org.gridfour.gvrs

Class GvrsElementIntCodedFloat

java.lang.Object

org.gridfour.gvrs.GvrsElement

org.gridfour.gvrs.GvrsElementIntCodedFloat

public class GvrsElementIntCodedFloat
extends GvrsElement

Provides a concrete definition of the GvrsElement class to access four-byte floating-point values encoded as integers.

Method Summary

Modifier and Type	Method and Description
float	getFillValue() Gets the value that is assigned to all raster cells that have not been otherwise populated.
int	getFillValueInt() Gets the value that is assigned to all raster cells that have not been otherwise populated.
float	getMaxValue() Gets the maximum floating-point value specified for the range of this instance.
int	getMaxValueInt() Gets the maximum value specified for the range of this instance.
float	getMinValue() Gets the minimum floating-point value specified for the range of this instance.
int	getMinValueInt() Gets the minimum value specified for the range of this instance.
boolean	isValueSupported(float value)
float	mapIntegerToValue(int integerCode) Converts a coded integer to its associated floating-point value based on the scale and offset parameters set for this instance.
int	mapValueToInteger(float value) Converts a floating-point value to its associated integer code based on the scale and offset parameters set for this instance.
float	readValue(GridPoint gridPoint) Reads a floating-point value from the GVRS raster file.
float	readValue(int row, int column) Reads a floating-point value from the GVRS raster file.
int	readValueInt(GridPoint gridPoint) Reads an integer value from the GVRS raster file.
int	readValueInt(int row, int column) Read the encoded integer value from the GvrsFile.
String	toString()
void	writeValue(GridPoint gridPoint, float value) Write a floating-point value to the GVRS raster file.
void	writeValue(int row, int col, float value) Write a floating-point value to the GVRS raster file.
void	writeValueInt(GridPoint gridPoint, int value) Write an integer value in the GVRS raster file.
void	writeValueInt(int row, int column, int value) Stores an integer value in the GvrsFile; while this method is provided for compatibility with the GvrsElement base class, its use requires special handling.

Methods inherited from class org.gridfour.gvrs.GvrsElement

getDataType, getDescription, getLabel, getName, getUnitOfMeasure, isContinuous, readBlock, readBlockInt

Methods inherited from class java.lang.Object

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

Method Detail

readValueInt

public int readValueInt(int row,
                        int column)
                 throws IOException

Read the encoded integer value from the GvrsFile. If no data exists for the specified row and column, the fill value will be returned.

Note: This class is unusual for GVRS because the integer return value for this method is not a simple casting of the floating point value. Rather, this method returns the integer-coded representation of the floating-point value.

Specified by:

readValueInt in class GvrsElement

Parameters:

row - a positive value in the range defined by the file specifications.

column - a positive value in the range defined by the file specifications.

Returns:

an integer value in the integer-coded-float format.

Throws:

IOException - in the event of a non-recoverable I/O exception.

writeValueInt

public void writeValueInt(int row,
                          int column,
                          int value)
                   throws IOException

Stores an integer value in the GvrsFile; while this method is provided for compatibility with the GvrsElement base class, its use requires special handling.

Note: This class is unusual for GVRS because the value stored by this method is not a simple equivalent of the floating point value. Rather, this method treats the input integer value as the integer code for an associated floating-point value.

Specified by:

writeValueInt in class GvrsElement

Parameters:

row - a positive value in the range defined by the file specifications.

column - a positive value in the range defined by the file specifications.

value - an integer value in the integer-coded-float format.

Throws:

IOException - in the event of a non-recoverable I/O exception.

readValue

public float readValue(int row,
                       int column)
                throws IOException

Description copied from class: GvrsElement

Reads a floating-point value from the GVRS raster file. If no data exists for the specified row and column, the fill value will be returned.

Specified by:

readValue in class GvrsElement

Parameters:

row - a positive value in the range defined by the file specifications.

column - a positive value in the range defined by the file specifications.

Returns:

an floating-point value or the fill value if there is no data stored at the specified row and column

Throws:

IOException - in the event of a non-recoverable I/O exception.

writeValue

public void writeValue(int row,
                       int col,
                       float value)
                throws IOException

Description copied from class: GvrsElement

Write a floating-point value to the GVRS raster file. Because write operations are buffered, this data may be retained in memory for some time before actually being written to the file. However, any data lingering in memory will be recorded when the flush() or close() methods are called.

The value Float.NaN is reserved for the representation of null data.

Specified by:

writeValue in class GvrsElement

Parameters:

row - a positive value in the range defined by the file specifications.

col - a positive value in the range defined by the file specifications.

value - an floating-point value.

