Package org.geotools.api.coverage

Class InterpolationMethod

Object

CodeList<InterpolationMethod>

InterpolationMethod

All Implemented Interfaces:

Serializable, Comparable<InterpolationMethod>

@UML(identifier="CV_InterpolationMethod",
     specification=ISO_19123)
public class InterpolationMethod
extends CodeList<InterpolationMethod>

A list of codes that identify interpolation methods that may be used for evaluating continuous coverages. Evaluation of a continuous coverage involves interpolation between known feature attribute values associated with geometric objects in the domain of the discrete coverage that is provided as control for the continuous coverage. This code list includes 9 interpolation methods. Each is used in the context of specified geometric configurations (table below). Since InterpolationMethod is a CodeList, it may be extended in an application schema that specifies additional interpolation methods.

Method	Coverage Type	Value object dimension
Nearest Neighbour	Any	Any
Linear	Segmented Curve	1
Quadratic	Segmented Curve	1
Cubic	Segmented Curve	1
Bilinear	Quadrilateral Grid	2
Biquadratic	Quadrilateral Grid	2
Bicubic	Quadrilateral Grid	2
Lost Area	Thiessen Polygon, Hexagonal Grid	2
Barycentric	TIN	2

Since:

GeoAPI 2.1

Author:

Martin Desruisseaux (IRD)

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final InterpolationMethod	BARYCENTRIC	Barycentric interpolation.
static final InterpolationMethod	BICUBIC	Interpolation based on the assumption that feature attribute values vary as a bicubic function of position within the grid cell.
static final InterpolationMethod	BILINEAR	Interpolation based on the assumption that feature attribute values vary as a bilinear function of position within the grid cell.
static final InterpolationMethod	BIQUADRATIC	Interpolation based on the assumption that feature attribute values vary as a biquadratic function of position within the grid cell.
static final InterpolationMethod	CUBIC	Interpolation based on the assumption that feature attribute values vary as a cubic function of distance along a value segment.
static final InterpolationMethod	LINEAR	Interpolation based on the assumption that feature attribute values vary in proportion to distance along a value segment.
static final InterpolationMethod	LOST_AREA	Lost area interpolation.
static final InterpolationMethod	NEAREST_NEIGHBOUR	Generates a feature attribute value at a direct position by assigning it the feature attribute value associated with the nearest domain object in the domain of the coverage.
static final InterpolationMethod	QUADRATIC	Interpolation based on the assumption that feature attribute values vary as a quadratic function of distance along a value segment.

Method Summary

Modifier and Type	Method	Description
InterpolationMethod[]	family()	Returns the list of enumerations of the same kind than this enum.
static InterpolationMethod	valueOf(String code)	Returns the interpolation method that matches the given string, or returns a new one if none match it.
static InterpolationMethod[]	values()	Returns the list of InterpolationMethods.

Methods inherited from class CodeList

compareTo, equals, hashCode, identifier, matches, name, ordinal, readResolve, toString, valueOf

Methods inherited from class Object

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

Field Details

NEAREST_NEIGHBOUR

@UML(identifier="Nearest neighbour",
     obligation=CONDITIONAL,
     specification=ISO_19123)
public static final InterpolationMethod NEAREST_NEIGHBOUR

Generates a feature attribute value at a direct position by assigning it the feature attribute value associated with the nearest domain object in the domain of the coverage. Nearest neighbour interpolation extends a discrete coverage to a step function defined on the convex hull of the domain objects in the domain of the coverage. Nearest neighbour interpolation is the only interpolation method described in ISO 19123 that can be used to interpolate attributes that have nominal or ordinal values.

NOTE: In the case of a discrete point coverage, the "steps" of the step function are the Thiessen polygons generated by the set of points in the domain of the coverage.

LINEAR

@UML(identifier="Linear interpolation",
     obligation=CONDITIONAL,
     specification=ISO_19123)
public static final InterpolationMethod LINEAR

Interpolation based on the assumption that feature attribute values vary in proportion to distance along a value segment.

v = a + bx

Linear interpolation may be used to interpolate feature attribute values along a line segment connecting any two point value pairs. It may also be used to interpolate feature attribute values at positions along a curve of any form, if the positions are described by values of an arc-length parameter.

Given two point value pairs (p_s, v_s) and (p_t, v_t), where p_s is the start point and p_t is the end point of a value segment, and v_s and v_t are the feature attribute values associated with those points, the feature attribute value v_i associated with the direct position p_i is:

v_i = v_s + (v_t - v_s) ((p_i - p_s)/(p_t - p_s))

QUADRATIC

@UML(identifier="Quadratic interpolation",
     obligation=CONDITIONAL,
     specification=ISO_19123)
public static final InterpolationMethod QUADRATIC

Interpolation based on the assumption that feature attribute values vary as a quadratic function of distance along a value segment.

v = a + bx + cx²

where a is the value of a feature attribute at the start of a value segment and v is the value of a feature attribute at distance x along the curve from the start. Three point value pairs are needed to provide control values for calculating the coefficients of the function.

CUBIC

@UML(identifier="Cubic interpolation",
     obligation=CONDITIONAL,
     specification=ISO_19123)
public static final InterpolationMethod CUBIC

Interpolation based on the assumption that feature attribute values vary as a cubic function of distance along a value segment.

v = a + bx + cx² + dx³

where a is the value of a feature attribute at the start of a value segment and v is the value of a feature attribute at distance x along the curve from the start. Four point value pairs are needed to provide control values for calculating the coefficients of the function.

BILINEAR

@UML(identifier="Bilinear interpolation",
     obligation=CONDITIONAL,
     specification=ISO_19123)
public static final InterpolationMethod BILINEAR

Interpolation based on the assumption that feature attribute values vary as a bilinear function of position within the grid cell.

BIQUADRATIC

@UML(identifier="Biquadratic interpolation",
     obligation=CONDITIONAL,
     specification=ISO_19123)
public static final InterpolationMethod BIQUADRATIC

Interpolation based on the assumption that feature attribute values vary as a biquadratic function of position within the grid cell.

BICUBIC

@UML(identifier="Bicubic interpolation",
     obligation=CONDITIONAL,
     specification=ISO_19123)
public static final InterpolationMethod BICUBIC

Interpolation based on the assumption that feature attribute values vary as a bicubic function of position within the grid cell.

LOST_AREA

@UML(identifier="Lost area interpolation",
     obligation=CONDITIONAL,
     specification=ISO_19123)
public static final InterpolationMethod LOST_AREA

Lost area interpolation.

BARYCENTRIC

@UML(identifier="Barycentric interpolation",
     obligation=CONDITIONAL,
     specification=ISO_19123)
public static final InterpolationMethod BARYCENTRIC

Barycentric interpolation.

Method Details

values

public static InterpolationMethod[] values()

Returns the list of InterpolationMethods.

Returns:

The list of codes declared in the current JVM.

family

public InterpolationMethod[] family()

Returns the list of enumerations of the same kind than this enum.

Specified by:

family in class CodeList<InterpolationMethod>

Returns:

The codes of the same kind than this code.

valueOf

public static InterpolationMethod valueOf(String code)

Returns the interpolation method that matches the given string, or returns a new one if none match it.

Parameters:

code - The name of the code to fetch or to create.

Returns:

A code matching the given name.