org.esa.snap.core.datamodel

Class VirtualBand

java.lang.Object

com.bc.ceres.core.ExtensibleObject

org.esa.snap.core.datamodel.ProductNode

org.esa.snap.core.datamodel.DataNode

org.esa.snap.core.datamodel.RasterDataNode

org.esa.snap.core.datamodel.AbstractBand

org.esa.snap.core.datamodel.Band

org.esa.snap.core.datamodel.VirtualBand

All Implemented Interfaces:

Extensible, Scaling, SceneTransformProvider

public class VirtualBand
extends Band

A band contains the data for geophysical parameter in remote sensing data products. Bands are two-dimensional images which hold their pixel values (samples) in a buffer of the type ProductData. The band class is just a container for attached metadata of the band, currently:

• the flag coding FlagCoding
• the band index at which position the band is stored in the associated product
• the center wavelength of the band
• the bandwidth of the band
• the solar spectral flux of the band
• the width and height of the band

The band can contain a buffer to the real data, but this buffer must be read explicitely, to keep the memory fingerprint small, the data is not read automatically.

The several getPixel and readPixel methods of this class do not necessarily return the values contained in the data buffer of type ProductData. If the scalingFactor, scalingOffset or log10Scaled are set a conversion of the form scalingFactor * rawSample + scalingOffset is applied to the raw samples before the getPixel and readPixel methods return the actual pixel values. If the log10Scaled property is true then the conversion is pow(10, scalingFactor * rawSample + scalingOffset). The several setPixel and writePixel perform the inverse operations in this case.

Version:

$Revision$ $Date$

See Also:

ProductData

Nested Class Summary

Nested classes/interfaces inherited from class org.esa.snap.core.datamodel.RasterDataNode

RasterDataNode.RasterDataProcessor

Field Summary

Fields

Modifier and Type	Field and Description
static String	PROPERTY_NAME_EXPRESSION

Fields inherited from class org.esa.snap.core.datamodel.Band

PROPERTY_NAME_SAMPLE_CODING, PROPERTY_NAME_SOLAR_FLUX, PROPERTY_NAME_SPECTRAL_BAND_INDEX, PROPERTY_NAME_SPECTRAL_BANDWIDTH, PROPERTY_NAME_SPECTRAL_WAVELENGTH

Fields inherited from class org.esa.snap.core.datamodel.RasterDataNode

INVALID_POS_TEXT, IO_ERROR_TEXT, NO_DATA_TEXT, PROPERTY_NAME_ANCILLARY_RELATIONS, PROPERTY_NAME_ANCILLARY_VARIABLES, PROPERTY_NAME_GEO_CODING, PROPERTY_NAME_IMAGE_INFO, PROPERTY_NAME_IMAGE_TO_MODEL_TRANSFORM, PROPERTY_NAME_LOG_10_SCALED, PROPERTY_NAME_MODEL_TO_SCENE_TRANSFORM, PROPERTY_NAME_NO_DATA_VALUE, PROPERTY_NAME_NO_DATA_VALUE_USED, PROPERTY_NAME_SCALING_FACTOR, PROPERTY_NAME_SCALING_OFFSET, PROPERTY_NAME_SCENE_TO_MODEL_TRANSFORM, PROPERTY_NAME_STX, PROPERTY_NAME_TIME_CODING, PROPERTY_NAME_VALID_PIXEL_EXPRESSION

Fields inherited from class org.esa.snap.core.datamodel.DataNode

PROPERTY_NAME_DATA, PROPERTY_NAME_READ_ONLY, PROPERTY_NAME_SYNTHETIC, PROPERTY_NAME_UNIT

Fields inherited from class org.esa.snap.core.datamodel.ProductNode

PROPERTY_NAME_DESCRIPTION, PROPERTY_NAME_NAME

Fields inherited from interface org.esa.snap.core.datamodel.Scaling

IDENTITY

Constructor Summary

Constructors

Constructor and Description
VirtualBand(String name, int dataType, int width, int height, String expression) Constructs a new Band.

