org.opengis.coverage

Interface Coverage

All Known Subinterfaces:

GridCoverage, GridCoverageResponse

All Known Implementing Classes:

AbstractCoverage, AbstractGridCoverage, DefaultGridCoverageResponse, GridCoverage2D, Interpolator2D

@UML(identifier="CV_Coverage",
     specification=ISO_19123)
public interface Coverage

A function from a spatial, temporal or spatiotemporal domain to an attribute range. A coverage associates a position within its domain to a record of values of defined data types. Examples include a raster image, polygon overlay, or digital elevation matrix. The essential property of coverage is to be able to generate a value for any point within its domain. How coverage is represented internally is not a concern.

For example consider the following different internal representations of coverage:

• A coverage may be represented by a set of polygons which exhaustively tile a plane (that is each point on the plane falls in precisely one polygon). The value returned by the coverage for a point is the value of an attribute of the polygon that contains the point.
• A coverage may be represented by a grid of values (a Discrete Grid Point Coverage). If the coverage is a Continuous Quadrilateral Grid Coverage using Nearest Neighbour interpolation method, then the value returned by the coverage for a point is that of the grid value whose location is nearest the point.
• Coverage may be represented by a mathematical function. The value returned by the coverage for a point is just the return value of the function when supplied the coordinates of the point as arguments.
• Coverage may be represented by combination of these. For example, coverage may be represented by a combination of mathematical functions valid over a set of polynomials.

Metadata

The legacy OGC 01-004 specification provided some methods for fetching metadata values attached to a coverage. The ISO 19123 specification do not provides such methods. Implementations that want to provide such metadata are encouraged to implement the PropertySource or WritablePropertySource interface.

Since:

GeoAPI 2.1

Author:

Stephane Fellah, Martin Desruisseaux (IRD), Wim Koolhoven, Alexander Petkov

Method Summary

Modifier and Type	Method and Description
Object	evaluate(DirectPosition point) Return the value vector for a given point in the coverage.
boolean[]	evaluate(DirectPosition point, boolean[] destination) Return a sequence of boolean values for a given point in the coverage.
byte[]	evaluate(DirectPosition point, byte[] destination) Return a sequence of unsigned byte values for a given point in the coverage.
Set<Record>	evaluate(DirectPosition p, Collection<String> list) Returns a set of records of feature attribute values for the specified direct position.
double[]	evaluate(DirectPosition point, double[] destination) Return a sequence of double values for a given point in the coverage.
float[]	evaluate(DirectPosition point, float[] destination) Return a sequence of float values for a given point in the coverage.
int[]	evaluate(DirectPosition point, int[] destination) Return a sequence of integer values for a given point in the coverage.
CoordinateReferenceSystem	getCoordinateReferenceSystem() Returns the coordinate reference system to which the objects in its domain are referenced.
Envelope	getEnvelope() The bounding box for the coverage domain in coordinate reference system coordinates.
int	getNumSampleDimensions() The number of sample dimensions in the coverage.
RecordType	getRangeType() Describes the range of the coverage.
RenderableImage	getRenderableImage(int xAxis, int yAxis) Returns 2D view of this coverage as a renderable image.
SampleDimension	getSampleDimension(int index) Retrieve sample dimension information for the coverage.
List<? extends Coverage>	getSources() Returns the sources data for a coverage.

Method Detail

getCoordinateReferenceSystem

@UML(identifier="CRS",
     obligation=MANDATORY,
     specification=ISO_19123)
CoordinateReferenceSystem getCoordinateReferenceSystem()

Returns the coordinate reference system to which the objects in its domain are referenced. This is the CRS used when accessing a coverage or grid coverage with the evaluate(...) methods. This coordinate reference system is usually different than coordinate system of the grid. It is the target coordinate reference system of the gridToCRS math transform.

Grid coverage can be accessed (re-projected) with new coordinate reference system with the GridCoverageProcessor component. In this case, a new instance of a grid coverage is created.

