org.geotools.coverage

Class AbstractCoverage

Object

PropertySourceImpl

AbstractCoverage

All Implemented Interfaces:

Serializable, PropertySource, Coverage

Direct Known Subclasses:

AbstractGridCoverage

public abstract class AbstractCoverage
extends PropertySourceImpl
implements Coverage

Base class of all coverage type. 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. 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.

Since:

2.1

Author:

Martin Desruisseaux (IRD)

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	AbstractCoverage.Renderable A view of a coverage as a renderable image.

Field Summary

Fields

Modifier and Type	Field and Description
protected CoordinateReferenceSystem	crs The coordinate reference system, or null if there is none.

Fields inherited from class PropertySourceImpl

cachedPropertyNames, properties, propertySources

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractCoverage(CharSequence name, CoordinateReferenceSystem crs, PropertySource propertySource, Map<?,?> properties) Constructs a coverage using the specified coordinate reference system.
protected	AbstractCoverage(CharSequence name, Coverage coverage) Constructs a new coverage with the same parameters than the specified coverage.

Method Summary

Modifier and Type	Method and Description
boolean	dispose(boolean force) Provides a hint that a coverage will no longer be accessed from a reference in user space.
boolean[]	evaluate(DirectPosition coord, boolean[] dest) Returns a sequence of boolean values for a given point in the coverage.
byte[]	evaluate(DirectPosition coord, byte[] dest) Returns a sequence of 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 coord, double[] dest) Returns a sequence of double values for a given point in the coverage.
float[]	evaluate(DirectPosition coord, float[] dest) Returns a sequence of float values for a given point in the coverage.
int[]	evaluate(DirectPosition coord, int[] dest) Returns 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.
int	getDimension() Returns the dimension of this coverage.
Envelope	getEnvelope() Returns the bounding box for the coverage domain in coordinate reference system coordinates.
Locale	getLocale() Returns the default locale for logging, error messages, etc.
InternationalString	getName() Returns the coverage name, or null if none.
RecordType	getRangeType() Describes the range of the coverage.
RenderableImage	getRenderableImage(int xAxis, int yAxis) Returns 2D view of this grid coverage as a renderable image.
List<? extends Coverage>	getSources() Returns the source data for a coverage.
void	show() Displays this coverage in a windows.
void	show(String title) Display this coverage in a windows.
void	show(String title, int xAxis, int yAxis) Display this coverage in a windows.
String	toString() Returns a string representation of this coverage.

Methods inherited from class PropertySourceImpl

getProperties, getProperty, getPropertyClass, getPropertyNames, getPropertyNames

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface Coverage

evaluate, getNumSampleDimensions, getSampleDimension

Field Detail

crs

protected final CoordinateReferenceSystem crs

The coordinate reference system, or null if there is none.

Constructor Detail

AbstractCoverage

protected AbstractCoverage(CharSequence name,
                           CoordinateReferenceSystem crs,
                           PropertySource propertySource,
                           Map<?,?> properties)

Constructs a coverage using the specified coordinate reference system. If the coordinate reference system is null, then the subclasses must override getDimension().

Parameters:

name - The coverage name, or null if none.

crs - The coordinate reference system. This specifies the CRS used when accessing a coverage or grid coverage with the evaluate(...) methods.

propertySource - The source for this coverage, or null if none. Source may be (but is not limited to) a PlanarImage or an other AbstractCoverage object.

properties - The set of properties for this coverage, or null if there is none. Keys are String objects (CaselessStringKey are accepted as well), while values may be any Object.

AbstractCoverage

protected AbstractCoverage(CharSequence name,
                           Coverage coverage)

Constructs a new coverage with the same parameters than the specified coverage.

Note: This constructor keeps a strong reference to the source coverage (through PropertySourceImpl).

Parameters:

name - The name for this coverage, or null for the same than coverage.

coverage - The source coverage.

Method Detail

getName

public InternationalString getName()

Returns the coverage name, or null if none. The default implementation returns the name specified at construction time.