Method Summary

Modifier and Type	Method and Description
void	acceptVisitor(ProductVisitor visitor) Accepts the given visitor.
protected RenderedImage	createSourceImage() Creates the source image associated with this RasterDataNode.
static MultiLevelImage	createSourceImage(RasterDataNode raster, String expression) Create a MultiLevelImage that computes its pixel values from the given band math expression.
void	dispose() Releases all of the resources used by this object instance and all of its owned children.
String	getExpression()
long	getRawStorageSize(ProductSubsetDef subsetDef) Gets an estimated raw storage size in bytes of this product node.
void	setExpression(String expression)
void	setPixelDouble(int x, int y, double pixelValue) Sets the pixel value at the given pixel coordinate to the given pixel value.
void	setPixelFloat(int x, int y, float pixelValue) Sets the pixel at the given pixel coordinate to the given pixel value.
void	setPixelInt(int x, int y, int pixelValue) Sets the pixel at the given pixel co-ordinate to the given pixel value.
String	toString() Creates a string defining this band object.
void	updateExpression(String oldExternalName, String newExternalName) Asks a product node to replace all occurences of and references to the node name given by oldExternalName with oldExternalName.
void	writePixels(int x, int y, int w, int h, double[] pixels, ProgressMonitor pm) Retrieves the range of pixels specified by the coordinates as double array.
void	writePixels(int x, int y, int w, int h, float[] pixels, ProgressMonitor pm) Retrieves the range of pixels specified by the coordinates as float array.
void	writePixels(int x, int y, int w, int h, int[] pixels, ProgressMonitor pm) Retrieves the range of pixels specified by the coordinates as integer array.

Methods inherited from class org.esa.snap.core.datamodel.Band

computeStxImpl, createDefaultImageInfo, getFlagCoding, getIndexCoding, getSampleCoding, getSolarFlux, getSpectralBandIndex, getSpectralBandwidth, getSpectralWavelength, isFlagBand, isIndexBand, readRasterData, readRasterDataFully, removeFromFile, setSampleCoding, setSolarFlux, setSpectralBandIndex, setSpectralBandwidth, setSpectralWavelength, writeRasterData, writeRasterDataFully

Methods inherited from class org.esa.snap.core.datamodel.AbstractBand

ensureMinLengthArray, ensureMinLengthArray, ensureMinLengthArray, ensureRasterData, getPixelDouble, getPixelFloat, getPixelInt, getPixels, getPixels, getPixels, getRasterHeight, getRasterWidth, loadRasterData, readPixels, readPixels, readPixels, setPixels, setPixels, setPixels, unloadRasterData

Methods inherited from class org.esa.snap.core.datamodel.RasterDataNode

addAncillaryVariable, canBeOrthorectified, checkCompatibleRasterData, clearNoDataValue, createColorIndexedImage, createCompatibleRasterData, createCompatibleRasterData, createCompatibleSceneRasterData, createDefaultImageInfo, createMultiLevelModel, createPointing, createRgbImage, createTransectProfileData, fireImageInfoChanged, getAncillaryRelations, getAncillaryVariable, getAncillaryVariables, getGeoCoding, getGeophysicalDataType, getGeophysicalImage, getGeophysicalNoDataValue, getImageInfo, getImageInfo, getImageInfo, getImageToModelTransform, getModelToSceneTransform, getMultiLevelModel, getNoDataValue, getOverlayMaskGroup, getPixels, getPixels, getPixels, getPixelString, getPointing, getRasterData, getRasterSize, getSampleFloat, getSampleInt, getScalingFactor, getScalingOffset, getSceneToModelTransform, getSourceImage, getStx, getStx, getTimeCoding, getValidMaskExpression, getValidMaskImage, getValidPixelExpression, getValidShape, hasIntPixels, hasRasterData, isCompatibleRasterData, isFloatingPointType, isGeophysicalImageSet, isLog10Scaled, isNoDataValueSet, isNoDataValueUsed, isPixelValid, isPixelValid, isPixelValid, isScalingApplied, isSourceImageSet, isStxSet, isValidMaskImageSet, isValidMaskProperty, isValidMaskUsed, loadRasterData, processRasterData, quantizeRasterData, quantizeRasterData, readPixels, readPixels, readPixels, readRasterData, readRasterDataFully, readValidMask, removeAncillaryVariable, resetValidMask, scale, scaleInverse, setAncillaryRelations, setGeoCoding, setGeophysicalNoDataValue, setImageInfo, setImageInfo, setImageToModelTransform, setLog10Scaled, setModelToSceneTransform, setModified, setNoDataValue, setNoDataValueUsed, setRasterData, setScalingFactor, setScalingOffset, setSceneToModelTransform, setSourceImage, setSourceImage, setStx, setTimeCoding, setValidPixelExpression, writePixels, writePixels, writePixels, writeRasterData, writeRasterDataFully