Throws:

IOException - in the event of an unrecoverable I/O exception.

readValue

public float readValue(GridPoint gridPoint)
                throws IOException

Description copied from class: GvrsElement

Reads a floating-point value from the GVRS raster file. If no data exists for the coordinates (row and column) specified by the GridPoint instance, the fill value will be returned.

Specified by:

readValue in class GvrsElement

Parameters:

gridPoint - a valid instance

Returns:

an floating-point value or the fill value if there is no data stored at the specified row and column

Throws:

IOException - in the event of a non-recoverable I/O exception.

readValueInt

public int readValueInt(GridPoint gridPoint)
                 throws IOException

Description copied from class: GvrsElement

Reads an integer value from the GVRS raster file. If no data exists for the coordinates (row and column) specified by the GridPoint instance, the fill value will be returned.

Specified by:

readValueInt in class GvrsElement

Parameters:

gridPoint - a valid instance

Returns:

an integer value stored at the specified row and column

Throws:

IOException - in the event of a non-recoverable I/O exception.

writeValue

public void writeValue(GridPoint gridPoint,
                       float value)
                throws IOException

Description copied from class: GvrsElement

Write a floating-point value to the GVRS raster file. Because write operations are buffered, this data may be retained in memory for some time before actually being written to the file. However, any data lingering in memory will be recorded when the flush() or close() methods are called.

The value Float.NaN is reserved for the representation of null data.

Specified by:

writeValue in class GvrsElement

Parameters:

gridPoint - a valid instance giving coordinates within the limits of the grid.

value - an floating-point value.

Throws:

IOException - in the event of an unrecoverable I/O exception.

writeValueInt

public void writeValueInt(GridPoint gridPoint,
                          int value)
                   throws IOException

Description copied from class: GvrsElement

Write an integer value in the GVRS raster file. Because write operations are buffered, this data may be retained in memory for some time before actually being written to the file. However, any data lingering in memory will be recorded when the flush() or close() methods are called.

The value GvrsFileConstants.NULL_DATA_CODE is reserved for the representation of null data.

Specified by:

writeValueInt in class GvrsElement

Parameters:

gridPoint - a valid instance giving coordinates within the dimensions of the grid.

value - an integer value.

Throws:

IOException - in the event of an unrecoverable I/O exception.

isValueSupported

public boolean isValueSupported(float value)

mapValueToInteger

public int mapValueToInteger(float value)

Converts a floating-point value to its associated integer code based on the scale and offset parameters set for this instance.

Parameters:

value - a floating point value within the range of values supported by this instance

Returns:

if successful, an integer value

mapIntegerToValue

public float mapIntegerToValue(int integerCode)

Converts a coded integer to its associated floating-point value based on the scale and offset parameters set for this instance.

Parameters:

integerCode - a coded integer value within the range of values supported by this instance

Returns:

if successful, an integer value

toString

public String toString()

Overrides:

toString in class GvrsElement

getFillValueInt

public int getFillValueInt()

Gets the value that is assigned to all raster cells that have not been otherwise populated. Some data sources may treat this value as a "no-data" value while others may treat it as a meaningful default value. The fill value is specified when a GVRS file is first created and may not be modified afterwards.

The fill value is not required to be within the range specified by the minimum and maximum values.

Returns:

an arbitrary integer.

getMaxValueInt

public int getMaxValueInt()

Gets the maximum value specified for the range of this instance. The maximum value is specified when a GVRS file is first created and may not be modified afterwards.

Returns:

an arbitrary integer

getMinValueInt

public int getMinValueInt()

Gets the minimum value specified for the range of this instance. The minimum value is specified when a GVRS file is first created and may not be modified afterwards.

Returns:

an arbitrary integer

getMinValue

public float getMinValue()

Gets the minimum floating-point value specified for the range of this instance. The minimum value is specified when a GVRS file is first created and may not be modified afterwards.

The value returned from this method is computed from the minimum integer value, scale, and offset specified for this instance. Due to the limits of numerical precision, it may not be a perfect match for an integral value even in cases where that is expected.

Returns:

a computed floating-point value

getMaxValue

public float getMaxValue()

Gets the maximum floating-point value specified for the range of this instance. The maximum value is specified when a GVRS file is first created and may not be modified afterwards.

The value returned from this method is computed from the minimum integer value, scale, and offset specified for this instance. Due to the limits of numerical precision, it may not be a perfect match for an integral value even in cases where that is expected.

Returns:

a computed floating-point value

getFillValue

public float getFillValue()

Gets the value that is assigned to all raster cells that have not been otherwise populated. Some data sources may treat this value as a "no-data" value while others may treat it as a meaningful default value. The fill value is specified when a GVRS file is first created and may not be modified afterwards.

The fill value is not required to be within the range specified by the minimum and maximum values.

A fill value is allowed to be Float.NAN.

Returns:

an arbitrary floating-point value.