Returns:

The coordinate reference system used when accessing a coverage or grid coverage with the evaluate(...) methods.

getEnvelope

@UML(identifier="envelope",
     obligation=MANDATORY,
     specification=OGC_01004)
Envelope getEnvelope()

The bounding box for the coverage domain in coordinate reference system coordinates. For grid coverages, the grid cells are centered on each grid coordinate. The envelope for a 2-D grid coverage includes the following corner positions.

 (Minimum row - 0.5, Minimum column - 0.5) for the minimum coordinates
 (Maximum row - 0.5, Maximum column - 0.5) for the maximum coordinates
 

If a grid coverage does not have any associated coordinate reference system, the minimum and maximum coordinate points for the envelope will be empty sequences.

Returns:

The bounding box for the coverage domain in coordinate system coordinates.

getRangeType

@UML(identifier="rangeType",
     obligation=MANDATORY,
     specification=ISO_19123)
RecordType getRangeType()

Describes the range of the coverage. It consists of a list of attribute name/data type pairs. A simple list is the most common form of range type, but RecordType can be used recursively to describe more complex structures. The range type for a specific coverage shall be specified in an application schema.

Returns:

The coverage range.

evaluate

@UML(identifier="evaluate",
     obligation=MANDATORY,
     specification=ISO_19123)
Set<Record> evaluate(DirectPosition p,
                                                                                                          Collection<String> list)
                                                                                                   throws PointOutsideCoverageException,
                                                                                                          CannotEvaluateException

Returns a set of records of feature attribute values for the specified direct position. The parameter list is a sequence of feature attribute names each of which identifies a field of the range type. If list is null, the operation shall return a value for every field of the range type. Otherwise, it shall return a value for each field included in list. If the direct position passed is not in the domain of the coverage, then an exception is thrown. If the input direct position falls within two or more geometric objects within the domain, the operation shall return records of feature attribute values computed according to the common point rule.

NOTE: Normally, the operation will return a single record of feature attribute values.

Parameters:

p - The position where to evaluate.

list - The field of interest, or null for every fields.

Returns:

The feature attributes.

Throws:

PointOutsideCoverageException - if the point is outside the coverage domain.

CannotEvaluateException - If the point can't be evaluated for some other reason.

evaluate

@UML(identifier="evaluate",
     obligation=MANDATORY,
     specification=OGC_01004)
Object evaluate(DirectPosition point)
                                                                                              throws PointOutsideCoverageException,
                                                                                                     CannotEvaluateException

Return the value vector for a given point in the coverage. A value for each sample dimension is included in the vector. The default interpolation type used when accessing grid values for points which fall between grid cells is nearest neighbor.

The coordinate reference system of the point is the same as the grid coverage coordinate reference system (specified by the getCoordinateReferenceSystem() method).

WARNING: This method is inherited from the legacy OGC 01-004 specification and may be deprecated in a future version. We are for more experience and feedbacks on the value of this method.

Parameters:

point - Point at which to find the grid values.

Returns:

The value vector for a given point in the coverage.

Throws:

PointOutsideCoverageException - if the point is outside the coverage envelope.

CannotEvaluateException - If the point can't be evaluated for some other reason.

See Also:

Raster.getDataElements(int, int, Object)

evaluate

@UML(identifier="evaluateAsBoolean",
     obligation=MANDATORY,
     specification=OGC_01004)
boolean[] evaluate(DirectPosition point,
                                                                                                                 boolean[] destination)
                                                                                                          throws PointOutsideCoverageException,
                                                                                                                 CannotEvaluateException,
                                                                                                                 ArrayIndexOutOfBoundsException

Return a sequence of boolean values for a given point in the coverage. A value for each sample dimension is included in the sequence. The default interpolation type used when accessing grid values for points which fall between grid cells is nearest neighbor.

The coordinate reference system of the point is the same as the grid coverage coordinate reference system (specified by the getCoordinateReferenceSystem() method).

