Class NTV2

java.lang.Object

org.locationtech.proj4j.datum.NTV2

public final class NTV2
extends Object

Parser for the "National Transformation" v2 format Very basic implementation: only files with 1 subfile are supported, gridshift type is supposed to be in seconds Header structure:

0        8        16
|NUM_OREC|iiii    |
|NUM_SREC|iiii    |
|NUM_FILE|iiii    |
|GS_TYPE |ssssssss|
|VERSION |ssssssss|
|SYSTEM_F|ssssssss|
|SYSTEM_T|ssssssss|
|MAJOR_F |dddddddd|
|MINOR_F |dddddddd|
|MAJOR_T |dddddddd|
|MINOR_T |dddddddd|

Subfile header:

|SUB_NAME|ssssssss|
|PARENT  |ssssssss|
|CREATED |ssssssss|
|UPDATED |ssssssss|
|S_LAT   |dddddddd|
|N_LAT   |dddddddd|
|E_LONG  |dddddddd|
|W_LONG  |dddddddd|
|LAT_INC |dddddddd|
|LONG_INC|dddddddd|
|GS_COUNT|iiii    |

Grid shift records

|dddd|dddd|dddd|dddd|

End of File record

|END     |dddddddd|

Field Summary

Fields

Modifier and Type	Field	Description
private static final int	E_LONG
private static final int	HEADER_SIZE
private static final int	LAT_INC
private static final int	LONG_INC
private static final byte[]	MAGIC
private static final int	N_LAT
private static final int	NUM_OREC
private static final int	S_LAT
private static final double	SEC_RAD
private static final int	SUB_HEADER_SIZE
private static final int	VALUES_PER_CELL
private static final int	W_LONG

Constructor Summary

Constructors

Constructor	Description
NTV2()

Method Summary

Modifier and Type	Method	Description
private static double	doubleFromBytes(byte[] b, int offset, ByteOrder order)
private static ByteOrder	guessByteOrder(byte[] header)	Guess byte order / endianness by checking first bytes in header
static Grid.ConversionTable	init(DataInputStream instream)	Initialize conversion table
static void	load(DataInputStream instream, Grid grid)	Load grid(sub)file into grid
static boolean	testHeader(byte[] header)	Use header to check file type

Methods inherited from class Object

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

Field Details

MAGIC

private static final byte[] MAGIC

SEC_RAD

private static final double SEC_RAD

See Also:

• Constant Field Values

HEADER_SIZE

private static final int HEADER_SIZE

See Also:

• Constant Field Values

SUB_HEADER_SIZE

private static final int SUB_HEADER_SIZE

See Also:

• Constant Field Values

VALUES_PER_CELL

private static final int VALUES_PER_CELL

See Also:

• Constant Field Values

NUM_OREC

private static final int NUM_OREC

See Also:

• Constant Field Values

S_LAT

private static final int S_LAT

See Also:

• Constant Field Values

N_LAT

private static final int N_LAT

See Also:

• Constant Field Values

E_LONG

private static final int E_LONG

See Also:

• Constant Field Values

W_LONG

private static final int W_LONG

See Also:

• Constant Field Values

LAT_INC

private static final int LAT_INC

See Also:

• Constant Field Values

LONG_INC

private static final int LONG_INC

See Also:

• Constant Field Values

Constructor Details

NTV2

public NTV2()

Method Details

testHeader

public static boolean testHeader(byte[] header)

Use header to check file type

Parameters:

header -

Returns:

true if format is NTv2

init

public static Grid.ConversionTable init(DataInputStream instream)
                                 throws IOException

Initialize conversion table

Parameters:

instream -

Returns:

Throws:

IOException

load

public static void load(DataInputStream instream,
 Grid grid)
                 throws IOException

Load grid(sub)file into grid

Parameters:

instream -

grid -

Throws:

IOException

guessByteOrder

private static ByteOrder guessByteOrder(byte[] header)

Guess byte order / endianness by checking first bytes in header

Parameters:

header -

Returns:

endianness

doubleFromBytes

private static double doubleFromBytes(byte[] b,
 int offset,
 ByteOrder order)