

public String getFromDatum()

Return the short name of the datum from which the nadgrids transformation must be used.

Returns:

getToDatum

public String getToDatum()

Return the short name of the datum toward which the nadgrids transformation must be used.

Returns: