Package org.geotools.coverage.processing.operation

Class Histogram

Object

AbstractOperation

Operation2D

OperationJAI

BaseStatisticsOperationJAI

Histogram

All Implemented Interfaces:

Serializable, Operation

public class Histogram
extends BaseStatisticsOperationJAI

* This operation simply wraps JAI Histogram operations described by HistogramDescriptor inside a GeoTools operation in order to make it spatial-aware.

For the moment this is a very simple wrap. Plans on the 2.4 and successive versions of this operation are to add the ability to use spatial ROIs and to specific Spatial subsampling. As of now, ROI has to be a Java2D Shape subclass and the parameters to control x and y subsamplings got to be Integer, which means pixel-aware.

For more information on how the underlying JAI operators works you can have a look here: HistogramDescriptor <a href="http://download.java.net/media/jai/javadoc/1.1.3/jai-apidocs/javax/media/jai/Histogram.html>Histogram

How to use this operation Here is a very simple example on how to use this operation in order to get the Histogram of the source coverage. final OperationJAI op=new OperationJAI("Histogram"); ParameterValueGroup params = op.getParameters(); params.parameter("Source").setValue(coverage); coverage=(GridCoverage2D) op.doOperation(params,null); System.out.println(((double[])coverage.getProperty("histogram")));

Since:

2.4

Author:

Simone Giannecchini

See Also:

• Histogram
• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class OperationJAI

OperationJAI.Parameters

Field Summary

Fields

Modifier and Type	Field	Description
static final String	GT_SYNTHETIC_PROPERTY_HISTOGRAM	String key for getting the Histogram object.

Fields inherited from class BaseStatisticsOperationJAI

LOGGER, ROI, SPATIAL_SUBSAMPLING_X, SPATIAL_SUBSAMPLING_Y

Fields inherited from class OperationJAI

operation, RENDERED_MODE

Fields inherited from class Operation2D

PRIMARY_SOURCE_INDEX, SOURCE_0

Fields inherited from class AbstractOperation

descriptor

Constructor Summary

Constructors

Constructor	Description
Histogram()	Default constructor for the Histogram operation.

Method Summary

Modifier and Type	Method	Description
String	getName()	Returns the name of the processing operation.
protected Map<String,?>	getProperties(RenderedImage data, CoordinateReferenceSystem crs, InternationalString name, MathTransform toCRS, GridCoverage2D[] sources, OperationJAI.Parameters parameters)	Prepare the Histogram property for this histogram operation.
protected void	handleJAIEXTParams(ParameterBlockJAI parameters, ParameterValueGroup parameters2)	Extension point for adding to the JAI ParameterBlockJAI object the parameters defined in the ParameterValueGroup, which can be read by the JAI-EXT operations.
protected ParameterBlockJAI	prepareParameters(ParameterValueGroup parameters)	Copies parameter values from the specified ParameterValueGroup to the ParameterBlockJAI

Methods inherited from class BaseStatisticsOperationJAI

convertPolygon

Methods inherited from class OperationJAI

createRenderedImage, deriveCategory, deriveGridCoverage, deriveName, deriveRange, deriveSampleDimension, deriveUnit, doOperation, equals, extractSources, getJAI, getOperationDescriptor, getQuantitative, handleROINoDataInternal, handleROINoDataProperties, hashCode, resampleToCommonGeometry

Methods inherited from class Operation2D

extractSources, getFactory

Methods inherited from class AbstractOperation

getDescription, getDocURL, getNumSources, getParameters, getVendor, getVersion, toString

Methods inherited from class Object

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

Field Details

GT_SYNTHETIC_PROPERTY_HISTOGRAM

public static final String GT_SYNTHETIC_PROPERTY_HISTOGRAM

String key for getting the Histogram object.

See Also:

• Constant Field Values

Constructor Details

Histogram

public Histogram()
          throws OperationNotFoundException

Default constructor for the Histogram operation.

Throws:

OperationNotFoundException

Method Details

getName

public String getName()

Description copied from class: AbstractOperation

Returns the name of the processing operation. The default implementation returns the AbstractOperation.descriptor code name.

Specified by:

getName in interface Operation

Overrides:

getName in class AbstractOperation

Returns:

The name of the processing operation.

getProperties

protected Map<String,?> getProperties(RenderedImage data,
 CoordinateReferenceSystem crs,
 InternationalString name,
 MathTransform toCRS,
 GridCoverage2D[] sources,
 OperationJAI.Parameters parameters)

Prepare the Histogram property for this histogram operation.

See HistogramDescriptor for more info.

Overrides:

getProperties in class OperationJAI

Parameters:

data - The RenderedImage created by this operation.

crs - The coordinate reference system assigned to the coverage this OperationJAI will produce.

name - The name assigned to the coverage this OperationJAI will produce.

toCRS - The transform from grid to crs to be assigned to the coverage this OperationJAI will produce.

sources - The sources to be assigned to the coverage this OperationJAI will produce.

parameters - The parameters that were used by this OperationJAI.

Returns:

a Map with the properties generated by this OperationJAI or null if we haven't any.

prepareParameters

protected ParameterBlockJAI prepareParameters(ParameterValueGroup parameters)

Description copied from class: BaseStatisticsOperationJAI

Copies parameter values from the specified ParameterValueGroup to the ParameterBlockJAI

Overrides:

prepareParameters in class BaseStatisticsOperationJAI

Parameters:

parameters - The ParameterValueGroup to be copied.

Returns:

A copy of the provided ParameterValueGroup as a JAI block.

See Also:

• OperationJAI.prepareParameters(org.geotools.api.parameter.ParameterValueGroup)

handleJAIEXTParams

protected void handleJAIEXTParams(ParameterBlockJAI parameters,
 ParameterValueGroup parameters2)

Description copied from class: OperationJAI

Extension point for adding to the JAI ParameterBlockJAI object the parameters defined in the ParameterValueGroup, which can be read by the JAI-EXT operations.

Notice that if you are using JAI, the new parameters will not be accepted by the ParameterBlockJAI instance.

Overrides:

handleJAIEXTParams in class OperationJAI

Parameters:

parameters - ParameterBlockJAI instance used by the current JAI-EXT/JAI operation

parameters2 - ParameterValueGroup instance containing input operation parameters