Package org.geotools.renderer.crs

Class ProjectionHandler

Object

ProjectionHandler

Direct Known Subclasses:

WrappingProjectionHandler

public class ProjectionHandler
extends Object

A class that can perform transformations on geometries to handle the singularity of the rendering CRS, deal with geometries that are crossing the dateline, and eventually wrap them around to produce a seamless continuous map effect.

This basic implementation will cut the geometries that get outside of the area of validity of the projection (as provided by the constructor)

WARNING: this API is not finalized and is meant to be used by StreamingRenderer only

Author:

Andrea Aime - OpenGeo

Field Summary

Fields

Modifier and Type	Field	Description
static final String	ADVANCED_PROJECTION_DENSIFY
protected double	datelineX
static final int	DEFAULT_DENSIFICATION_LIMIT	The default densification limit.
static final String	DENSIFICATION_LIMIT_KEY	System variable that can be used to override the default densification limit.
protected double	densify
protected static final double	EPS
protected SingleCRS	geometryCRS
protected static final Logger	LOGGER
protected boolean	noReprojection
protected boolean	queryAcrossDateline
protected ReferencedEnvelope	renderingEnvelope
protected CRS.AxisOrder	sourceAxisOrder
protected final CoordinateReferenceSystem	sourceCRS
protected CRS.AxisOrder	targetAxisOrder
protected final CoordinateReferenceSystem	targetCRS
protected double	targetHalfCircle
protected final PreparedGeometry	validaAreaTester
protected final Geometry	validArea
protected final ReferencedEnvelope	validAreaBounds

Constructor Summary

Constructors

Constructor	Description
ProjectionHandler(CoordinateReferenceSystem sourceCRS, Envelope validAreaBounds, ReferencedEnvelope renderingEnvelope)	Initializes a projection handler
ProjectionHandler(CoordinateReferenceSystem sourceCRS, Geometry validArea, ReferencedEnvelope renderingEnvelope)	Initializes a projection handler
ProjectionHandler(CoordinateReferenceSystem sourceCRS, Geometry validArea, ReferencedEnvelope renderingEnvelope, boolean keepGeometry)	Initializes a projection handler

Method Summary

Modifier and Type	Method	Description
protected void	accumulateTransforms(MathTransform mt, List<MathTransform> elements)
protected void	addGeometries(List<Geometry> geoms, GeometryCollection collection, String geometryType)	Private method for adding to the input List only the Geometry objects of the input GeometryCollection which belongs to the defined geometryType
protected void	computeDatelineX()
protected MathTransform	concatenateTransforms(List<MathTransform> datumShiftChain)
protected Geometry	densify(Geometry geometry, boolean validate)	Densifies the given geometry using the current densification configuration.
ReferencedEnvelope	getProjectedEnvelope(ReferencedEnvelope envelope, CoordinateReferenceSystem targetCRS)	Reprojects the given envelope to the target CRS, taking into account the ProjectionHandler constraints (valid area bounds, etc.).
List<ReferencedEnvelope>	getQueryEnvelopes()	Returns a set of envelopes that will be used to query the data given the specified rendering envelope and the current query envelope
ReferencedEnvelope	getRenderingEnvelope()	Returns the current rendering envelope
MathTransform	getRenderingTransform(MathTransform mt)	Can modify/wrap the transform to handle specific projection issues
CoordinateReferenceSystem	getSourceCRS()
protected List<ReferencedEnvelope>	getSourceEnvelopes(ReferencedEnvelope renderingEnvelope)
Geometry	getValidArea()	Returns the valid area as a JTS geometry, if it's a complex area (otherwise use getValidAreaBounds())
ReferencedEnvelope	getValidAreaBounds()	Returns the area where the transformation from source to target is valid, expressed in the source coordinate reference system, or null if there is no limit
protected Geometry	intersect(Geometry geometry, Geometry mask, CoordinateReferenceSystem geometryCRS)
protected void	mergeEnvelopes(List<ReferencedEnvelope> envelopes)
Geometry	postProcess(MathTransform mt, Geometry geometry)	Processes the geometry already projected to the target SRS.
Geometry	preProcess(Geometry geometry)	Pre processes the geometry, e.g. cuts it, splits it, etc. in its native srs.
protected void	reprojectEnvelopes(CoordinateReferenceSystem queryCRS, List<ReferencedEnvelope> envelopes)
boolean	requiresProcessing(Geometry geometry)	Returns true if the geometry needs special handling
protected void	setCentralMeridian(double centralMeridian)
void	setProjectionParameters(Map<String,Object> projectionParameters)	Set one of the supported projection parameters: - advancedProjectionDensify (double) if > 0 enables densification on preprocessing with the given distance between points.
protected ReferencedEnvelope	transformEnvelope(ReferencedEnvelope envelope, CoordinateReferenceSystem targetCRS)

