org.geotools.coverage.processing.operation
Class Histogram

Object
  AbstractOperation
      Operation2D
          OperationJAI
              AbstractStatisticsOperationJAI
                  Histogram

All Implemented Interfaces:

Serializable, Operation

public class Histogram
extends AbstractStatisticsOperationJAI

* 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 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

static String

GT_SYNTHETIC_PROPERTY_HISTOGRAM String key for getting the Histogram object.

Fields inherited from class AbstractStatisticsOperationJAI

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

Histogram()
Default constructor for the Histogram operation.

Method Summary

protected boolean	computeOnGeophysicsValues(ParameterValueGroup parameters) This operation MUST be performed on the geophysics data for this GridCoverage2D.
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 ParameterBlockJAI	prepareParameters(ParameterValueGroup parameters) Copies parameter values from the specified ParameterValueGroup to the ParameterBlockJAI

Methods inherited from class OperationJAI

createRenderedImage, deriveCategory, deriveGridCoverage, deriveName, deriveRange, deriveSampleDimension, deriveUnit, doOperation, equals, getJAI, getOperationDescriptor, getQuantitative, resampleToCommonGeometry

Methods inherited from class Operation2D

extractSources, getFactory

Methods inherited from class AbstractOperation

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

Methods inherited from class Object

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

Field Detail

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 Detail

Histogram

public Histogram()
          throws OperationNotFoundException

Default constructor for the Histogram operation.

Throws:

OperationNotFoundException

Method Detail

computeOnGeophysicsValues

protected boolean computeOnGeophysicsValues(ParameterValueGroup parameters)

This operation MUST be performed on the geophysics data for this GridCoverage2D.

Overrides:

computeOnGeophysicsValues in class Operation2D

Parameters:

parameters - ParameterValueGroup that describes this operation

Returns:

always true.

See Also:

GridCoverage2D.geophysics(boolean)

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.

See Also:

OperationJAI#getProperties(RenderedImage, CoordinateReferenceSystem, InternationalString, MathTransform, GridCoverage2D[], org.geotools.coverage.processing.OperationJAI.Parameters),

prepareParameters

protected ParameterBlockJAI prepareParameters(ParameterValueGroup parameters)

Description copied from class: AbstractStatisticsOperationJAI

Copies parameter values from the specified ParameterValueGroup to the ParameterBlockJAI

Overrides:

prepareParameters in class AbstractStatisticsOperationJAI

Parameters:

parameters - The ParameterValueGroup to be copied.

Returns:

A copy of the provided ParameterValueGroup as a JAI block.

See Also:

OperationJAI.prepareParameters(org.opengis.parameter.ParameterValueGroup)