Returns:

The coverage name, or null.

getDimension

public final int getDimension()

Returns the dimension of this coverage. This is a shortcut for crs.getCoordinateSystem().getDimension().

Returns:

The dimension of this coverage.

getCoordinateReferenceSystem

public 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.

Specified by:

getCoordinateReferenceSystem in interface Coverage

Returns:

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

See Also:

GeneralGridGeometry.getGridToCRS()

getEnvelope

public Envelope getEnvelope()

Returns the bounding box for the coverage domain in coordinate reference system coordinates. May be null if this coverage has no associated coordinate reference system. 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
 

The default implementation returns the domain of validity of the CRS, if there is one.

Specified by:

getEnvelope in interface Coverage

Returns:

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

getRangeType

public 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.

This method is not yet implemented.

Specified by:

getRangeType in interface Coverage

Returns:

The coverage range.

Since:

2.3

evaluate

public Set<Record> evaluate(DirectPosition p,
                            Collection<String> list)

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.

This method is not yet implemented.

Specified by:

evaluate in interface Coverage

Parameters:

p - The position where to evaluate.

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

Returns:

The feature attributes.

Since:

2.3

evaluate

public boolean[] evaluate(DirectPosition coord,
                          boolean[] dest)
                   throws PointOutsideCoverageException,
                          CannotEvaluateException

Returns 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, but it can be changed by some subclasses. The CRS of the point is the same as the grid coverage coordinate reference system.

Specified by:

evaluate in interface Coverage

Parameters:

coord - The coordinate point where to evaluate.

dest - An array in which to store values, or null to create a new array.

Returns:

The dest array, or a newly created array if dest was null.

Throws:

PointOutsideCoverageException - if the evaluation failed because the input point has invalid coordinates.

CannotEvaluateException - if the values can't be computed at the specified coordinate for an other reason. It may be thrown if the coverage data type can't be converted to boolean by an identity or widening conversion. Subclasses may relax this constraint if appropriate.

evaluate

public byte[] evaluate(DirectPosition coord,
                       byte[] dest)
                throws PointOutsideCoverageException,
                       CannotEvaluateException

Returns a sequence of 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, but it can be changed by some subclasses. The CRS of the point is the same as the grid coverage coordinate reference system.

Specified by:

evaluate in interface Coverage

Parameters:

coord - The coordinate point where to evaluate.

dest - An array in which to store values, or null to create a new array.

Returns:

The dest array, or a newly created array if dest was null.

Throws:

PointOutsideCoverageException - if the evaluation failed because the input point has invalid coordinates.

CannotEvaluateException - if the values can't be computed at the specified coordinate for an other reason. It may be thrown if the coverage data type can't be converted to byte by an identity or widening conversion. Subclasses may relax this constraint if appropriate.

evaluate

public int[] evaluate(DirectPosition coord,
                      int[] dest)
               throws PointOutsideCoverageException,
                      CannotEvaluateException

Returns 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, but it can be changed by some subclasses. The CRS of the point is the same as the grid coverage coordinate reference system.

Specified by:

evaluate in interface Coverage

Parameters:

coord - The coordinate point where to evaluate.

dest - An array in which to store values, or null to create a new array.

Returns:

The dest array, or a newly created array if dest was null.

Throws:

PointOutsideCoverageException - if the evaluation failed because the input point has invalid coordinates.

CannotEvaluateException - if the values can't be computed at the specified coordinate for an other reason. It may be thrown if the coverage data type can't be converted to int by an identity or widening conversion. Subclasses may relax this constraint if appropriate.

See Also:

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

evaluate

public float[] evaluate(DirectPosition coord,
                        float[] dest)
                 throws PointOutsideCoverageException,
                        CannotEvaluateException

Returns 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, but it can be changed by some subclasses. The CRS of the point is the same as the grid coverage coordinate reference system.

Specified by:

evaluate in interface Coverage

Parameters:

coord - The coordinate point where to evaluate.

dest - An array in which to store values, or null to create a new array.