Methods inherited from class Object

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

Field Details

ADVANCED_PROJECTION_DENSIFY

public static final String ADVANCED_PROJECTION_DENSIFY

See Also:

• Constant Field Values

EPS

protected static final double EPS

See Also:

• Constant Field Values

LOGGER

protected static final Logger LOGGER

DEFAULT_DENSIFICATION_LIMIT

public static final int DEFAULT_DENSIFICATION_LIMIT

The default densification limit. A Coordinate object is 40 bytes, this number allows the allocation of at most 10MB worth of Coordinate objects

See Also:

• Constant Field Values

DENSIFICATION_LIMIT_KEY

public static final String DENSIFICATION_LIMIT_KEY

System variable that can be used to override the default densification limit.

See Also:

• Constant Field Values

sourceAxisOrder

protected CRS.AxisOrder sourceAxisOrder

targetAxisOrder

protected CRS.AxisOrder targetAxisOrder

renderingEnvelope

protected ReferencedEnvelope renderingEnvelope

validAreaBounds

protected final ReferencedEnvelope validAreaBounds

validArea

protected final Geometry validArea

validaAreaTester

protected final PreparedGeometry validaAreaTester

sourceCRS

protected final CoordinateReferenceSystem sourceCRS

targetCRS

protected final CoordinateReferenceSystem targetCRS

datelineX

protected double datelineX

targetHalfCircle

protected double targetHalfCircle

queryAcrossDateline

protected boolean queryAcrossDateline

geometryCRS

protected SingleCRS geometryCRS

noReprojection

protected boolean noReprojection

densify

protected double densify

Constructor Details

ProjectionHandler

public ProjectionHandler(CoordinateReferenceSystem sourceCRS,
 Envelope validAreaBounds,
 ReferencedEnvelope renderingEnvelope)
                  throws FactoryException

Initializes a projection handler

Parameters:

sourceCRS - The source CRS

validAreaBounds - The valid area (used to cut geometries that go beyond it)

renderingEnvelope - The target rendering area and target CRS

Throws:

FactoryException

ProjectionHandler

public ProjectionHandler(CoordinateReferenceSystem sourceCRS,
 Geometry validArea,
 ReferencedEnvelope renderingEnvelope)
                  throws FactoryException

Initializes a projection handler

Parameters:

sourceCRS - The source CRS

validArea - The valid area (used to cut geometries that go beyond it)

renderingEnvelope - The target rendering area and target CRS

Throws:

FactoryException

ProjectionHandler

public ProjectionHandler(CoordinateReferenceSystem sourceCRS,
 Geometry validArea,
 ReferencedEnvelope renderingEnvelope,
 boolean keepGeometry)
                  throws FactoryException

Initializes a projection handler

Parameters:

sourceCRS - The source CRS

validArea - The valid area (used to cut geometries that go beyond it)

renderingEnvelope - The target rendering area and target CRS

keepGeometry - Can be used to force the valid area to be treated as a polygon, even when it's a rectangle

Throws:

FactoryException

Method Details

setProjectionParameters

public void setProjectionParameters(Map<String,Object> projectionParameters)