Parameters:

point - Point at which to find the coverage values.

destination - An optionally preallocated array in which to store the values, or null if none.

Returns:

A sequence of boolean values for a given point in the coverage. If destination was non-null, then it is returned. Otherwise, a new array is allocated and returned.

Throws:

PointOutsideCoverageException - if the point is outside the coverage envelope.

CannotEvaluateException - if the point can't be evaluated for some othe reason.

ArrayIndexOutOfBoundsException - if the destination array is not null and too small to hold the output.

evaluate

@UML(identifier="evaluateAsByte",
     obligation=MANDATORY,
     specification=OGC_01004)
byte[] evaluate(DirectPosition point,
                                                                                                           byte[] destination)
                                                                                                    throws PointOutsideCoverageException,
                                                                                                           CannotEvaluateException,
                                                                                                           ArrayIndexOutOfBoundsException

Return a sequence of unsigned byte values for a given point in the coverage. A value for each sample dimension is included in the sequence. The default interpolation type used when accessing grid values for points which fall between grid cells is nearest neighbor.

The coordinate reference system of the point is the same as the grid coverage coordinate reference system (specified by the getCoordinateReferenceSystem() method).

Parameters:

point - Point at which to find the coverage values.

destination - An optionally preallocated array in which to store the values, or null if none.

Returns:

A sequence of unsigned byte values for a given point in the coverage. If destination was non-null, then it is returned. Otherwise, a new array is allocated and returned.

Throws:

PointOutsideCoverageException - if the point is outside the coverage envelope.

CannotEvaluateException - if the point can't be evaluated for some othe reason.

ArrayIndexOutOfBoundsException - if the destination array is not null and too small to hold the output.

evaluate

@UML(identifier="evaluateAsInteger",
     obligation=MANDATORY,
     specification=OGC_01004)
int[] evaluate(DirectPosition point,
                                                                                                             int[] destination)
                                                                                                      throws PointOutsideCoverageException,
                                                                                                             CannotEvaluateException,
                                                                                                             ArrayIndexOutOfBoundsException

Return a sequence of integer values for a given point in the coverage. A value for each sample dimension is included in the sequence. The default interpolation type used when accessing grid values for points which fall between grid cells is nearest neighbor.

The coordinate reference system of the point is the same as the grid coverage coordinate reference system (specified by the getCoordinateReferenceSystem() method).

Parameters:

point - Point at which to find the grid values.

destination - An optionally preallocated array in which to store the values, or null if none.

Returns:

A sequence of integer values for a given point in the coverage. If destination was non-null, then it is returned. Otherwise, a new array is allocated and returned.

Throws:

PointOutsideCoverageException - if the point is outside the coverage envelope.

CannotEvaluateException - if the point can't be evaluated for some othe reason.

ArrayIndexOutOfBoundsException - if the destination array is not null and too small to hold the output.

See Also:

Raster.getPixel(int, int, int[])

evaluate

float[] evaluate(DirectPosition point,
                 float[] destination)
          throws PointOutsideCoverageException,
                 CannotEvaluateException,
                 ArrayIndexOutOfBoundsException

Return a sequence of float values for a given point in the coverage. A value for each sample dimension is included in the sequence. The default interpolation type used when accessing grid values for points which fall between grid cells is nearest neighbor.

The coordinate reference system of the point is the same as the grid coverage coordinate reference system (specified by the getCoordinateReferenceSystem() method).

Parameters:

point - Point at which to find the grid values.

destination - An optionally preallocated array in which to store the values, or null if none.

Returns:

A sequence of float values for a given point in the coverage. If destination was non-null, then it is returned. Otherwise, a new array is allocated and returned.

Throws:

PointOutsideCoverageException - if the point is outside the coverage envelope.

CannotEvaluateException - if the point can't be evaluated for some othe reason.

ArrayIndexOutOfBoundsException - if the destination array is not null and too small to hold the output.