Returns:

The dest array, or a newly created array if dest was null.

Throws:

PointOutsideCoverageException - if the evaluation failed because the input point has invalid coordinates.

CannotEvaluateException - if the values can't be computed at the specified coordinate for an other reason. It may be thrown if the coverage data type can't be converted to float by an identity or widening conversion. Subclasses may relax this constraint if appropriate.

See Also:

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

evaluate

public double[] evaluate(DirectPosition coord,
                         double[] dest)
                  throws PointOutsideCoverageException,
                         CannotEvaluateException

Returns 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, but it can be changed by some subclasses. The CRS of the point is the same as the grid coverage coordinate reference system.

Specified by:

evaluate in interface Coverage

Parameters:

coord - The coordinate point where to evaluate.

dest - An array in which to store values, or null to create a new array.

Returns:

The dest array, or a newly created array if dest was null.

Throws:

PointOutsideCoverageException - if the evaluation failed because the input point has invalid coordinates.

CannotEvaluateException - if the values can't be computed at the specified coordinate for an other reason. It may be thrown if the coverage data type can't be converted to double by an identity or widening conversion. Subclasses may relax this constraint if appropriate.

See Also:

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

getRenderableImage

public RenderableImage getRenderableImage(int xAxis,
                                          int yAxis)

Returns 2D view of this grid coverage as a renderable image. This method allows interoperability with Java2D.

Specified by:

getRenderableImage in interface Coverage

Parameters:

xAxis - Dimension to use for the x display axis.

yAxis - Dimension to use for the y display axis.

Returns:

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

show

public void show(String title,
                 int xAxis,
                 int yAxis)

Display this coverage in a windows. This convenience method is used for debugging purpose. The exact appareance of the windows and the tools provided may changes in future versions.

Parameters:

title - The window title, or null for default value.

xAxis - Dimension to use for the x display axis.

yAxis - Dimension to use for the y display axis.

Since:

2.3

show

public void show(String title)

Display this coverage in a windows. This convenience method is used for debugging purpose. The exact appareance of the windows and the tools provided may changes in future versions.

Parameters:

title - The window title, or null for default value.

Since:

2.3

show

public void show()

Displays this coverage in a windows. This convenience method is used for debugging purpose. The exact appareance of the windows and the tools provided may changes in future versions.

getSources

public List<? extends Coverage> getSources()

Returns the source data for a coverage. The default implementation returns an empty list.

Specified by:

getSources in interface Coverage

Returns:

The list of sources data for a coverage.

getLocale

public Locale getLocale()

Returns the default locale for logging, error messages, etc..

Returns:

The default locale for logging and error message.

toString

public String toString()

Returns a string representation of this coverage. This string is for debugging purpose only and may change in future version.

Overrides:

toString in class Object

dispose

public boolean dispose(boolean force)

Provides a hint that a coverage will no longer be accessed from a reference in user space. This can be used as a hint in situations where waiting for garbage collection would be overly conservative. The results of referencing a coverage after a call to dispose are undefined, except if this method returned false.

This method can work in a conservative mode or a forced mode, determined by the force argument:

• If force is false (the recommanded value), this method may process only under some conditions. For example a grid coverage may dispose its planar image only if it has no sinks. This method returns true if it disposed all resources, or false if this method vetoed against the disposal. In the later case, this coverage can still be used.

• If force is true, then this method processes inconditionnally and returns always true. This is a more risky behavior.

The conservative mode (force = false) performs its safety checks on a best-effort basis, with no guarantees. Therefore, it would be wrong to write a program that depended on the safety checks for its correctness. In case of doubt about whatever this coverage still in use or not, it is safer to rely on the garbage collector.

Parameters:

force - true for forcing an inconditionnal disposal, or false for performing a conservative disposal. The recommanded value is false.

Returns:

true if this method disposed at least some resources, or false if this method vetoed against the disposal.

Since:

2.4

See Also:

PlanarImage.dispose()