Methods inherited from class org.esa.snap.core.datamodel.DataNode

checkDataCompatibility, createCompatibleProductData, fireProductNodeDataChanged, getData, getDataElems, getDataElemSize, getDataType, getNumDataElems, getUnit, isReadOnly, isSynthetic, setData, setDataElems, setReadOnly, setSynthetic, setUnit

Methods inherited from class org.esa.snap.core.datamodel.ProductNode

fireProductNodeChanged, fireProductNodeChanged, getDescription, getDisplayName, getName, getOwner, getProduct, getProductReader, getProductReaderSafe, getProductRefString, getProductSafe, getProductWriter, getProductWriterSafe, getRawStorageSize, isModified, isPartOfSubset, isValidNodeName, setDescription, setName, setOwner

Methods inherited from class com.bc.ceres.core.ExtensibleObject

getExtension

Methods inherited from class java.lang.Object

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

Field Detail

PROPERTY_NAME_EXPRESSION

public static final String PROPERTY_NAME_EXPRESSION

See Also:

Constant Field Values

Constructor Detail

VirtualBand

public VirtualBand(String name,
                   int dataType,
                   int width,
                   int height,
                   String expression)

Constructs a new Band.

Parameters:

name - the name of the new object

dataType - the raster data type, must be one of the multiple ProductData.TYPE_X constants, with the exception of ProductData.TYPE_UINT32

width - the width of the raster in pixels

height - the height of the raster in pixels

expression - the expression code

Method Detail

getExpression

public String getExpression()

setExpression

public void setExpression(String expression)

updateExpression

public void updateExpression(String oldExternalName,
                             String newExternalName)

Asks a product node to replace all occurences of and references to the node name given by oldExternalName with oldExternalName. Such references most often occur in band arithmetic expressions.

Overrides:

updateExpression in class RasterDataNode

Parameters:

oldExternalName - The old node name.

newExternalName - The new node name.

setPixelInt

public void setPixelInt(int x,
                        int y,
                        int pixelValue)

Description copied from class: AbstractBand

Sets the pixel at the given pixel co-ordinate to the given pixel value.

Overrides:

setPixelInt in class AbstractBand

Parameters:

x - The X co-ordinate of the pixel location

y - The Y co-ordinate of the pixel location

pixelValue - the new pixel value

setPixelFloat

public void setPixelFloat(int x,
                          int y,
                          float pixelValue)

Description copied from class: AbstractBand

Sets the pixel at the given pixel coordinate to the given pixel value.

Overrides:

setPixelFloat in class AbstractBand

Parameters:

x - The X co-ordinate of the pixel location

y - The Y co-ordinate of the pixel location

pixelValue - the new pixel value

setPixelDouble

public void setPixelDouble(int x,
                           int y,
                           double pixelValue)

Description copied from class: AbstractBand

Sets the pixel value at the given pixel coordinate to the given pixel value.