Set one of the supported projection parameters: - advancedProjectionDensify (double) if > 0 enables densification on preprocessing with the given distance between points.

getRenderingEnvelope

public ReferencedEnvelope getRenderingEnvelope()

Returns the current rendering envelope

getSourceCRS

public CoordinateReferenceSystem getSourceCRS()

getQueryEnvelopes

public List<ReferencedEnvelope> getQueryEnvelopes()
                                           throws TransformException,
FactoryException

Returns a set of envelopes that will be used to query the data given the specified rendering envelope and the current query envelope

Throws:

TransformException

FactoryException

getSourceEnvelopes

protected List<ReferencedEnvelope> getSourceEnvelopes(ReferencedEnvelope renderingEnvelope)
                                               throws TransformException,
FactoryException

Throws:

TransformException

FactoryException

getProjectedEnvelope

public ReferencedEnvelope getProjectedEnvelope(ReferencedEnvelope envelope,
 CoordinateReferenceSystem targetCRS)
                                        throws TransformException,
FactoryException

Reprojects the given envelope to the target CRS, taking into account the ProjectionHandler constraints (valid area bounds, etc.).

Parameters:

envelope - envelope to reproject

targetCRS - target CRS

Returns:

reprojected envelope

Throws:

TransformException

FactoryException

transformEnvelope

protected ReferencedEnvelope transformEnvelope(ReferencedEnvelope envelope,
 CoordinateReferenceSystem targetCRS)
                                        throws TransformException,
FactoryException

Throws:

TransformException

FactoryException

reprojectEnvelopes

protected void reprojectEnvelopes(CoordinateReferenceSystem queryCRS,
 List<ReferencedEnvelope> envelopes)
                           throws TransformException,
FactoryException

Throws:

TransformException

FactoryException

mergeEnvelopes

protected void mergeEnvelopes(List<ReferencedEnvelope> envelopes)

requiresProcessing

public boolean requiresProcessing(Geometry geometry)

Returns true if the geometry needs special handling

preProcess

public Geometry preProcess(Geometry geometry)
                    throws TransformException,
FactoryException

Pre processes the geometry, e.g. cuts it, splits it, etc. in its native srs. May return null if the geometry is not to be drawn

Throws:

TransformException

FactoryException

densify

protected Geometry densify(Geometry geometry,
 boolean validate)

Densifies the given geometry using the current densification configuration.

It returns the original geometry if densification is not enabled.

intersect

protected Geometry intersect(Geometry geometry,
 Geometry mask,
 CoordinateReferenceSystem geometryCRS)

getRenderingTransform

public MathTransform getRenderingTransform(MathTransform mt)
                                    throws FactoryException

Can modify/wrap the transform to handle specific projection issues

Throws:

FactoryException

concatenateTransforms

protected MathTransform concatenateTransforms(List<MathTransform> datumShiftChain)

accumulateTransforms

protected void accumulateTransforms(MathTransform mt,
 List<MathTransform> elements)

postProcess

public Geometry postProcess(MathTransform mt,
 Geometry geometry)

Processes the geometry already projected to the target SRS. May return null if the geometry is not to be drawn.

Parameters:

mt - optional reverse transformation to facilitate unwrapping

getValidAreaBounds

public ReferencedEnvelope getValidAreaBounds()

Returns the area where the transformation from source to target is valid, expressed in the source coordinate reference system, or null if there is no limit

getValidArea

public Geometry getValidArea()

Returns the valid area as a JTS geometry, if it's a complex area (otherwise use getValidAreaBounds())

Returns:

setCentralMeridian

protected void setCentralMeridian(double centralMeridian)

computeDatelineX

protected void computeDatelineX()

addGeometries

protected void addGeometries(List<Geometry> geoms,
 GeometryCollection collection,
 String geometryType)

Private method for adding to the input List only the Geometry objects of the input GeometryCollection which belongs to the defined geometryType