org.geotools.coverage.processing.operation

Class Interpolate

Object

AbstractOperation

Operation2D

Interpolate

All Implemented Interfaces:

Serializable, Operation

public class Interpolate
extends Operation2D

Specifies the interpolation type to be used to interpolate values for points which fall between grid cells. The default value is nearest neighbor. The new interpolation type operates on all sample dimensions. Possible values for type are: "NearestNeighbor", "Bilinear" and "Bicubic" (the "Optimal" interpolation type is currently not supported).

Geotools extension:
The Geotools implementation provides two extensions to OpenGIS specification: First, it accepts also an Interpolation argument type, for interoperability with Java Advanced Imaging. Second, it accepts also an array of String or Interpolation objects. When an array is specified, the first interpolation in the array is applied. If this interpolation returns a NaN value, then the second interpolation is tried as a fallback. If the second interpolation returns also a NaN value, then the third one is tried and so on until an interpolation returns a real number or until we reach the end of interpolation list. This behavior is convenient when processing remote sensing images of geophysics data, for example Sea Surface Temperature (SST), in which clouds may mask many pixels (i.e. set them to some NaN values). Because "Bicubic" interpolation needs 4×4 pixels while "Bilinear" interpolation needs only 2x2 pixels, the "Bilinear" interpolation is less likely to fails because of clouds (NaN values) than the "Bicubic" one (note: only one NaN value is enough to make an interpolation fails). One can workaround the problem by trying a bicubic interpolation first, then a linear interpolation if "Bicubic" failed at a particular location, etc. This behavior can be specified with the following "Type" argument: new String[]{"Bicubic", "Bilinear", "NearestNeighbor"}.

Name: "Interpolate"
JAI operator: N/A
Parameters:

Name	Class	Default value	Minimum value	Maximum value
"Source"	GridCoverage2D	N/A	N/A	N/A
"Type"	CharSequence	"NearestNeighbor"	N/A	N/A

Since:

2.2

Author:

Martin Desruisseaux (IRD)

See Also:

Operations.interpolate(org.opengis.coverage.grid.GridCoverage, java.lang.String), Interpolator2D, Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static ParameterDescriptor	TYPE The parameter descriptor for the interpolation type.

Fields inherited from class Operation2D

PRIMARY_SOURCE_INDEX, SOURCE_0

Fields inherited from class AbstractOperation

descriptor

Constructor Summary

Constructors

Constructor and Description
Interpolate() Constructs an "Interpolate" operation.

Method Summary

Modifier and Type	Method and Description
Coverage	doOperation(ParameterValueGroup parameters, Hints hints) Applies an interpolation to a grid coverage.

Methods inherited from class Operation2D

extractSources, getFactory

Methods inherited from class AbstractOperation

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

Methods inherited from class Object

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

Field Detail

TYPE

public static final ParameterDescriptor TYPE

The parameter descriptor for the interpolation type.

Constructor Detail

Interpolate

public Interpolate()

Constructs an "Interpolate" operation.

Method Detail

doOperation

public Coverage doOperation(ParameterValueGroup parameters,
                            Hints hints)

Applies an interpolation to a grid coverage. This method is invoked by org.geotools.coverage.processing.DefaultProcessor for the "Interpolate" operation.

Specified by:

doOperation in class AbstractOperation

Parameters:

parameters - List of name value pairs for the parameters required for the operation.

hints - A set of rendering hints, or null if none. The DefaultProcessor may provides hints for the following keys: Hints.COORDINATE_OPERATION_FACTORY and Hints.JAI_INSTANCE.

Returns:

The result as a coverage.