Overrides:

setPixelDouble in class AbstractBand

Parameters:

x - The X co-ordinate of the pixel location

y - The Y co-ordinate of the pixel location

pixelValue - the new pixel value

writePixels

public void writePixels(int x,
                        int y,
                        int w,
                        int h,
                        int[] pixels,
                        ProgressMonitor pm)
                 throws IOException

Retrieves the range of pixels specified by the coordinates as integer array. Reads the data from disk if ot is not in memory yet. If the data is loaded, just copies the data..

Overrides:

writePixels in class AbstractBand

Parameters:

x - x offset into the band

y - y offset into the band

w - width of the pixel array to be read

h - height of the pixel array to be read.

pixels - integer array to be filled with data

pm - a monitor to inform the user about progress

Throws:

IOException - if an I/O error occurs

writePixels

public void writePixels(int x,
                        int y,
                        int w,
                        int h,
                        float[] pixels,
                        ProgressMonitor pm)
                 throws IOException

Retrieves the range of pixels specified by the coordinates as float array. Reads the data from disk if ot is not in memory yet. If the data is loaded, just copies the data..

Overrides:

writePixels in class AbstractBand

Parameters:

x - x offset into the band

y - y offset into the band

w - width of the pixel array to be read

h - height of the pixel array to be read.

pixels - float array to be filled with data

pm - a monitor to inform the user about progress

Throws:

IOException - if an I/O error occurs

writePixels

public void writePixels(int x,
                        int y,
                        int w,
                        int h,
                        double[] pixels,
                        ProgressMonitor pm)
                 throws IOException

Retrieves the range of pixels specified by the coordinates as double array. Reads the data from disk if ot is not in memory yet. If the data is loaded, just copies the data..

Overrides:

writePixels in class AbstractBand

Parameters:

x - x offset into the band

y - y offset into the band

w - width of the pixel array to be read

h - height of the pixel array to be read.

pixels - double array to be filled with data

pm - a monitor to inform the user about progress

Throws:

IOException - if an I/O error occurs

acceptVisitor

public void acceptVisitor(ProductVisitor visitor)

Accepts the given visitor. This method implements the well known 'Visitor' design pattern of the gang-of-four. The visitor pattern allows to define new operations on the product data model without the need to add more code to it. The new operation is implemented by the visitor.

The method simply calls visitor.visit(this).

Overrides:

acceptVisitor in class Band

Parameters:

visitor - the visitor, must not be null

getRawStorageSize

public long getRawStorageSize(ProductSubsetDef subsetDef)

Gets an estimated raw storage size in bytes of this product node.

Overrides:

getRawStorageSize in class Band

Parameters:

subsetDef - if not null the subset may limit the size returned

Returns:

the size in bytes.

toString

public String toString()

Creates a string defining this band object.

Overrides:

toString in class Band

dispose

public void dispose()

Releases all of the resources used by this object instance and all of its owned children. Its primary use is to allow the garbage collector to perform a vanilla job.

This method should be called only if it is for sure that this object instance will never be used again. The results of referencing an instance of this class after a call to dispose() are undefined.

Overrides of this method should always call super.dispose(); after disposing this instance.

Overrides:

dispose in class Band

createSourceImage

protected RenderedImage createSourceImage()

Description copied from class: RasterDataNode

Creates the source image associated with this RasterDataNode. This shall preferably be a MultiLevelImage instance which recognises this raster data node's imageToModelTransform property, if set.

Overrides:

createSourceImage in class Band

Returns:

A new source image instance.

createSourceImage

public static MultiLevelImage createSourceImage(RasterDataNode raster,
                                                String expression)

Create a MultiLevelImage that computes its pixel values from the given band math expression. The returned image is intended to be used as source image for the given target raster.

Non-API.

Parameters:

raster - The raster data node.

expression - The band-arithmetic expression.

Returns:

A multi-level image.