See Also:

Raster.getPixel(int, int, float[])

evaluate

@UML(identifier="evaluateAsDouble",
     obligation=MANDATORY,
     specification=OGC_01004)
double[] evaluate(DirectPosition point,
                                                                                                               double[] destination)
                                                                                                        throws PointOutsideCoverageException,
                                                                                                               CannotEvaluateException,
                                                                                                               ArrayIndexOutOfBoundsException

Return a sequence of double values for a given point in the coverage. A value for each sample dimension is included in the sequence. The default interpolation type used when accessing grid values for points which fall between grid cells is nearest neighbor.

The coordinate reference system of the point is the same as the grid coverage coordinate reference system (specified by the getCoordinateReferenceSystem() method).

Parameters:

point - Point at which to find the grid values.

destination - An optionally preallocated array in which to store the values, or null if none.

Returns:

A sequence of double values for a given point in the coverage. If destination was non-null, then it is returned. Otherwise, a new array is allocated and returned.

Throws:

PointOutsideCoverageException - if the point is outside the coverage envelope.

CannotEvaluateException - If the point can't be evaluated for some othe reason.

ArrayIndexOutOfBoundsException - if the destination array is not null and too small to hold the output.

See Also:

Raster.getPixel(int, int, double[])

getNumSampleDimensions

@UML(identifier="numSampleDimensions",
     obligation=MANDATORY,
     specification=OGC_01004)
int getNumSampleDimensions()

The number of sample dimensions in the coverage. For grid coverages, a sample dimension is a band.

WARNING: This method is inherited from the legacy OGC 01-004 specification and may be deprecated in a future version. We are for more experience and feedbacks on the value of this method.

Returns:

The number of sample dimensions in the coverage.

getSampleDimension

@UML(identifier="getSampleDimension",
     obligation=MANDATORY,
     specification=OGC_01004)
SampleDimension getSampleDimension(int index)
                                                                                                                           throws IndexOutOfBoundsException

Retrieve sample dimension information for the coverage. For a grid coverage a sample dimension is a band. The sample dimension information include such things as description, data type of the value (bit, byte, integer...), the no data values, minimum and maximum values and a color table if one is associated with the dimension. A coverage must have at least one sample dimension.

WARNING: This method is inherited from the legacy OGC 01-004 specification and may be deprecated in a future version. We are for more experience and feedbacks on the value of this method.

Parameters:

index - Index for sample dimension to retrieve. Indices are numbered 0 to (n-1).

Returns:

Sample dimension information for the coverage.

Throws:

IndexOutOfBoundsException - if index is out of bounds.

getSources

@UML(identifier="getSource, numSource",
     obligation=MANDATORY,
     specification=OGC_01004)
List<? extends Coverage> getSources()

Returns the sources data for a coverage. This is intended to allow applications to establish what Coverages will be affected when others are updated, as well as to trace back to the "raw data".

This implementation specification does not include interfaces for creating collections of coverages therefore the list size will usually be one indicating an adapted grid coverage, or zero indicating a raw grid coverage.

WARNING: This method is inherited from the legacy OGC 01-004 specification and may be deprecated in a future version. We are for more experience and feedbacks on the value of this method.

Returns:

The list of sources data for a coverage.

getRenderableImage

@Extension
RenderableImage getRenderableImage(int xAxis,
                                              int yAxis)
                                       throws UnsupportedOperationException,
                                              IndexOutOfBoundsException

Returns 2D view of this coverage as a renderable image. This optional operation allows interoperability with Java2D. If this coverage is a GridCoverage backed by a RenderedImage, the underlying image can be obtained with: getRenderableImage(0,1).createDefaultRendering()

Parameters:

xAxis - Dimension to use for the x axis.

yAxis - Dimension to use for the y axis.

Returns:

A 2D view of this coverage as a renderable image.

Throws:

UnsupportedOperationException - if this optional operation is not supported.

IndexOutOfBoundsException - if xAxis or yAxis is out of bounds.